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Restructuring and Related Activities [Abstract]

DISCONTINUED OPERATIONS

The results of our former Performance Materials Division (PMD) and Energy-from-Waste (EfW) segment are reflected in our consolidated financial statements as discontinued operations.

During the second quarter of fiscal year 2017, we completed the sale of PMD to Evonik Industries AG (Evonik) for $3.8 billion in cash. A gain of $2,870 ($1,833 after-tax, or $8.34 per share) was recognized on the sale, which closed on 3 January 2017.

In fiscal year 2016, we discontinued efforts to start up and operate two EfW projects located in Tees Valley, United Kingdom. During the first quarter of fiscal year 2017, we recorded a loss on disposal of $59.3 ($47.1 after-tax), primarily for land lease obligations and to update our estimate of the net realizable value of the plant assets. The loss on disposal was recorded as a component of discontinued operations while the liability associated with land lease obligations was and continues to be recorded in continuing operations. The liability recorded in continuing operations was approximately $68 as of 31 March 2018.

Summarized Financial Information of Discontinued Operations

For the three and six months ended 31 March 2018, the loss from discontinued operations, net of tax, on the consolidated income statements was $0.0 and $1.0, respectively. The year-to-date loss is related to EfW project exit activities and administrative costs.

The following table details the businesses and major line items that comprise income from discontinued operations, net of tax, on the consolidated income statements for the three and six months ended 31 March 2017:



	Three Months Ended
	31 March 2017
							Total
	Performance			Energy-			Discontinued
	Materials			from-Waste^(A)			Operations
Cost of sales		$3.3			$3.0			$6.3
Selling and administrative	2.1			—			2.1
Other income (expense), net	.7			(.4		)	.3
Income (Loss) Before Taxes	(4.7		)	(3.4		)	(8.1		)
Income tax benefit	(.3		)	(.9		)	(1.2		)
Income (Loss) From Operations of Discontinued Operations, net of tax	(4.4		)	(2.5		)	(6.9		)
Gain on Disposal, net of tax	1,832.5			—			1,832.5
Income (Loss) From Discontinued Operations, net of tax		$1,828.1			($2.5	)		$1,825.6




	Six Months Ended
	31 March 2017
							Total
	Performance			Energy-			Discontinued
	Materials			from-Waste^(A)			Operations
Sales		$254.8			$—			$254.8
Cost of sales	182.3			9.6			191.9
Selling and administrative	22.5			.2			22.7
Research and development	5.1			—			5.1
Other income (expense), net	.3			(.1		)	.2
Operating Income (Loss)	45.2			(9.9		)	35.3
Equity affiliates’ income	.3			—			.3
Income (Loss) Before Taxes	45.5			(9.9		)	35.6
Income tax benefit^(B)	(50.8		)	(2.0		)	(52.8		)
Income (Loss) From Operations of Discontinued Operations, net of tax	96.3			(7.9		)	88.4
Gain (Loss) on Disposal, net of tax	1,832.5			(47.1		)	1,785.4
Income (Loss) From Discontinued Operations, net of tax		$1,928.8			($55.0	)		$1,873.8


^(A)	The loss from operations of discontinued operations for EfW primarily relates to land lease obligations, administrative costs, and costs incurred for project exit activities.


^(B)	As a result of the expected gain on the sale of PMD, we released valuation allowances related to capital loss and net operating loss carryforwards during the first quarter of 2017 that favorably impacted our income tax provision within discontinued operations by approximately $66.

There were no assets or liabilities presented in discontinued operations on the consolidated balance sheets as of 31 March 2018. Current assets of discontinued operations on the consolidated balance sheets of $10.2 as of 30 September 2017 related to EfW. Current liabilities of discontinued operations on the consolidated balance sheets of $15.7 as of 30 September 2017 primarily related to reserves associated with the disposition of PMD.

Materials Technologies Separation	6 Months Ended
Materials Technologies Separation	Mar. 31, 2018
Restructuring and Related Activities [Abstract]
Materials Technologies Separation	MATERIALS TECHNOLOGIES SEPARATION In fiscal year 2017, we completed the separation of the divisions comprising the former Materials Technologies segment. As further discussed below, we completed the separation of the Electronic Materials Division (EMD) through the spin-off of Versum Materials, Inc. (Versum). For information on the disposition of PMD, refer to Note 3, Discontinued Operations. Spin-off of EMD On 1 October 2016 (the distribution date), Air Products completed the spin-off of Versum into a separate and independent public company. The spin-off was completed by way of a distribution to Air Products’ stockholders of all of the then issued and outstanding shares of common stock of Versum on the basis of one share of Versum common stock for every two shares of Air Products’ common stock held as of the close of business on 21 September 2016 (the record date for the distribution). Fractional shares of Versum common stock were not distributed to Air Products' common stockholders. Air Products’ stockholders received cash in lieu of fractional shares. The spin-off of Versum was treated as a noncash transaction in the consolidated statements of cash flows in fiscal year 2017. There has been no activity in discontinued operations on the consolidated income statements and no assets or liabilities presented in discontinued operations on the consolidated balance sheets related to EMD for the periods presented. Business Separation Costs In connection with the dispositions of EMD and PMD, we incurred net separation costs of $30.2 for the six months ended 31 March 2017. No business separation costs were incurred during the second quarter of fiscal year 2017. The net costs include legal and advisory fees of $32.5, which are reflected on the consolidated income statements as “Business separation costs,” and a pension settlement benefit of $2.3 that is now presented within "Other non-operating income (expense), net" as a result of the adoption of pension guidance at the beginning of fiscal year 2018. Refer to Note 2, New Accounting Guidance, for additional information. No business separation costs were incurred during fiscal year 2018.

Cost Reduction and Asset Actions

6 Months Ended

Mar. 31, 2018

Cost Reduction and Asset Actions

COST REDUCTION AND ASSET ACTIONS

For the three months ended 31 March 2017, we recognized an expense of $10.3 for severance and other benefits related to cost reduction actions. For the six months ended 31 March 2017, we recognized a net expense of $60.3, which included $45.7 for asset actions and $18.0 for severance and other benefits. These expenses were partially offset by the favorable settlement of the remaining accrual from prior year actions discussed below.

In fiscal year 2017, we recognized a net expense of $151.4. The net expense included a charge of $154.8 for actions taken during fiscal year 2017, including asset actions of $88.5 and severance and other benefits of $66.3, partially offset by the favorable settlement of the remaining $3.4 accrued balance associated with business restructuring actions taken in 2015. The 2017 charge related to the segments as follows: $39.3 in Industrial Gases – Americas, $77.9 in Industrial Gases – EMEA, $.9 in Industrial Gases – Asia, $2.5 in Industrial Gases – Global, and $34.2 in Corporate and other. The charges we record for cost reduction and asset actions have been excluded from segment operating income.

The following table summarizes the carrying amount of the accrual for cost reduction and asset actions at 31 March 2018:



	Severance and Other Benefits			Asset Actions/Other			Total
30 September 2016		$12.3			$—			$12.3
2017 Charge	66.3			88.5			154.8
Noncash expenses	—			(84.2		)	(84.2		)
Amount reflected in pension liability	(2.0		)	—			(2.0		)
Amount reflected in other noncurrent liabilities	—			(2.2		)	(2.2		)
Cash expenditures	(35.7		)	(1.2		)	(36.9		)
Currency translation adjustment	(.3		)	—			(.3		)
30 September 2017		$40.6			$.9			$41.5
Amount reflected in pension liability	(.4		)	—			(.4		)
Cash expenditures	(23.9		)	(.2		)	(24.1		)
Currency translation adjustment	.7			—			.7
31 March 2018		$17.0			$.7			$17.7

Business Combinations	6 Months Ended
Business Combinations	Mar. 31, 2018
Business Combinations [Abstract]
Business Combinations	BUSINESS COMBINATIONS During the first half of fiscal year 2018, we completed five acquisitions with an aggregate purchase price, net of cash acquired, of $281.0. The largest acquisition was completed during the first quarter of fiscal year 2018 and consists primarily of three air separation units serving onsite and merchant customers in China. This acquisition is expected to strengthen our position in the region. The results of this business are consolidated within our Industrial Gases – Asia segment. The 2018 acquisitions resulted in the recognition of $168.9 of plant and equipment, $62.9 of goodwill, $3.0 of which is deductible for tax purposes, and $65.3 of intangible assets, primarily customer relationships, having a weighted-average useful life of twelve years. The goodwill recognized on the transactions is attributable to expected growth and cost synergies and was recorded in the Industrial Gases – Asia and the Industrial Gases – EMEA segments. These acquisitions did not materially impact our consolidated income statements for the periods presented. Subsequent Event On 10 September 2017, Air Products signed an agreement to form a joint venture, Air Products Lu’an (Changzhi) Co., Ltd. (“the JV”) with Lu’An Clean Energy Company ("Lu’An"). The JV will receive coal, steam and power from Lu’An and will supply syngas to Lu’An under a long-term onsite contract. On 26 April 2018, we completed the formation of the JV, which Air Products will consolidate and of which Air Products owns 60% and Lu’An owns 40%. Air Products contributed four large air separation units to the JV having a carrying value of approximately $300. In addition, on 26 April 2018 (“the acquisition date”), the JV acquired gasification and syngas clean-up assets from Lu’An (“the acquisition”). In connection with the closing of the acquisition, we paid cash of approximately 1.7 billion RMB (approximately $270) and expect to make a final payment of approximately 1.5 billion RMB (approximately $230 as of 26 April 2018) in the fourth quarter of 2018. The transaction will be accounted for as a business combination. The JV will be consolidated within the results of the Industrial Gases – Asia segment following the acquisition date. The initial accounting for the business combination is incomplete as of the date of this report. In total, we expect the carrying value of the plant and equipment of the joint venture to be approximately $1.3 billion, subject to the completion of an asset valuation.

Inventories

6 Months Ended

Mar. 31, 2018

Inventory Disclosure [Abstract]

Inventories

INVENTORIES

The components of inventories are as follows:



	31 March			30 September
	2018			2017
Finished goods		$134.3			$120.0
Work in process	16.1			15.7
Raw materials, supplies and other	213.6			223.0
Total FIFO cost		$364.0			$358.7
Less: Excess of FIFO cost over LIFO cost	(24.1		)	(23.3		)
Inventories		$339.9			$335.4

First-in, first-out (FIFO) cost approximates replacement cost.

Goodwill

6 Months Ended

Mar. 31, 2018

Goodwill and Intangible Assets Disclosure [Abstract]

Goodwill

GOODWILL

Changes to the carrying amount of consolidated goodwill by segment for the six months ended 31 March 2018 are as follows:



	Industrial Gases– Americas		Industrial Gases– EMEA		Industrial Gases– Asia		Industrial Gases– Global		Total
Goodwill, net at 30 September 2017		$163.7		$402.4		$135.2		$20.2		$721.5
Acquisitions	—		27.7		35.2		—		62.9
Currency translation	3.5		22.0		5.0		.1		30.6
Goodwill, net at 31 March 2018		$167.2		$452.1		$175.4		$20.3		$815.0



	31 March			30 September
	2018			2017
Goodwill, gross		$1,257.0			$1,138.7
Accumulated impairment losses	(442.0		)	(417.2		)
Goodwill, net		$815.0			$721.5

We review goodwill for impairment annually in the fourth quarter of the fiscal year and whenever events or changes in circumstances indicate that the carrying value of goodwill might not be recoverable.

The accumulated impairment losses of $442.0 as of 31 March 2018 are attributable to LASA within the Industrial Gases –Americas segment and include impairment charges recorded in previous years as well as the impacts of currency translation on the losses.

Financial Instruments

6 Months Ended

Mar. 31, 2018

Derivative Instruments and Hedging Activities Disclosure [Abstract]

Financial Instruments

FINANCIAL INSTRUMENTS

Currency Price Risk Management

Our earnings, cash flows, and financial position are exposed to foreign currency risk from foreign currency-denominated transactions and net investments in foreign operations. It is our policy to seek to minimize our cash flow volatility from changes in currency exchange rates. This is accomplished by identifying and evaluating the risk that our cash flows will change in value due to changes in exchange rates and by executing the appropriate strategies necessary to manage such exposures. Our objective is to maintain economically balanced currency risk management strategies that provide adequate downside protection.

Forward Exchange Contracts

We enter into forward exchange contracts to reduce the cash flow exposure to foreign currency fluctuations associated with highly anticipated cash flows and certain firm commitments, such as the purchase of plant and equipment. We also enter into forward exchange contracts to hedge the cash flow exposure on intercompany loans. This portfolio of forward exchange contracts consists primarily of Euros and U.S. Dollars. The maximum remaining term of any forward exchange contract currently outstanding and designated as a cash flow hedge at 31 March 2018 is 2.0 years.

Forward exchange contracts are also used to hedge the value of investments in certain foreign subsidiaries and affiliates by creating a liability in a currency in which we have a net equity position. The primary currency pair in this portfolio of forward exchange contracts is Euros and U.S. Dollars.

In addition to the forward exchange contracts that are designated as hedges, we utilize forward exchange contracts that are not designated as hedges. The primary objective of these forward exchange contracts is to protect the value of foreign currency-denominated monetary assets and liabilities, primarily working capital, from the effects of volatility in foreign exchange rates that might occur prior to their receipt or settlement. This portfolio of forward exchange contracts comprises many different foreign currency pairs, with a profile that changes from time to time depending on business activity and sourcing decisions.

The table below summarizes our outstanding currency price risk management instruments:



	31 March 2018			30 September 2017
	US$ Notional		Years Average Maturity	US$ Notional		Years Average Maturity
Forward Exchange Contracts:
Cash flow hedges		$2,953.8	.4		$3,150.2	.4
Net investment hedges	369.5		2.5	675.5		3.0
Not designated	990.0		1.7	273.8		.1
Total Forward Exchange Contracts		$4,313.3	.9		$4,099.5	.8

The notional value of forward exchange contracts not designated increased from the prior year. As a result of changes in our currency exposures, we de-designated a portion of forward exchange contracts previously designated as net investment hedges. To eliminate any future earnings impact of the de-designated portion, we entered into equal and offsetting forward exchange contracts.

In addition to the above, we use foreign currency-denominated debt to hedge the foreign currency exposures of our net investment in certain foreign subsidiaries. The designated foreign currency-denominated debt and related accrued interest included €914.6 million ($1,127.1) at 31 March 2018 and €912.2 million ($1,077.7) at 30 September 2017. The designated foreign currency-denominated debt is located on the balance sheet in the long-term debt line item.

Debt Portfolio Management

It is our policy to identify on a continuing basis the need for debt capital and evaluate the financial risks inherent in funding the Company with debt capital. Reflecting the result of this ongoing review, the debt portfolio and hedging program are managed with the objectives and intent to (1) reduce funding risk with respect to borrowings made by us to preserve our access to debt capital and provide debt capital as required for funding and liquidity purposes, and (2) manage the aggregate interest rate risk and the debt portfolio in accordance with certain debt management parameters.

Interest Rate Management Contracts

We enter into interest rate swaps to change the fixed/variable interest rate mix of our debt portfolio in order to maintain the percentage of fixed- and variable-rate debt within the parameters set by management. In accordance with these parameters, the agreements are used to manage interest rate risks and costs inherent in our debt portfolio. Our interest rate management portfolio generally consists of fixed-to-floating interest rate swaps (which are designated as fair value hedges), pre-issuance interest rate swaps and treasury locks (which hedge the interest rate risk associated with anticipated fixed-rate debt issuances and are designated as cash flow hedges), and floating-to-fixed interest rate swaps (which are designated as cash flow hedges). At 31 March 2018, the outstanding interest rate swaps were denominated in U.S. Dollars. The notional amount of the interest rate swap agreements is equal to or less than the designated debt being hedged. When interest rate swaps are used to hedge variable-rate debt, the indices of the swaps and the debt to which they are designated are the same. It is our policy not to enter into any interest rate management contracts which lever a move in interest rates on a greater than one-to-one basis.

Cross Currency Interest Rate Swap Contracts

We enter into cross currency interest rate swap contracts when our risk management function deems necessary. These contracts may entail both the exchange of fixed- and floating-rate interest payments periodically over the life of the agreement and the exchange of one currency for another currency at inception and at a specified future date. The contracts are used to hedge either certain net investments in foreign operations or non-functional currency cash flows related to intercompany loans. The current cross currency interest rate swap portfolio consists of fixed-to-fixed swaps primarily between U.S. Dollars and offshore Chinese Renminbi, U.S. Dollars and Chilean Pesos, and U.S. Dollars and British Pound Sterling.

The following table summarizes our outstanding interest rate management contracts and cross currency interest rate swaps:



	31 March 2018							30 September 2017
	US$ Notional		Average Pay %		Average Receive %		Years Average Maturity	US$ Notional		Average Pay %		Average Receive %		Years Average Maturity
Interest rate swaps (fair value hedge)		$400.0	LIBOR		2.53	%	1.4		$600.0	LIBOR		2.28	%	1.3
Cross currency interest rate swaps (net investment hedge)		$688.7	3.73	%	2.76	%	2.3		$539.7	3.27	%	2.59	%	1.9
Cross currency interest rate swaps (cash flow hedge)		$1,014.6	5.01	%	2.75	%	2.4		$1,095.7	4.96	%	2.78	%	2.4
Cross currency interest rate swaps (not designated)		$39.5	3.16	%	2.88	%	1.5		$41.6	3.28	%	2.32	%	1.7

The table below summarizes the fair value and balance sheet location of our outstanding derivatives:



	Balance Sheet Location	31 March 2018		30 September 2017		Balance Sheet Location	31 March 2018		30 September 2017
Derivatives Designated as Hedging Instruments:
Forward exchange contracts	Other receivables		$81.7		$81.7	Accrued liabilities		$31.6		$82.0
Interest rate management contracts	Other receivables	5.5		11.1		Accrued liabilities	19.4		10.7
Forward exchange contracts	Other noncurrent assets	9.1		27.1		Other noncurrent liabilities	19.7		13.8
Interest rate management contracts	Other noncurrent assets	43.5		102.6		Other noncurrent liabilities	58.1		22.2
Total Derivatives Designated as Hedging Instruments			$139.8		$222.5			$128.8		$128.7
Derivatives Not Designated as Hedging Instruments:
Forward exchange contracts	Other receivables		$4.4		$1.1	Accrued liabilities		$5.4		$2.2
Interest rate management contracts	Other receivables	—		—		Accrued liabilities	.4		1.0
Forward exchange contracts	Other noncurrent assets	9.5		—		Other noncurrent liabilities	17.0		—
Interest rate management contracts	Other noncurrent assets	3.9		4.2		Other noncurrent liabilities	—		—
Total Derivatives Not Designated as Hedging Instruments			$17.8		$5.3			$22.8		$3.2
Total Derivatives			$157.6		$227.8			$151.6		$131.9

Refer to Note 10, Fair Value Measurements, which defines fair value, describes the method for measuring fair value, and provides additional disclosures regarding fair value measurements.

The table below summarizes the gain or loss related to our cash flow hedges, fair value hedges, net investment hedges, and derivatives not designated as hedging instruments:



	Three Months Ended 31 March
	Forward Exchange Contracts						Foreign Currency Debt						Other ^(A)						Total
	2018			2017			2018			2017			2018			2017			2018			2017
Cash Flow Hedges, net of tax:
Net gain (loss) recognized in OCI (effective portion)		$31.9			$11.1			$—			$—			($14.1	)		($26.5	)		$17.8			($15.4	)
Net (gain) loss reclassified from OCI to sales/cost of sales (effective portion)	4.0			1.2			—			—			—			—			4.0			1.2
Net (gain) loss reclassified from OCI to other income (expense), net (effective portion)	(29.3		)	(10.8		)	—			—			15.8			15.8			(13.5		)	5.0
Net (gain) loss reclassified from OCI to interest expense (effective portion)	1.6			(1.6		)	—			—			.7			.7			2.3			(.9		)
Net (gain) loss reclassified from OCI to other income (expense), net (ineffective portion)	(.3		)	.5			—			—			—			—			(.3		)	.5
Fair Value Hedges:
Net gain (loss) recognized in interest expense^(B)		$—			$—			$—			$—			($3.6	)		($2.8	)		($3.6	)		($2.8	)
Net Investment Hedges, net of tax:
Net gain (loss) recognized in OCI		($15.2	)		($.8	)		($22.2	)		($7.8	)		($23.3	)		($6.5	)		($60.7	)		($15.1	)
Derivatives Not Designated as Hedging Instruments:
Net gain (loss) recognized in other income (expense), net^(C)		$1.6			($2.5	)		$—			$—			($2.2	)		($.6	)		($.6	)		($3.1	)




	Six Months Ended 31 March
	Forward Exchange Contracts						Foreign Currency Debt					Other ^(A)						Total
	2018			2017			2018			2017		2018			2017			2018			2017
Cash Flow Hedges, net of tax:
Net gain (loss) recognized in OCI (effective portion)		$39.4			($48.3	)		$—			$—		($31.1	)		$23.1			$8.3			($25.2	)
Net (gain) loss reclassified from OCI to sales/cost of sales (effective portion)	5.0			5.8			—			—		—			—			5.0			5.8
Net (gain) loss reclassified from OCI to other income (expense), net (effective portion)	(46.9		)	38.7			—			—		32.2			(12.4		)	(14.7		)	26.3
Net (gain) loss reclassified from OCI to interest expense (effective portion)	2.2			(2.4		)	—			—		1.3			1.4			3.5			(1.0		)
Net (gain) loss reclassified from OCI to other income (expense), net (ineffective portion)	(.5		)	.3			—			—		—			—			(.5		)	.3
Fair Value Hedges:
Net gain (loss) recognized in interest expense^(B)		$—			$—			$—			$—		($6.8	)		($11.9	)		($6.8	)		($11.9	)
Net Investment Hedges, net of tax:
Net gain (loss) recognized in OCI		($22.7	)		$27.1			($39.5	)		$34.0		($34.5	)		$6.6			($96.7	)		$67.7
Derivatives Not Designated as Hedging Instruments:
Net gain (loss) recognized in other income (expense), net^(C)		$.1			($.4	)		$—			$—		($3.5	)		$.2			($3.4	)		($.2	)


^(A)	Other includes the impact on other comprehensive income (OCI) and earnings primarily related to interest rate and cross currency interest rate swaps.


^(B)	The impact of fair value hedges noted above was largely offset by recognized gains and losses resulting from the impact of changes in related interest rates on outstanding debt.


^(C)	The impact of the non-designated hedges noted above was largely offset by recognized gains and losses resulting from the impact of changes in exchange rates on assets and liabilities denominated in non-functional currencies.

The amount of cash flow hedges’ unrealized gains and losses at 31 March 2018 that are expected to be reclassified to earnings in the next twelve months is not material.

The cash flows related to all derivative contracts are reported in the operating activities section of the consolidated statements of cash flows.

Credit Risk-Related Contingent Features

Certain derivative instruments are executed under agreements that require us to maintain a minimum credit rating with both Standard & Poor’s and Moody’s. If our credit rating falls below this threshold, the counterparty to the derivative instruments has the right to request full collateralization on the derivatives’ net liability position. The net liability position of derivatives with credit risk-related contingent features was $116.9 as of 31 March 2018 and $34.6 as of 30 September 2017. Because our current credit rating is above the various pre-established thresholds, no collateral has been posted on these liability positions.

Counterparty Credit Risk Management

We execute financial derivative transactions with counterparties that are highly rated financial institutions, all of which are investment grade at this time. Some of our underlying derivative agreements give us the right to require the institution to post collateral if its credit rating falls below the pre-established thresholds with Standard & Poor’s or Moody’s. The collateral that the counterparties would be required to post was $70.9 as of 31 March 2018 and $138.5 as of 30 September 2017. No financial institution is required to post collateral at this time as all have credit ratings at or above threshold.

Fair Value Measurements

6 Months Ended

Mar. 31, 2018

Fair Value Disclosures [Abstract]

Fair Value Measurements

FAIR VALUE MEASUREMENTS

Fair value is defined as an exit price, i.e., the price that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date.

The fair value hierarchy prioritizes the inputs to valuation techniques used to measure fair value into three broad levels as follows:


Level 1	— Quoted prices (unadjusted) in active markets for identical assets or liabilities.


Level 2	— Inputs that are observable for the asset or liability, either directly or indirectly through market corroboration, for substantially the full term of the asset or liability.


Level 3	— Inputs that are unobservable for the asset or liability based on our own assumptions (about the assumptions market participants would use in pricing the asset or liability).

The methods and assumptions used to measure the fair value of financial instruments are as follows:

Short-term Investments

Short-term investments primarily include time deposits and treasury securities with original maturities greater than three months and less than one year. The estimated fair value of the short-term investments, which approximates carrying value as of 31 March 2018 and 30 September 2017, was determined using level 2 inputs within the fair value hierarchy. Level 2 measurements were based on current interest rates for similar investments with comparable credit risk and time to maturity.

Derivatives

The fair value of our interest rate management contracts and forward exchange contracts are quantified using the income approach and are based on estimates using standard pricing models. These models take into account the value of future cash flows as of the balance sheet date, discounted to a present value using discount factors that match both the time to maturity and currency of the underlying instruments. The computation of the fair values of these instruments is generally performed by the Company. These standard pricing models utilize inputs which are derived from or corroborated by observable market data such as interest rate yield curves as well as currency spot and forward rates. Therefore, the fair value of our derivatives is classified as a level 2 measurement. On an ongoing basis, we randomly test a subset of our valuations against valuations received from the transaction’s counterparty to validate the accuracy of our standard pricing models. Counterparties to these derivative contracts are highly rated financial institutions.

Refer to Note 9, Financial Instruments, for a description of derivative instruments, including details on the balance sheet line classifications.

Long-term Debt

The fair value of our debt is based on estimates using standard pricing models that take into account the value of future cash flows as of the balance sheet date, discounted to a present value using discount factors that match both the time to maturity and currency of the underlying instruments. These standard valuation models utilize observable market data such as interest rate yield curves and currency spot rates. Therefore, the fair value of our debt is classified as a level 2 measurement. We generally perform the computation of the fair value of these instruments.

The carrying values and fair values of financial instruments were as follows:



	31 March 2018				30 September 2017
	Carrying Value		Fair Value		Carrying Value		Fair Value
Assets
Derivatives
Forward exchange contracts		$104.7		$104.7		$109.9		$109.9
Interest rate management contracts	52.9		52.9		117.9		117.9
Liabilities
Derivatives
Forward exchange contracts		$73.7		$73.7		$98.0		$98.0
Interest rate management contracts	77.9		77.9		33.9		33.9
Long-term debt, including current portion	3,454.0		3,459.5		3,818.8		3,928.2

The carrying amounts reported in the balance sheet for cash and cash items, short-term investments, trade receivables, payables and accrued liabilities, accrued income taxes, and short-term borrowings approximate fair value due to the short-term nature of these instruments. Accordingly, these items have been excluded from the above table.

The following table summarizes assets and liabilities measured at fair value on a recurring basis in the consolidated balance sheets:



	31 March 2018								30 September 2017
	Total		Level 1		Level 2		Level 3		Total		Level 1		Level 2		Level 3
Assets at Fair Value
Derivatives
Forward exchange contracts		$104.7		$—		$104.7		$—		$109.9		$—		$109.9		$—
Interest rate management contracts	52.9		—		52.9		—		117.9		—		117.9		—
Total Assets at Fair Value		$157.6		$—		$157.6		$—		$227.8		$—		$227.8		$—
Liabilities at Fair Value
Derivatives
Forward exchange contracts		$73.7		$—		$73.7		$—		$98.0		$—		$98.0		$—
Interest rate management contracts	77.9		—		77.9		—		33.9		—		33.9		—
Total Liabilities at Fair Value		$151.6		$—		$151.6		$—		$131.9		$—		$131.9		$—

- Definition

The entire disclosure for the fair value of financial instruments (as defined), including financial assets and financial liabilities (collectively, as defined), and the measurements of those instruments as well as disclosures related to the fair value of non-financial assets and liabilities. Such disclosures about the financial instruments, assets, and liabilities would include: (1) the fair value of the required items together with their carrying amounts (as appropriate); (2) for items for which it is not practicable to estimate fair value, disclosure would include: (a) information pertinent to estimating fair value (including, carrying amount, effective interest rate, and maturity, and (b) the reasons why it is not practicable to estimate fair value; (3) significant concentrations of credit risk including: (a) information about the activity, region, or economic characteristics identifying a concentration, (b) the maximum amount of loss the entity is exposed to based on the gross fair value of the related item, (c) policy for requiring collateral or other security and information as to accessing such collateral or security, and (d) the nature and brief description of such collateral or security; (4) quantitative information about market risks and how such risks are managed; (5) for items measured on both a recurring and nonrecurring basis information regarding the inputs used to develop the fair value measurement; and (6) for items presented in the financial statement for which fair value measurement is elected: (a) information necessary to understand the reasons for the election, (b) discussion of the effect of fair value changes on earnings, (c) a description of [similar groups] items for which the election is made and the relation thereof to the balance sheet, the aggregate carrying value of items included in the balance sheet that are not eligible for the election; (7) all other required (as defined) and desired information.

+ References + Details

Retirement Benefits

6 Months Ended

Mar. 31, 2018

Retirement Benefits [Abstract]

Retirement Benefits

RETIREMENT BENEFITS

The components of net periodic benefit cost for the defined benefit pension plans for the three and six months ended 31 March 2018 and 2017 were as follows:



	Pension Benefits
	2018						2017
Three Months Ended 31 March	U.S.			International			U.S.			International
Service cost		$6.4			$6.6			$6.9			$6.3
Interest cost	26.8			9.6			27.6			7.9
Expected return on plan assets	(50.4		)	(21.1		)	(51.7		)	(18.3		)
Prior service cost amortization	.4			—			.6			(.1		)
Actuarial loss amortization	22.2			10.3			20.9			13.2
Settlements	1.5			—			4.1			4.0
Curtailment	—			—			.1			1.8
Special termination benefits	.4			—			(.1		)	.1
Other	—			.1			—			(2.2		)
Net Periodic Benefit Cost (Total)		$7.3			$5.5			$8.4			$12.7
Less: Discontinued Operations	—			—			(.1		)	(3.4		)
Net Periodic Benefit Cost (Continuing Operations)		$7.3			$5.5			$8.3			$9.3




	Pension Benefits
	2018						2017
Six Months Ended 31 March	U.S.			International			U.S.			International
Service cost^(A)		$12.8			$12.9			$15.2			$13.0
Interest cost	53.5			18.8			52.5			15.5
Expected return on plan assets	(100.8		)	(41.3		)	(104.4		)	(36.8		)
Prior service cost amortization	.8			—			1.2			(.1		)
Actuarial loss amortization	43.9			20.3			47.0			27.1
Settlements	3.3			—			4.1			1.7
Curtailment	—			—			4.3			(1.3		)
Special termination benefits	.4			—			1.0			.5
Other	—			.6			—			.5
Net Periodic Benefit Cost (Total)		$13.9			$11.3			$20.9			$20.1
Less: Discontinued Operations	—			—			(.7		)	(4.1		)
Net Periodic Benefit Cost (Continuing Operations)		$13.9			$11.3			$20.2			$16.0


^(A)	Includes total service costs from discontinued operations of $1.3 for the six months ended 31 March 2017.

As noted in Note 2, New Accounting Guidance, we early adopted guidance on the presentation of net periodic pension and postretirement benefit cost during the first quarter of fiscal year 2018. The amendments require that the service cost component of the net periodic benefit cost be presented in the same line items as other compensation costs arising from services rendered by employees during the period. The non-service related costs are presented outside of operating income in "Other non-operating income (expense), net."

Service costs are primarily included in "Cost of sales" and "Selling and administrative" on our consolidated income statements. The costs capitalized in fiscal year 2018 and 2017 were not material.

For the six months ended 31 March 2018 and 2017, our cash contributions to funded pension plans and benefit payments under unfunded pension plans were $35.9 and $40.8, respectively. Total contributions for fiscal year 2018 are expected to be approximately $50 to $70. During fiscal year 2017, total contributions were $64.1.

Commitments and Contingencies	6 Months Ended
Commitments and Contingencies	Mar. 31, 2018
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	COMMITMENTS AND CONTINGENCIES Litigation We are involved in various legal proceedings, including commercial, competition, environmental, health, safety, product liability, and insurance matters. In September 2010, the Brazilian Administrative Council for Economic Defense (CADE) issued a decision against our Brazilian subsidiary, Air Products Brasil Ltda., and several other Brazilian industrial gas companies for alleged anticompetitive activities. CADE imposed a civil fine of R$179.2 million (approximately $54 at 31 March 2018) on Air Products Brasil Ltda. This fine was based on a recommendation by a unit of the Brazilian Ministry of Justice, whose investigation began in 2003, alleging violation of competition laws with respect to the sale of industrial and medical gases. The fines are based on a percentage of our total revenue in Brazil in 2003. We have denied the allegations made by the authorities and filed an appeal in October 2010 with the Brazilian courts. On 6 May 2014, our appeal was granted and the fine against Air Products Brasil Ltda. was dismissed. CADE has appealed that ruling and the matter remains pending. We, with advice of our outside legal counsel, have assessed the status of this matter and have concluded that, although an adverse final judgment after exhausting all appeals is possible, such a judgment is not probable. As a result, no provision has been made in the consolidated financial statements. We estimate the maximum possible loss to be the full amount of the fine of R$179.2 million (approximately $54 at 31 March 2018) plus interest accrued thereon until final disposition of the proceedings. Other than this matter, we do not currently believe there are any legal proceedings, individually or in the aggregate, that are reasonably possible to have a material impact on our financial condition, results of operations, or cash flows. Environmental In the normal course of business, we are involved in legal proceedings under the Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA: the federal Superfund law); Resource Conservation and Recovery Act (RCRA); and similar state and foreign environmental laws relating to the designation of certain sites for investigation or remediation. Presently, there are 33 sites on which a final settlement has not been reached where we, along with others, have been designated a potentially responsible party by the Environmental Protection Agency or are otherwise engaged in investigation or remediation, including cleanup activity at certain of our current and former manufacturing sites. We continually monitor these sites for which we have environmental exposure. Accruals for environmental loss contingencies are recorded when it is probable that a liability has been incurred and the amount of loss can be reasonably estimated. The consolidated balance sheets at 31 March 2018 and 30 September 2017 included an accrual of $81.0 and $83.6, respectively, primarily as part of other noncurrent liabilities. The environmental liabilities will be paid over a period of up to 30 years. We estimate the exposure for environmental loss contingencies to range from $80 to a reasonably possible upper exposure of $95 as of 31 March 2018. Actual costs to be incurred at identified sites in future periods may vary from the estimates, given inherent uncertainties in evaluating environmental exposures. Using reasonably possible alternative assumptions of the exposure level could result in an increase to the environmental accrual. Due to the inherent uncertainties related to environmental exposures, a significant increase to the reasonably possible upper exposure level could occur if a new site is designated, the scope of remediation is increased, a different remediation alternative is identified, or a significant increase in our proportionate share occurs. We do not expect that any sum we may have to pay in connection with environmental matters in excess of the amounts recorded or disclosed above would have a material adverse impact on our financial position or results of operations in any one year. PACE At 31 March 2018, $28.2 of the environmental accrual was related to the Pace facility. In 2006, we sold our Amines business, which included operations at Pace, Florida, and recognized a liability for retained environmental obligations associated with remediation activities at Pace. We are required by the Florida Department of Environmental Protection (FDEP) and the United States Environmental Protection Agency (USEPA) to continue our remediation efforts. We estimated that it would take a substantial period of time to complete the groundwater remediation, and the costs through completion were estimated to range from $42 to $52. As no amount within the range was a better estimate than another, we recognized a pretax expense in fiscal 2006 of $42 as a component of income from discontinued operations and recorded an environmental accrual of $42 in continuing operations on the consolidated balance sheets. There has been no change to the estimated exposure range related to the Pace facility. We have implemented many of the remedial corrective measures at the Pace facility required under 1995 Consent Orders issued by the FDEP and the USEPA. Contaminated soils have been bioremediated, and the treated soils have been secured in a lined on-site disposal cell. Several groundwater recovery systems have been installed to contain and remove contamination from groundwater. We completed an extensive assessment of the site to determine how well existing measures are working, what additional corrective measures may be needed, and whether newer remediation technologies that were not available in the 1990s might be suitable to more quickly and effectively remove groundwater contaminants. Based on assessment results, we completed a focused feasibility study that has identified alternative approaches that may more effectively remove contaminants. We continue to review alternative remedial approaches with the FDEP and have started additional field work to support the design of an improved groundwater recovery network with the objective of targeting areas of higher contaminant concentration and avoiding areas of high groundwater iron which has proven to be a significant operability issue for the project. In the first quarter of 2015, we entered into a new Consent Order with the FDEP requiring us to continue our remediation efforts at the Pace facility. The costs we are incurring under the new Consent Order are consistent with our previous estimates. PIEDMONT At 31 March 2018, $16.2 of the environmental accrual was related to the Piedmont site. On 30 June 2008, we sold our Elkton, Maryland, and Piedmont, South Carolina, production facilities and the related North American atmospheric emulsions and global pressure sensitive adhesives businesses. In connection with the sale, we recognized a liability for retained environmental obligations associated with remediation activities at the Piedmont site. This site is under active remediation for contamination caused by an insolvent prior owner. We are required by the South Carolina Department of Health and Environmental Control (SCDHEC) to address both contaminated soil and groundwater. Numerous areas of soil contamination have been addressed, and contaminated groundwater is being recovered and treated. On 13 June 2017, the SCDHEC issued its final approval to the site-wide feasibility study, and with that, we will be moving towards a record of decision for the Piedmont site and into the final remedial design phase of this project. We estimate that source area remediation and groundwater recovery and treatment will continue through 2029. Thereafter, we are expecting this site to go into a state of monitored natural attenuation through 2047. We recognized a pretax expense in 2008 of $24 as a component of income from discontinued operations and recorded an environmental liability of $24 in continuing operations on the consolidated balance sheets. There have been no significant changes to the estimated exposure. PASADENA At 31 March 2018, $11.9 of the environmental accrual was related to the Pasadena site. During the fourth quarter of 2012, management committed to permanently shutting down our polyurethane intermediates (PUI) production facility in Pasadena, Texas. In shutting down and dismantling the facility, we have undertaken certain obligations related to soil and groundwater contaminants. We have been pumping and treating groundwater to control off-site contaminant migration in compliance with regulatory requirements and under the approval of the Texas Commission on Environmental Quality (TCEQ). We estimate that the pump and treat system will continue to operate until 2042. We plan to perform additional work to address other environmental obligations at the site. This additional work includes remediating, as required, impacted soils, investigating groundwater west of the former PUI facility, performing post closure care for two closed RCRA surface impoundment units, and establishing engineering controls. In 2012, we estimated the total exposure at this site to be $13. There have been no significant changes to the estimated exposure. Unconditional Purchase Obligations Our unconditional purchase obligations for helium purchases were approximately $6,500 as of 31 March 2018. The majority of these obligations occur after fiscal year 2022. Helium purchases include crude feedstock supply to multiple helium refining plants in North America as well as refined helium purchases from sources around the world. As a rare byproduct of natural gas production in the energy sector, these helium sourcing agreements are medium- to long-term and contain take-if-tendered provisions. The refined helium is distributed globally and sold as a merchant gas, primarily under medium-term requirements contracts. While contract terms in the energy sector are longer than those in merchant, helium is a rare gas used in applications with few or no substitutions because of its unique physical and chemical properties.

Share-Based Compensation

6 Months Ended

Mar. 31, 2018

Disclosure of Compensation Related Costs, Share-based Payments [Abstract]

Share-Based Compensation

SHARE-BASED COMPENSATION

We have various share-based compensation programs, which include deferred stock units, stock options, and restricted stock. During the six months ended 31 March 2018, we granted market-based and time-based deferred stock units. Under all programs, the terms of the awards are fixed at the grant date. We issue shares from treasury stock upon the payout of deferred stock units, the exercise of stock options, and the issuance of restricted stock awards. As of 31 March 2018, there were 4,610,336 shares available for future grant under our Long-Term Incentive Plan (LTIP), which is shareholder approved.

Share-based compensation cost recognized in continuing operations on the consolidated income statements is summarized below:



	Three Months Ended						Six Months Ended
	31 March						31 March
	2018			2017			2018			2017
Before-tax share-based compensation cost		$10.7			$9.5			$22.5			$18.5
Income tax benefit	(2.1		)	(3.3		)	(5.3		)	(6.3		)
After-tax share-based compensation cost		$8.6			$6.2			$17.2			$12.2

Before-tax share-based compensation cost is primarily included in "Selling and administrative" on our consolidated income statements. The amount of share-based compensation cost capitalized in the first six months of fiscal year 2018 and 2017 was not material.

Deferred Stock Units

During the six months ended 31 March 2018, we granted 104,874 market-based deferred stock units. The market-based deferred stock units are earned out at the end of a performance period beginning 1 October 2017 and ending 30 September 2020, conditioned on the level of the Company’s total shareholder return in relation to a defined peer group over the three-year performance period.

The market-based deferred stock units had an estimated grant-date fair value of $202.50 per unit, which was estimated using a Monte Carlo simulation model. The model utilizes multiple input variables that determine the probability of satisfying the market condition stipulated in the grant and calculates the fair value of the awards. We generally expense the grant-date fair value of these awards on a straight-line basis over the vesting period. The calculation of the fair value of market-based deferred stock units used the following assumptions:



Expected volatility	18.7	%
Risk-free interest rate	1.9	%
Expected dividend yield	2.6	%

In addition, during the six months ended 31 March 2018, we granted 138,340 time-based deferred stock units at a weighted average grant-date fair value of $162.12.

Equity

6 Months Ended

Mar. 31, 2018

Stockholders' Equity Note [Abstract]

Equity

EQUITY

The following is a summary of the changes in total equity:



	Three Months Ended 31 March
	2018									2017
	Air Products			Non- controlling Interests			Total Equity			Air Products			Non- controlling Interests			Total Equity
Balance at 31 December		$10,215.3			$105.9			$10,321.2			$7,161.5			$99.6			$7,261.1
Net income	416.4			7.2			423.6			2,130.0			5.7			2,135.7
Other comprehensive income	160.3			2.2			162.5			218.0			5.0			223.0
Dividends on common stock (per share $1.10, $0.95)	(241.1		)	—			(241.1		)	(206.9		)	—			(206.9		)
Dividends to noncontrolling interests	—			(2.9		)	(2.9		)	—			(7.5		)	(7.5		)
Share-based compensation	10.7			—			10.7			9.5			—			9.5
Treasury shares for stock option and award plans	20.2			—			20.2			7.9			—			7.9
Other equity transactions	(1.0		)	—			(1.0		)	(2.6		)	—			(2.6		)
Balance at 31 March		$10,580.8			$112.4			$10,693.2			$9,317.4			$102.8			$9,420.2




	Six Months Ended 31 March
	2018									2017
	Air Products			Non- controlling Interests			Total Equity			Air Products			Non- controlling Interests			Total Equity
Balance at 30 September		$10,086.2			$99.3			$10,185.5			$7,079.6			$133.8			$7,213.4
Net income	571.0			14.3			585.3			2,429.8			12.3			2,442.1
Other comprehensive income (loss)	312.1			4.1			316.2			(16.9		)	1.9			(15.0		)
Dividends on common stock (per share $2.05, $1.81)	(449.1		)	—			(449.1		)	(394.0		)	—			(394.0		)
Dividends to noncontrolling interests	—			(10.6		)	(10.6		)	—			(11.7		)	(11.7		)
Share-based compensation	21.8			—			21.8			18.5			—			18.5
Treasury shares for stock option and award plans	40.1			—			40.1			7.6			—			7.6
Spin-off of Versum	—			—			—			186.5			(33.9		)	152.6
Cumulative change in accounting principle	—			—			—			8.8			—			8.8
Other equity transactions	(1.3		)	5.3			4.0			(2.5		)	.4			(2.1		)
Balance at 31 March		$10,580.8			$112.4			$10,693.2			$9,317.4			$102.8			$9,420.2

Accumulated Other Comprehensive Loss

6 Months Ended

Mar. 31, 2018

Accumulated Other Comprehensive Income (Loss), Net of Tax [Abstract]

Accumulated Other Comprehensive Loss

ACCUMULATED OTHER COMPREHENSIVE LOSS

The tables below summarize changes in accumulated other comprehensive loss (AOCL), net of tax, attributable to Air Products for the three and six months ended 31 March 2018:



	Derivatives qualifying as hedges			Foreign currency translation adjustments			Pension and postretirement benefits			Total
Balance at 31 December 2017		($61.8	)		($649.5	)		($984.3	)		($1,695.6	)
Other comprehensive income before reclassifications	17.8			125.6			—			143.4
Amounts reclassified from AOCL	(7.5		)	—			26.6			19.1
Net current period other comprehensive income	10.3			125.6			26.6			162.5
Amount attributable to noncontrolling interests	(.1		)	2.3			—			2.2
Balance at 31 March 2018		($51.4	)		($526.2	)		($957.7	)		($1,535.3	)




	Derivatives qualifying as hedges			Foreign currency translation adjustments			Pension and postretirement benefits			Total
Balance at 30 September 2017		($53.1	)		($787.1	)		($1,007.2	)		($1,847.4	)
Other comprehensive income before reclassifications	8.3			262.0			—			270.3
Amounts reclassified from AOCL	(6.7		)	3.1			49.5			45.9
Net current period other comprehensive income	1.6			265.1			49.5			316.2
Amount attributable to noncontrolling interests	(.1		)	4.2			—			4.1
Balance at 31 March 2018		($51.4	)		($526.2	)		($957.7	)		($1,535.3	)

The table below summarizes the reclassifications out of accumulated other comprehensive loss and the affected line item on the consolidated income statements:



	Three Months Ended						Six Months Ended
	31 March						31 March
	2018			2017			2018			2017
(Gain) Loss on Cash Flow Hedges, net of tax
Sales/Cost of sales		$4.0			$1.2			$5.0			$5.8
Other income/expense, net	(13.8		)	5.5			(15.2		)	26.6
Interest expense	2.3			(.9		)	3.5			(1.0		)
Total (Gain) Loss on Cash Flow Hedges, net of tax		($7.5	)		$5.8			($6.7	)		$31.4
Currency Translation Adjustment^(A)		$—			$49.1			$3.1			$49.1
Pension and Postretirement Benefits, net of tax^(B)		$26.6			$30.1			$49.5			$57.5


^(A)	The 2018 impact is reflected in "Cost of sales" and relates to an equipment sale resulting from the termination of a contract in the Industrial Gases – Asia segment during the first quarter. The 2017 impact was reflected in "Income from discontinued operations, net of tax" and related to the sale of PMD during the second quarter.

^(B)

The components of net periodic benefit cost reclassified out of accumulated other comprehensive loss include items such as prior service cost amortization, actuarial loss amortization, and settlements and are included in “Other non-operating income (expense), net” on the consolidated income statements. Refer to Note 11, Retirement Benefits, for additional information.

Earnings per Share

6 Months Ended

Mar. 31, 2018

Earnings Per Share [Abstract]

Earnings per Share

EARNINGS PER SHARE

The following table sets forth the computation of basic and diluted earnings per share:



	Three Months Ended				Six Months Ended
	31 March				31 March
	2018		2017		2018			2017
Numerator
Income from continuing operations		$416.4		$304.4		$572.0			$556.0
Income (Loss) from discontinued operations	—		1,825.6		(1.0		)	1,873.8
Net Income Attributable to Air Products		$416.4		$2,130.0		$571.0			$2,429.8
Denominator (in millions)
Weighted average common shares — Basic	219.4		217.9		219.2			217.8
Effect of dilutive securities
Employee stock option and other award plans	1.4		1.8		1.5			1.8
Weighted average common shares — Diluted	220.8		219.7		220.7			219.6
Basic Earnings Per Common Share Attributable to Air Products
Income from continuing operations		$1.90		$1.40		$2.61			$2.55
Income from discontinued operations	—		8.38		—			8.61
Net Income Attributable to Air Products		$1.90		$9.78		$2.61			$11.16
Diluted Earnings Per Common Share Attributable to Air Products
Income from continuing operations		$1.89		$1.39		$2.59			$2.53
Income from discontinued operations	—		8.31		—			8.53
Net Income Attributable to Air Products		$1.89		$9.70		$2.59			$11.06

Outstanding share-based awards of .1 million shares were antidilutive and therefore excluded from the computation of diluted earnings per share for the three and six months ended 31 March 2018. For the three months ended 31 March 2017, there were no antidilutive outstanding share-based awards. Outstanding share-based awards of .1 million shares were antidilutive and therefore excluded from the computation of diluted earnings per share for the six months ended 31 March 2017.

Income Taxes	6 Months Ended
Income Taxes	Mar. 31, 2018
Income Tax Disclosure [Abstract]
Income Taxes	INCOME TAXES Tax Restructuring Benefit In the second quarter of 2018, we recognized a $38.8 tax benefit, net of reserves for uncertain tax positions, and a decrease in net deferred tax liabilities resulting from the restructuring of foreign subsidiaries. U.S. Tax Cuts and Jobs Act On 22 December 2017, the United States enacted the Tax Act which significantly changed existing U.S. tax laws, including a reduction in the federal corporate income tax rate from 35% to 21%, a deemed repatriation tax on unremitted foreign earnings, as well as other changes. As a result of the Tax Act, our consolidated income statements for the six months ended 31 March 2018 reflect a net expense of $239.0 for the impacts recorded during the first quarter of fiscal year 2018. This includes an expense of $453.0 for the cost of the deemed repatriation tax and adjustments to the future cost of repatriation from foreign investments. This expense impacted our income tax provision by $420.5 and equity affiliate income by $32.5 for future costs of repatriation that will be borne by an equity affiliate. In addition, the income tax provision was benefited by $214.0 primarily from the re-measurement of our net U.S. deferred tax liabilities at the lower corporate tax rate. The $420.5 adjustment reflects a deemed repatriation tax of $364.1 that is payable over eight years and $56.4 resulting primarily from withholding taxes that were established for repatriation of foreign earnings and other impacts of the Tax Act. We expect to apply $53.8 of existing foreign tax credits towards the $364.1 deemed repatriation tax. Of the remaining $310.3 obligation, $263.4 is recorded on our consolidated balance sheets in noncurrent liabilities. We are reporting the impacts of the Tax Act provisionally based upon reasonable estimates as of 31 March 2018. The impacts are not yet finalized as they are dependent on factors and analysis not yet known or fully completed, including but not limited to, the final cash balances for fiscal year 2018, further book to U.S. tax adjustments for the earnings of foreign entities, the issuance of additional guidance, as well as our ongoing analysis of the Tax Act. As a fiscal year-end taxpayer, certain provisions of the Tax Act become effective in our fiscal year 2018 while other provisions do not become effective until fiscal year 2019. The corporate tax rate reduction is effective as of 1 January 2018 and, accordingly, reduces our 2018 fiscal year U.S. federal statutory rate to a blended rate of approximately 24.5%. Primarily due to the net impact of the Tax Act and the restructuring benefit, our effective tax rate was 37.2% for the six months ended 31 March 2018. Cash Paid for Taxes (Net of Cash Refunds) On a total company basis, income tax payments, net of refunds, were $153.7 and $784.7 for the six months ended 31 March 2018 and 2017, respectively. The prior year includes tax payments related to the gain on the sale of the PMD business. Unrecognized Tax Benefits The consolidated balance sheets as of 31 March 2018 and 30 September 2017 include unrecognized tax benefits of $156.9 and $146.4, respectively. The increase from the prior year primarily resulted from additions for current year tax positions of $18.7 and included uncertain tax positions from the restructuring of foreign subsidiaries and reserves for ongoing transfer pricing uncertainties. This was offset by net reductions for tax positions of prior years of $9.7, primarily related to the settlement of U.S. federal tax audits for 2012 through 2014. On 17 April 2018, we received a final audit settlement agreement that resolved uncertainties related to approximately $40 of unrecognized tax benefits that were recorded as of 31 March 2018. This settlement primarily related to tax positions taken in conjunction with the disposition of our Homecare business in 2012. As a result, we expect an income tax benefit of approximately $25, including interest, in discontinued operations during the third quarter of 2018. In addition, the settlement will result in an income tax benefit of approximately $9, including interest, in continuing operations during the third quarter of 2018 for the release of tax reserves on other matters.

Business Segment Information

6 Months Ended

Mar. 31, 2018

Segment Reporting [Abstract]

Business Segment Information

BUSINESS SEGMENT INFORMATION

Our reporting segments reflect the manner in which our chief operating decision maker reviews results and allocates resources. Except in the Corporate and other segment, each reporting segment meets the definition of an operating segment and does not include the aggregation of multiple operating segments. Our liquefied natural gas (LNG) and helium storage and distribution sale of equipment businesses are aggregated within the Corporate and other segment.

Our reporting segments are:


•	Industrial Gases – Americas


•	Industrial Gases – EMEA (Europe, Middle East, and Africa)


•	Industrial Gases – Asia


•	Industrial Gases – Global


•	Corporate and other



	Industrial Gases – Americas		Industrial Gases – EMEA		Industrial Gases – Asia		Industrial Gases – Global		Corporate and other			Segment Total
Three Months Ended 31 March 2018
Sales		$913.2		$561.6		$557.6		$101.7		$21.6			$2,155.7
Operating income (loss)	222.3		116.7		148.7		12.1		(44.4		)	455.4
Depreciation and amortization	122.3		50.7		62.6		1.9		2.5			240.0
Equity affiliates' income	16.9		11.1		15.4		.3		—			43.7
Three Months Ended 31 March 2017
Sales		$890.1		$414.2		$435.9		$216.5		$23.4			$1,980.1
Operating income (loss)	223.2		88.6		112.3		22.7		(40.9		)	405.9
Depreciation and amortization	116.0		41.6		49.3		1.7		3.2			211.8
Equity affiliates' income	13.0		8.3		12.9		—		—			34.2




	Industrial Gases – Americas		Industrial Gases – EMEA		Industrial Gases – Asia		Industrial Gases – Global		Corporate and other			Segment Total
Six Months Ended 31 March 2018
Sales		$1,823.0		$1,077.5		$1,201.2		$234.7		$35.9			$4,372.3
Operating income (loss)	439.5		221.2		324.2		21.6		(90.4		)	916.1
Depreciation and amortization	240.1		99.8		119.4		3.5		5.1			467.9
Equity affiliates' income	35.5		24.2		29.6		.7		—			90.0
Six Months Ended 31 March 2017
Sales		$1,754.0		$813.9		$874.2		$364.4		$56.1			$3,862.6
Operating income (loss)	446.5		178.6		230.7		30.9		(70.0		)	816.7
Depreciation and amortization	227.8		83.8		96.0		3.7		6.6			417.9
Equity affiliates' income	27.7		17.8		26.4		.3		—			72.2
Total Assets
31 March 2018		$5,915.0		$3,475.5		$4,779.1		$252.5		$4,089.0			$18,511.1
30 September 2017	5,840.8		3,276.1		4,412.1		279.6		4,648.4			18,457.0

The sales information noted above relates to external customers only. All intersegment sales are eliminated in consolidation. For the three and six months ended 31 March 2018, the Industrial Gases – Global segment had intersegment sales of $56.0 and $117.9, respectively. For the three and six months ended 31 March 2017, the Industrial Gases – Global segment had intersegment sales of $61.0 and $122.0, respectively. These sales are generally transacted at market pricing. For all other segments, intersegment sales are not material for all periods presented. Equipment manufactured for our industrial gases segments is generally transferred at cost and not reflected as an intersegment sale.

Changes in estimates on projects accounted for under the percentage-of-completion method favorably impacted operating income by approximately $10 and $12 for the three months ended 31 March 2018 and 2017, respectively.

In 2015, we entered into a long-term sale of equipment contract to engineer, procure, and construct industrial gas facilities with a 25%-owned joint venture for Saudi Aramco's Jazan oil refinery and power plant in Saudi Arabia. Sales related to this contract are included in the results of our Industrial Gases – Global segment. During the three and six months ended 31 March 2018, sales were approximately $60 and $150, respectively, related to this contract. During the three and six months ended 31 March 2017, sales were approximately $170 and $280, respectively.

Below is a reconciliation of segment total operating income to consolidated operating income:



	Three Months Ended					Six Months Ended
	31 March					31 March
Operating Income	2018		2017			2018		2017
Segment total		$455.4		$405.9			$916.1		$816.7
Business separation costs	—		—			—		(32.5		)
Cost reduction and asset actions	—		(10.3		)	—		(60.3		)
Consolidated Total		$455.4		$395.6			$916.1		$723.9

Below is a reconciliation of segment total equity affiliates' income to consolidated equity affiliates' income:



	Three Months Ended				Six Months Ended
	31 March				31 March
Equity Affiliates' Income	2018		2017		2018			2017
Segment total		$43.7		$34.2		$90.0			$72.2
Tax reform repatriation - equity method investment	—		—		(32.5		)	—
Consolidated Total		$43.7		$34.2		$57.5			$72.2

Below is a reconciliation of segment total assets to consolidated total assets:



	31 March		30 September
Total Assets	2018		2017
Segment total		$18,511.1		$18,457.0
Discontinued operations	—		10.2
Consolidated Total		$18,511.1		$18,467.2

Discontinued Operations (Tables)

6 Months Ended

Mar. 31, 2018

Discontinued Operations and Disposal Groups [Abstract]

Schedule of Operating Results of Discontinued Operations



	Three Months Ended
	31 March 2017
							Total
	Performance			Energy-			Discontinued
	Materials			from-Waste^(A)			Operations
Cost of sales		$3.3			$3.0			$6.3
Selling and administrative	2.1			—			2.1
Other income (expense), net	.7			(.4		)	.3
Income (Loss) Before Taxes	(4.7		)	(3.4		)	(8.1		)
Income tax benefit	(.3		)	(.9		)	(1.2		)
Income (Loss) From Operations of Discontinued Operations, net of tax	(4.4		)	(2.5		)	(6.9		)
Gain on Disposal, net of tax	1,832.5			—			1,832.5
Income (Loss) From Discontinued Operations, net of tax		$1,828.1			($2.5	)		$1,825.6




	Six Months Ended
	31 March 2017
							Total
	Performance			Energy-			Discontinued
	Materials			from-Waste^(A)			Operations
Sales		$254.8			$—			$254.8
Cost of sales	182.3			9.6			191.9
Selling and administrative	22.5			.2			22.7
Research and development	5.1			—			5.1
Other income (expense), net	.3			(.1		)	.2
Operating Income (Loss)	45.2			(9.9		)	35.3
Equity affiliates’ income	.3			—			.3
Income (Loss) Before Taxes	45.5			(9.9		)	35.6
Income tax benefit^(B)	(50.8		)	(2.0		)	(52.8		)
Income (Loss) From Operations of Discontinued Operations, net of tax	96.3			(7.9		)	88.4
Gain (Loss) on Disposal, net of tax	1,832.5			(47.1		)	1,785.4
Income (Loss) From Discontinued Operations, net of tax		$1,928.8			($55.0	)		$1,873.8


^(A)	The loss from operations of discontinued operations for EfW primarily relates to land lease obligations, administrative costs, and costs incurred for project exit activities.


^(B)	As a result of the expected gain on the sale of PMD, we released valuation allowances related to capital loss and net operating loss carryforwards during the first quarter of 2017 that favorably impacted our income tax provision within discontinued operations by approximately $66.

- Definition

Tabular disclosure of information related to a disposal group. Includes, but is not limited to, a discontinued operation, disposal classified as held-for-sale or disposed of by means other than sale or disposal of an individually significant component.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 205
-SubTopic 20
-Section 45
-Paragraph 11
-URI http://asc.fasb.org/extlink&oid=65878427&loc=SL51721533-107759

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 205
-SubTopic 20
-Section 50
-Paragraph 4B
-URI http://asc.fasb.org/extlink&oid=64827811&loc=SL51721665-107760

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 205
-SubTopic 20
-Section 50
-Paragraph 3
-URI http://asc.fasb.org/extlink&oid=64827811&loc=d3e1474-107760

Reference 4: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 205
-SubTopic 20
-Section 50
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=64827811&loc=d3e1361-107760

Reference 5: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 205
-SubTopic 20
-Section 50
-Paragraph 7
-URI http://asc.fasb.org/extlink&oid=64827811&loc=SL51721683-107760

Reference 6: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 360
-SubTopic 10
-Section 50
-Paragraph 3A
-URI http://asc.fasb.org/extlink&oid=84176398&loc=SL51724579-110230

Reference 7: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 205
-SubTopic 20
-Section 50
-Paragraph 5C
-URI http://asc.fasb.org/extlink&oid=64827811&loc=SL51721675-107760

Reference 8: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 205
-SubTopic 20
-Section 50
-Paragraph 4A
-URI http://asc.fasb.org/extlink&oid=64827811&loc=SL51721663-107760

Reference 9: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 360
-SubTopic 10
-Section 50
-Paragraph 3
-URI http://asc.fasb.org/extlink&oid=84176398&loc=d3e2941-110230

Reference 10: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 205
-SubTopic 20
-Section 50
-Paragraph 5B
-URI http://asc.fasb.org/extlink&oid=64827811&loc=SL51721673-107760

Reference 11: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 205
-SubTopic 20
-Section 50
-Paragraph 3A
-URI http://asc.fasb.org/extlink&oid=64827811&loc=SL51721659-107760

Reference 12: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 205
-SubTopic 20
-Section 50
-Paragraph 5A
-URI http://asc.fasb.org/extlink&oid=64827811&loc=SL51721671-107760

Reference 13: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 205
-SubTopic 20
-Section 50
-Paragraph 5D
-URI http://asc.fasb.org/extlink&oid=64827811&loc=SL51721677-107760

+ Details

Cost Reduction and Asset Actions (Tables)

6 Months Ended

Mar. 31, 2018

Restructuring and Related Activities [Abstract]

Summary of Carrying Amount of Accrual for Cost Reduction and Asset Actions

The following table summarizes the carrying amount of the accrual for cost reduction and asset actions at 31 March 2018:



	Severance and Other Benefits			Asset Actions/Other			Total
30 September 2016		$12.3			$—			$12.3
2017 Charge	66.3			88.5			154.8
Noncash expenses	—			(84.2		)	(84.2		)
Amount reflected in pension liability	(2.0		)	—			(2.0		)
Amount reflected in other noncurrent liabilities	—			(2.2		)	(2.2		)
Cash expenditures	(35.7		)	(1.2		)	(36.9		)
Currency translation adjustment	(.3		)	—			(.3		)
30 September 2017		$40.6			$.9			$41.5
Amount reflected in pension liability	(.4		)	—			(.4		)
Cash expenditures	(23.9		)	(.2		)	(24.1		)
Currency translation adjustment	.7			—			.7
31 March 2018		$17.0			$.7			$17.7

Inventories (Tables)

6 Months Ended

Mar. 31, 2018

Inventory Disclosure [Abstract]

Schedule of Inventory

The components of inventories are as follows:



	31 March			30 September
	2018			2017
Finished goods		$134.3			$120.0
Work in process	16.1			15.7
Raw materials, supplies and other	213.6			223.0
Total FIFO cost		$364.0			$358.7
Less: Excess of FIFO cost over LIFO cost	(24.1		)	(23.3		)
Inventories		$339.9			$335.4

Goodwill (Tables)

6 Months Ended

Mar. 31, 2018

Goodwill and Intangible Assets Disclosure [Abstract]

Schedule of Goodwill

Changes to the carrying amount of consolidated goodwill by segment for the six months ended 31 March 2018 are as follows:



	Industrial Gases– Americas		Industrial Gases– EMEA		Industrial Gases– Asia		Industrial Gases– Global		Total
Goodwill, net at 30 September 2017		$163.7		$402.4		$135.2		$20.2		$721.5
Acquisitions	—		27.7		35.2		—		62.9
Currency translation	3.5		22.0		5.0		.1		30.6
Goodwill, net at 31 March 2018		$167.2		$452.1		$175.4		$20.3		$815.0



	31 March			30 September
	2018			2017
Goodwill, gross		$1,257.0			$1,138.7
Accumulated impairment losses	(442.0		)	(417.2		)
Goodwill, net		$815.0			$721.5

Financial Instruments (Tables)

6 Months Ended

Mar. 31, 2018

Derivative Instruments and Hedging Activities Disclosure [Abstract]

Schedule of Notional Amounts of Outstanding Derivative Instruments

The table below summarizes our outstanding currency price risk management instruments:



	31 March 2018			30 September 2017
	US$ Notional		Years Average Maturity	US$ Notional		Years Average Maturity
Forward Exchange Contracts:
Cash flow hedges		$2,953.8	.4		$3,150.2	.4
Net investment hedges	369.5		2.5	675.5		3.0
Not designated	990.0		1.7	273.8		.1
Total Forward Exchange Contracts		$4,313.3	.9		$4,099.5	.8

The following table summarizes our outstanding interest rate management contracts and cross currency interest rate swaps:



	31 March 2018							30 September 2017
	US$ Notional		Average Pay %		Average Receive %		Years Average Maturity	US$ Notional		Average Pay %		Average Receive %		Years Average Maturity
Interest rate swaps (fair value hedge)		$400.0	LIBOR		2.53	%	1.4		$600.0	LIBOR		2.28	%	1.3
Cross currency interest rate swaps (net investment hedge)		$688.7	3.73	%	2.76	%	2.3		$539.7	3.27	%	2.59	%	1.9
Cross currency interest rate swaps (cash flow hedge)		$1,014.6	5.01	%	2.75	%	2.4		$1,095.7	4.96	%	2.78	%	2.4
Cross currency interest rate swaps (not designated)		$39.5	3.16	%	2.88	%	1.5		$41.6	3.28	%	2.32	%	1.7

Fair Value of Derivative Instruments

The table below summarizes the fair value and balance sheet location of our outstanding derivatives:



	Balance Sheet Location	31 March 2018		30 September 2017		Balance Sheet Location	31 March 2018		30 September 2017
Derivatives Designated as Hedging Instruments:
Forward exchange contracts	Other receivables		$81.7		$81.7	Accrued liabilities		$31.6		$82.0
Interest rate management contracts	Other receivables	5.5		11.1		Accrued liabilities	19.4		10.7
Forward exchange contracts	Other noncurrent assets	9.1		27.1		Other noncurrent liabilities	19.7		13.8
Interest rate management contracts	Other noncurrent assets	43.5		102.6		Other noncurrent liabilities	58.1		22.2
Total Derivatives Designated as Hedging Instruments			$139.8		$222.5			$128.8		$128.7
Derivatives Not Designated as Hedging Instruments:
Forward exchange contracts	Other receivables		$4.4		$1.1	Accrued liabilities		$5.4		$2.2
Interest rate management contracts	Other receivables	—		—		Accrued liabilities	.4		1.0
Forward exchange contracts	Other noncurrent assets	9.5		—		Other noncurrent liabilities	17.0		—
Interest rate management contracts	Other noncurrent assets	3.9		4.2		Other noncurrent liabilities	—		—
Total Derivatives Not Designated as Hedging Instruments			$17.8		$5.3			$22.8		$3.2
Total Derivatives			$157.6		$227.8			$151.6		$131.9

Schedule of Gains and Losses Related to Derivative Instruments

The table below summarizes the gain or loss related to our cash flow hedges, fair value hedges, net investment hedges, and derivatives not designated as hedging instruments:



	Three Months Ended 31 March
	Forward Exchange Contracts						Foreign Currency Debt						Other ^(A)						Total
	2018			2017			2018			2017			2018			2017			2018			2017
Cash Flow Hedges, net of tax:
Net gain (loss) recognized in OCI (effective portion)		$31.9			$11.1			$—			$—			($14.1	)		($26.5	)		$17.8			($15.4	)
Net (gain) loss reclassified from OCI to sales/cost of sales (effective portion)	4.0			1.2			—			—			—			—			4.0			1.2
Net (gain) loss reclassified from OCI to other income (expense), net (effective portion)	(29.3		)	(10.8		)	—			—			15.8			15.8			(13.5		)	5.0
Net (gain) loss reclassified from OCI to interest expense (effective portion)	1.6			(1.6		)	—			—			.7			.7			2.3			(.9		)
Net (gain) loss reclassified from OCI to other income (expense), net (ineffective portion)	(.3		)	.5			—			—			—			—			(.3		)	.5
Fair Value Hedges:
Net gain (loss) recognized in interest expense^(B)		$—			$—			$—			$—			($3.6	)		($2.8	)		($3.6	)		($2.8	)
Net Investment Hedges, net of tax:
Net gain (loss) recognized in OCI		($15.2	)		($.8	)		($22.2	)		($7.8	)		($23.3	)		($6.5	)		($60.7	)		($15.1	)
Derivatives Not Designated as Hedging Instruments:
Net gain (loss) recognized in other income (expense), net^(C)		$1.6			($2.5	)		$—			$—			($2.2	)		($.6	)		($.6	)		($3.1	)




	Six Months Ended 31 March
	Forward Exchange Contracts						Foreign Currency Debt					Other ^(A)						Total
	2018			2017			2018			2017		2018			2017			2018			2017
Cash Flow Hedges, net of tax:
Net gain (loss) recognized in OCI (effective portion)		$39.4			($48.3	)		$—			$—		($31.1	)		$23.1			$8.3			($25.2	)
Net (gain) loss reclassified from OCI to sales/cost of sales (effective portion)	5.0			5.8			—			—		—			—			5.0			5.8
Net (gain) loss reclassified from OCI to other income (expense), net (effective portion)	(46.9		)	38.7			—			—		32.2			(12.4		)	(14.7		)	26.3
Net (gain) loss reclassified from OCI to interest expense (effective portion)	2.2			(2.4		)	—			—		1.3			1.4			3.5			(1.0		)
Net (gain) loss reclassified from OCI to other income (expense), net (ineffective portion)	(.5		)	.3			—			—		—			—			(.5		)	.3
Fair Value Hedges:
Net gain (loss) recognized in interest expense^(B)		$—			$—			$—			$—		($6.8	)		($11.9	)		($6.8	)		($11.9	)
Net Investment Hedges, net of tax:
Net gain (loss) recognized in OCI		($22.7	)		$27.1			($39.5	)		$34.0		($34.5	)		$6.6			($96.7	)		$67.7
Derivatives Not Designated as Hedging Instruments:
Net gain (loss) recognized in other income (expense), net^(C)		$.1			($.4	)		$—			$—		($3.5	)		$.2			($3.4	)		($.2	)


^(A)	Other includes the impact on other comprehensive income (OCI) and earnings primarily related to interest rate and cross currency interest rate swaps.


^(B)	The impact of fair value hedges noted above was largely offset by recognized gains and losses resulting from the impact of changes in related interest rates on outstanding debt.

^(C)

The impact of the non-designated hedges noted above was largely offset by recognized gains and losses resulting from the impact of changes in exchange rates on assets and liabilities denominated in non-functional currencies.

Fair Value Measurements (Tables)

6 Months Ended

Mar. 31, 2018

Fair Value Disclosures [Abstract]

Schedule of Carrying Value and Fair Value of Financial Instruments

The carrying values and fair values of financial instruments were as follows:



	31 March 2018				30 September 2017
	Carrying Value		Fair Value		Carrying Value		Fair Value
Assets
Derivatives
Forward exchange contracts		$104.7		$104.7		$109.9		$109.9
Interest rate management contracts	52.9		52.9		117.9		117.9
Liabilities
Derivatives
Forward exchange contracts		$73.7		$73.7		$98.0		$98.0
Interest rate management contracts	77.9		77.9		33.9		33.9
Long-term debt, including current portion	3,454.0		3,459.5		3,818.8		3,928.2

Schedule of Fair Value Assets and Liabilities Measured On Recurring Basis

The following table summarizes assets and liabilities measured at fair value on a recurring basis in the consolidated balance sheets:



	31 March 2018								30 September 2017
	Total		Level 1		Level 2		Level 3		Total		Level 1		Level 2		Level 3
Assets at Fair Value
Derivatives
Forward exchange contracts		$104.7		$—		$104.7		$—		$109.9		$—		$109.9		$—
Interest rate management contracts	52.9		—		52.9		—		117.9		—		117.9		—
Total Assets at Fair Value		$157.6		$—		$157.6		$—		$227.8		$—		$227.8		$—
Liabilities at Fair Value
Derivatives
Forward exchange contracts		$73.7		$—		$73.7		$—		$98.0		$—		$98.0		$—
Interest rate management contracts	77.9		—		77.9		—		33.9		—		33.9		—
Total Liabilities at Fair Value		$151.6		$—		$151.6		$—		$131.9		$—		$131.9		$—

Retirement Benefits (Tables)

6 Months Ended

Mar. 31, 2018

Retirement Benefits [Abstract]

Schedule of Net Periodic Benefit Cost

The components of net periodic benefit cost for the defined benefit pension plans for the three and six months ended 31 March 2018 and 2017 were as follows:



	Pension Benefits
	2018						2017
Three Months Ended 31 March	U.S.			International			U.S.			International
Service cost		$6.4			$6.6			$6.9			$6.3
Interest cost	26.8			9.6			27.6			7.9
Expected return on plan assets	(50.4		)	(21.1		)	(51.7		)	(18.3		)
Prior service cost amortization	.4			—			.6			(.1		)
Actuarial loss amortization	22.2			10.3			20.9			13.2
Settlements	1.5			—			4.1			4.0
Curtailment	—			—			.1			1.8
Special termination benefits	.4			—			(.1		)	.1
Other	—			.1			—			(2.2		)
Net Periodic Benefit Cost (Total)		$7.3			$5.5			$8.4			$12.7
Less: Discontinued Operations	—			—			(.1		)	(3.4		)
Net Periodic Benefit Cost (Continuing Operations)		$7.3			$5.5			$8.3			$9.3




	Pension Benefits
	2018						2017
Six Months Ended 31 March	U.S.			International			U.S.			International
Service cost^(A)		$12.8			$12.9			$15.2			$13.0
Interest cost	53.5			18.8			52.5			15.5
Expected return on plan assets	(100.8		)	(41.3		)	(104.4		)	(36.8		)
Prior service cost amortization	.8			—			1.2			(.1		)
Actuarial loss amortization	43.9			20.3			47.0			27.1
Settlements	3.3			—			4.1			1.7
Curtailment	—			—			4.3			(1.3		)
Special termination benefits	.4			—			1.0			.5
Other	—			.6			—			.5
Net Periodic Benefit Cost (Total)		$13.9			$11.3			$20.9			$20.1
Less: Discontinued Operations	—			—			(.7		)	(4.1		)
Net Periodic Benefit Cost (Continuing Operations)		$13.9			$11.3			$20.2			$16.0

^(A)

Includes total service costs from discontinued operations of $1.3 for the six months ended 31 March 2017.

Share-Based Compensation (Tables)

6 Months Ended

Mar. 31, 2018

Disclosure of Compensation Related Costs, Share-based Payments [Abstract]

Schedule of Recognized Share-Based Compensation Cost

Share-based compensation cost recognized in continuing operations on the consolidated income statements is summarized below:



	Three Months Ended						Six Months Ended
	31 March						31 March
	2018			2017			2018			2017
Before-tax share-based compensation cost		$10.7			$9.5			$22.5			$18.5
Income tax benefit	(2.1		)	(3.3		)	(5.3		)	(6.3		)
After-tax share-based compensation cost		$8.6			$6.2			$17.2			$12.2

Schedule of Assumptions for Fair Value of Market-Based Deferred Stock Units

The calculation of the fair value of market-based deferred stock units used the following assumptions:



Expected volatility	18.7	%
Risk-free interest rate	1.9	%
Expected dividend yield	2.6	%

Equity (Tables)

6 Months Ended

Mar. 31, 2018

Stockholders' Equity Note [Abstract]

Schedule of Equity

The following is a summary of the changes in total equity:



	Three Months Ended 31 March
	2018									2017
	Air Products			Non- controlling Interests			Total Equity			Air Products			Non- controlling Interests			Total Equity
Balance at 31 December		$10,215.3			$105.9			$10,321.2			$7,161.5			$99.6			$7,261.1
Net income	416.4			7.2			423.6			2,130.0			5.7			2,135.7
Other comprehensive income	160.3			2.2			162.5			218.0			5.0			223.0
Dividends on common stock (per share $1.10, $0.95)	(241.1		)	—			(241.1		)	(206.9		)	—			(206.9		)
Dividends to noncontrolling interests	—			(2.9		)	(2.9		)	—			(7.5		)	(7.5		)
Share-based compensation	10.7			—			10.7			9.5			—			9.5
Treasury shares for stock option and award plans	20.2			—			20.2			7.9			—			7.9
Other equity transactions	(1.0		)	—			(1.0		)	(2.6		)	—			(2.6		)
Balance at 31 March		$10,580.8			$112.4			$10,693.2			$9,317.4			$102.8			$9,420.2




	Six Months Ended 31 March
	2018									2017
	Air Products			Non- controlling Interests			Total Equity			Air Products			Non- controlling Interests			Total Equity
Balance at 30 September		$10,086.2			$99.3			$10,185.5			$7,079.6			$133.8			$7,213.4
Net income	571.0			14.3			585.3			2,429.8			12.3			2,442.1
Other comprehensive income (loss)	312.1			4.1			316.2			(16.9		)	1.9			(15.0		)
Dividends on common stock (per share $2.05, $1.81)	(449.1		)	—			(449.1		)	(394.0		)	—			(394.0		)
Dividends to noncontrolling interests	—			(10.6		)	(10.6		)	—			(11.7		)	(11.7		)
Share-based compensation	21.8			—			21.8			18.5			—			18.5
Treasury shares for stock option and award plans	40.1			—			40.1			7.6			—			7.6
Spin-off of Versum	—			—			—			186.5			(33.9		)	152.6
Cumulative change in accounting principle	—			—			—			8.8			—			8.8
Other equity transactions	(1.3		)	5.3			4.0			(2.5		)	.4			(2.1		)
Balance at 31 March		$10,580.8			$112.4			$10,693.2			$9,317.4			$102.8			$9,420.2

Accumulated Other Comprehensive Loss (Tables)

6 Months Ended

Mar. 31, 2018

Accumulated Other Comprehensive Income (Loss), Net of Tax [Abstract]

Schedule of Accumulated Other Comprehensive Income (Loss)

The tables below summarize changes in accumulated other comprehensive loss (AOCL), net of tax, attributable to Air Products for the three and six months ended 31 March 2018:



	Derivatives qualifying as hedges			Foreign currency translation adjustments			Pension and postretirement benefits			Total
Balance at 31 December 2017		($61.8	)		($649.5	)		($984.3	)		($1,695.6	)
Other comprehensive income before reclassifications	17.8			125.6			—			143.4
Amounts reclassified from AOCL	(7.5		)	—			26.6			19.1
Net current period other comprehensive income	10.3			125.6			26.6			162.5
Amount attributable to noncontrolling interests	(.1		)	2.3			—			2.2
Balance at 31 March 2018		($51.4	)		($526.2	)		($957.7	)		($1,535.3	)




	Derivatives qualifying as hedges			Foreign currency translation adjustments			Pension and postretirement benefits			Total
Balance at 30 September 2017		($53.1	)		($787.1	)		($1,007.2	)		($1,847.4	)
Other comprehensive income before reclassifications	8.3			262.0			—			270.3
Amounts reclassified from AOCL	(6.7		)	3.1			49.5			45.9
Net current period other comprehensive income	1.6			265.1			49.5			316.2
Amount attributable to noncontrolling interests	(.1		)	4.2			—			4.1
Balance at 31 March 2018		($51.4	)		($526.2	)		($957.7	)		($1,535.3	)

Schedule of Reclassification out of Accumulated Other Comprehensive Income (Loss)

The table below summarizes the reclassifications out of accumulated other comprehensive loss and the affected line item on the consolidated income statements:



	Three Months Ended						Six Months Ended
	31 March						31 March
	2018			2017			2018			2017
(Gain) Loss on Cash Flow Hedges, net of tax
Sales/Cost of sales		$4.0			$1.2			$5.0			$5.8
Other income/expense, net	(13.8		)	5.5			(15.2		)	26.6
Interest expense	2.3			(.9		)	3.5			(1.0		)
Total (Gain) Loss on Cash Flow Hedges, net of tax		($7.5	)		$5.8			($6.7	)		$31.4
Currency Translation Adjustment^(A)		$—			$49.1			$3.1			$49.1
Pension and Postretirement Benefits, net of tax^(B)		$26.6			$30.1			$49.5			$57.5


^(A)	The 2018 impact is reflected in "Cost of sales" and relates to an equipment sale resulting from the termination of a contract in the Industrial Gases – Asia segment during the first quarter. The 2017 impact was reflected in "Income from discontinued operations, net of tax" and related to the sale of PMD during the second quarter.

^(B)

Earnings per Share (Tables)

6 Months Ended

Mar. 31, 2018

Earnings Per Share [Abstract]

Schedule of Computation of Basic and Diluted Earnings Per Share

The following table sets forth the computation of basic and diluted earnings per share:



	Three Months Ended				Six Months Ended
	31 March				31 March
	2018		2017		2018			2017
Numerator
Income from continuing operations		$416.4		$304.4		$572.0			$556.0
Income (Loss) from discontinued operations	—		1,825.6		(1.0		)	1,873.8
Net Income Attributable to Air Products		$416.4		$2,130.0		$571.0			$2,429.8
Denominator (in millions)
Weighted average common shares — Basic	219.4		217.9		219.2			217.8
Effect of dilutive securities
Employee stock option and other award plans	1.4		1.8		1.5			1.8
Weighted average common shares — Diluted	220.8		219.7		220.7			219.6
Basic Earnings Per Common Share Attributable to Air Products
Income from continuing operations		$1.90		$1.40		$2.61			$2.55
Income from discontinued operations	—		8.38		—			8.61
Net Income Attributable to Air Products		$1.90		$9.78		$2.61			$11.16
Diluted Earnings Per Common Share Attributable to Air Products
Income from continuing operations		$1.89		$1.39		$2.59			$2.53
Income from discontinued operations	—		8.31		—			8.53
Net Income Attributable to Air Products		$1.89		$9.70		$2.59			$11.06

Business Segment Information (Tables)

6 Months Ended

Mar. 31, 2018

Segment Reporting Information [Line Items]

Schedule of Segment Reporting Information, by Segment



	Industrial Gases – Americas		Industrial Gases – EMEA		Industrial Gases – Asia		Industrial Gases – Global		Corporate and other			Segment Total
Three Months Ended 31 March 2018
Sales		$913.2		$561.6		$557.6		$101.7		$21.6			$2,155.7
Operating income (loss)	222.3		116.7		148.7		12.1		(44.4		)	455.4
Depreciation and amortization	122.3		50.7		62.6		1.9		2.5			240.0
Equity affiliates' income	16.9		11.1		15.4		.3		—			43.7
Three Months Ended 31 March 2017
Sales		$890.1		$414.2		$435.9		$216.5		$23.4			$1,980.1
Operating income (loss)	223.2		88.6		112.3		22.7		(40.9		)	405.9
Depreciation and amortization	116.0		41.6		49.3		1.7		3.2			211.8
Equity affiliates' income	13.0		8.3		12.9		—		—			34.2




	Industrial Gases – Americas		Industrial Gases – EMEA		Industrial Gases – Asia		Industrial Gases – Global		Corporate and other			Segment Total
Six Months Ended 31 March 2018
Sales		$1,823.0		$1,077.5		$1,201.2		$234.7		$35.9			$4,372.3
Operating income (loss)	439.5		221.2		324.2		21.6		(90.4		)	916.1
Depreciation and amortization	240.1		99.8		119.4		3.5		5.1			467.9
Equity affiliates' income	35.5		24.2		29.6		.7		—			90.0
Six Months Ended 31 March 2017
Sales		$1,754.0		$813.9		$874.2		$364.4		$56.1			$3,862.6
Operating income (loss)	446.5		178.6		230.7		30.9		(70.0		)	816.7
Depreciation and amortization	227.8		83.8		96.0		3.7		6.6			417.9
Equity affiliates' income	27.7		17.8		26.4		.3		—			72.2
Total Assets
31 March 2018		$5,915.0		$3,475.5		$4,779.1		$252.5		$4,089.0			$18,511.1
30 September 2017	5,840.8		3,276.1		4,412.1		279.6		4,648.4			18,457.0

Reconciliation of Segments to Consolidated Operating Income

Below is a reconciliation of segment total operating income to consolidated operating income:



	Three Months Ended					Six Months Ended
	31 March					31 March
Operating Income	2018		2017			2018		2017
Segment total		$455.4		$405.9			$916.1		$816.7
Business separation costs	—		—			—		(32.5		)
Cost reduction and asset actions	—		(10.3		)	—		(60.3		)
Consolidated Total		$455.4		$395.6			$916.1		$723.9

Reconciliation of Segments to Consolidated Equity Affiliates' Income (Loss)

Below is a reconciliation of segment total equity affiliates' income to consolidated equity affiliates' income:



	Three Months Ended				Six Months Ended
	31 March				31 March
Equity Affiliates' Income	2018		2017		2018			2017
Segment total		$43.7		$34.2		$90.0			$72.2
Tax reform repatriation - equity method investment	—		—		(32.5		)	—
Consolidated Total		$43.7		$34.2		$57.5			$72.2

Reconciliation of Segments to Consolidated Total Assets

Below is a reconciliation of segment total assets to consolidated total assets:



	31 March		30 September
Total Assets	2018		2017
Segment total		$18,511.1		$18,457.0
Discontinued operations	—		10.2
Consolidated Total		$18,511.1		$18,467.2

Discontinued Operations (Narrative) (Details) - USD ($)
$ / shares in Units, $ in Millions

3 Months Ended

6 Months Ended

Jan. 03, 2017

Mar. 31, 2018

Mar. 31, 2017

Dec. 31, 2016

Mar. 31, 2018

Mar. 31, 2017

Sep. 30, 2017

Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]

Liability associated with EFW

$ 68.0

Current assets of discontinued operations

0.0

$ 10.2

Current liabilities of discontinued operations

0.0

15.7

Income (Loss) From Discontinued Operations, net of tax

0.0

$ 1,825.6

(1.0)

$ 1,873.8

Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]

Gain (Loss) on sale (disposal), after-tax

1,832.5

1,785.4

Current liabilities of discontinued operations

15.7

Assets of discontinued operations

0.0

Liabilities of discontinued operations

0.0

Income (Loss) From Discontinued Operations, net of tax

$ 0.0

1,825.6

$ (1.0)

1,873.8

Performance Materials Division (PMD) | Discontinued Operations, Held-for-sale or Disposed of by Sale

Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]

Proceeds from sale

$ 3,800.0

Gain on sale, before-tax

2,870.0

Gain (Loss) on sale (disposal), after-tax

$ 1,833.0

1,832.5

Gain on sale, after-tax, per share

$ 8.34

Income (Loss) From Discontinued Operations, net of tax

1,828.1

1,928.8

Energy-from-Waste (EfW) | Discontinued Operations, Held-for-sale or Disposed of by Sale

Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]

Gain (Loss) on sale (disposal), after-tax

^[1]

0.0

(47.1)

Loss on disposal, before-tax

$ 59.3

Loss on disposal, after tax

$ 47.1

Current assets of discontinued operations

$ 10.2

Income (Loss) From Discontinued Operations, net of tax

^[1]

$ (2.5)

$ (55.0)

[1]	The loss from operations of discontinued operations for EfW primarily relates to land lease obligations, administrative costs, and costs incurred for project exit activities.

Discontinued Operations (Schedule of Operating Results) (Details) - USD ($)
$ in Millions

3 Months Ended

6 Months Ended

Jan. 03, 2017

Mar. 31, 2018

Mar. 31, 2017

Dec. 31, 2016

Mar. 31, 2018

Mar. 31, 2017

Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]

Income (Loss) from Discontinued Operations, net of tax

$ 0.0

$ 1,825.6

$ (1.0)

$ 1,873.8

Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]

Sales

254.8

Selling and administrative

6.3

191.9

2.1

22.7

Research and development

5.1

Other income (expense), net

0.3

0.2

Operating Income (Loss)

35.3

Equity affiliates’ income

0.3

Income (Loss) Before Taxes

(8.1)

35.6

Income tax benefit

(1.2)

(52.8)

^[1]

Income (Loss) From Operations of Discontinued Operations, net of tax

(6.9)

88.4

Gain (Loss) on Disposal, net of tax

1,832.5

1,785.4

Income (Loss) from Discontinued Operations, net of tax

$ 0.0

1,825.6

$ (1.0)

1,873.8

Performance Materials Division (PMD) | Discontinued Operations, Held-for-sale or Disposed of by Sale

Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]

Sales

254.8

Selling and administrative

3.3

182.3

2.1

22.5

Research and development

5.1

Other income (expense), net

0.7

0.3

Operating Income (Loss)

45.2

Equity affiliates’ income

0.3

Income (Loss) Before Taxes

(4.7)

45.5

Income tax benefit

(0.3)

(50.8)

^[1]

Income (Loss) From Operations of Discontinued Operations, net of tax

(4.4)

96.3

Gain (Loss) on Disposal, net of tax

$ 1,833.0

1,832.5

Income (Loss) from Discontinued Operations, net of tax

1,828.1

1,928.8

Valuation allowance adjustment effect on income tax provision

$ 66.0

Energy-from-Waste (EfW) | Discontinued Operations, Held-for-sale or Disposed of by Sale

Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]

Sales

^[2]

0.0

Selling and administrative

^[2]

3.0

9.6

^[2]

0.0

0.2

Research and development

^[2]

0.0

Other income (expense), net

^[2]

(0.4)

(0.1)

Operating Income (Loss)

^[2]

(9.9)

Equity affiliates’ income

^[2]

0.0

Income (Loss) Before Taxes

^[2]

(3.4)

(9.9)

Income tax benefit

^[2]

(0.9)

(2.0)

Income (Loss) From Operations of Discontinued Operations, net of tax

^[2]

(2.5)

(7.9)

Gain (Loss) on Disposal, net of tax

^[2]

0.0

(47.1)

Income (Loss) from Discontinued Operations, net of tax

^[2]

$ (2.5)

$ (55.0)

[1]	As a result of the expected gain on the sale of PMD, we released valuation allowances related to capital loss and net operating loss carryforwards during the first quarter of 2017 that favorably impacted our income tax provision within discontinued operations by approximately $66.
[2]	The loss from operations of discontinued operations for EfW primarily relates to land lease obligations, administrative costs, and costs incurred for project exit activities.

Materials Technologies Separation (Narrative) (Details) $ in Millions		3 Months Ended		6 Months Ended
	Oct. 01, 2016	Mar. 31, 2018 USD ($)	Mar. 31, 2017 USD ($)	Mar. 31, 2018 USD ($)	Mar. 31, 2017 USD ($)	Sep. 30, 2017 USD ($)
Restructuring Cost and Reserve [Line Items]
Income (loss) from discontinued operations, net of tax		$ 0.0	$ 1,825.6	$ (1.0)	$ 1,873.8
Business separation costs, legal and advisory fees, before tax		0.0	0.0	0.0	32.5
Materials Technologies
Restructuring Cost and Reserve [Line Items]
Net business separation costs			0.0	0.0	30.2
Materials Technologies \| Business separation costs
Restructuring Cost and Reserve [Line Items]
Business separation costs, legal and advisory fees, before tax					32.5
Materials Technologies \| Other non-operating income (expense), net
Restructuring Cost and Reserve [Line Items]
Pension settlement benefit					2.3
Discontinued Operations, Disposed of by Means Other than Sale, Spinoff \| Electronic Materials Division (EMD)
Restructuring Cost and Reserve [Line Items]
Distribution ratio of common stock in spin-off	0.5
Discontinued Operations \| Electronic Materials Division (EMD)
Restructuring Cost and Reserve [Line Items]
Income (loss) from discontinued operations, net of tax		0.0	$ 0.0	0.0	$ 0.0
Assets of discontinued operations		0.0		0.0		$ 0.0
Liabilities of discontinued operations		$ 0.0		$ 0.0		$ 0.0

Cost Reduction and Asset Actions (Narrative) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended		12 Months Ended
	Mar. 31, 2018	Mar. 31, 2017	Mar. 31, 2018	Mar. 31, 2017	Sep. 30, 2017
Restructuring and Related Cost [Abstract]
Cost reduction and asset actions	$ 0.0	$ 10.3	$ 0.0	$ 60.3	$ 151.4
Cost Reduction Actions
Restructuring and Related Cost [Abstract]
Cost reduction and asset actions					154.8
Cost Reduction Actions \| Industrial Gases - Americas
Restructuring and Related Cost [Abstract]
Cost reduction and asset actions					39.3
Cost Reduction Actions \| Industrial Gases - EMEA
Restructuring and Related Cost [Abstract]
Cost reduction and asset actions					77.9
Cost Reduction Actions \| Industrial Gases - Asia
Restructuring and Related Cost [Abstract]
Cost reduction and asset actions					0.9
Cost Reduction Actions \| Industrial Gases - Global
Restructuring and Related Cost [Abstract]
Cost reduction and asset actions					2.5
Cost Reduction Actions \| Corporate and other
Restructuring and Related Cost [Abstract]
Cost reduction and asset actions					34.2
Cost Reduction Actions \| Severance And Other Benefits
Restructuring and Related Cost [Abstract]
Cost reduction and asset actions		$ 10.3		18.0	66.3
Cost Reduction Actions \| Asset Actions/Other
Restructuring and Related Cost [Abstract]
Cost reduction and asset actions				$ 45.7	88.5
Business Realignment and Reorganization
Restructuring and Related Cost [Abstract]
Favorable restructuring reserve settlement					$ 3.4

Cost Reduction and Asset Actions (Carrying Amount of Accrual) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended		12 Months Ended
	Mar. 31, 2018	Mar. 31, 2017	Mar. 31, 2018	Mar. 31, 2017	Sep. 30, 2017	Sep. 30, 2016
Restructuring Cost and Reserve [Line Items]
Cost reduction and asset actions	$ 0.0	$ 10.3	$ 0.0	$ 60.3	$ 151.4
Cost Reduction Actions
Restructuring Cost and Reserve [Line Items]
Cost reduction and asset actions					154.8
Noncash expenses					(84.2)
Amount reflected in pension liability			(0.4)		(2.0)
Amount reflected in other noncurrent liabilities					(2.2)
Cash expenditures			(24.1)		(36.9)
Currency translation adjustment			0.7		(0.3)
Accrued balance	17.7		17.7		41.5	$ 12.3
Cost Reduction Actions \| Severance And Other Benefits
Restructuring Cost and Reserve [Line Items]
Cost reduction and asset actions		$ 10.3		18.0	66.3
Noncash expenses					0.0
Amount reflected in pension liability			(0.4)		(2.0)
Amount reflected in other noncurrent liabilities					0.0
Cash expenditures			(23.9)		(35.7)
Currency translation adjustment			0.7		(0.3)
Accrued balance	17.0		17.0		40.6	12.3
Cost Reduction Actions \| Asset Actions/Other
Restructuring Cost and Reserve [Line Items]
Cost reduction and asset actions				$ 45.7	88.5
Noncash expenses					(84.2)
Amount reflected in pension liability			0.0		0.0
Amount reflected in other noncurrent liabilities					(2.2)
Cash expenditures			(0.2)		(1.2)
Currency translation adjustment			0.0		0.0
Accrued balance	$ 0.7		$ 0.7		$ 0.9	$ 0.0

Business Combinations (Narrative) (Details) $ in Millions	6 Months Ended
Business Combinations (Narrative) (Details) $ in Millions	Mar. 31, 2018 USD ($)
Business Acquisition [Line Items]
Business combinations, goodwill acquired during period	$ 62.9
2018 Acquisitions
Business Acquisition [Line Items]
Number of acquisitions completed	5
Aggregate purchase price, net of cash acquired	$ 281.0
Business combinations, recognized property, plant, and equipment	168.9
Business combinations, goodwill acquired during period	62.9
Business combinations, tax deductible goodwill	3.0
Business combinations, recognized identifiable intangible assets	$ 65.3
Acquired finite-lived intangible assets, weighted-average useful life	12 years

Business Combinations - Subsequent Event (Details) $ in Millions, ¥ in Billions			3 Months Ended
	Apr. 26, 2018 USD ($)	Apr. 26, 2018 CNY (¥)	Sep. 30, 2018 USD ($)	Sep. 30, 2018 CNY (¥)
Lu'An Asset Acquisition \| Subsequent Event
Subsequent Event [Line Items]
Payments for business combination	$ 270	¥ 1.7
Lu'An Asset Acquisition \| Forecast
Subsequent Event [Line Items]
Payments for business combination			$ 230	¥ 1.5
Air Products Lu'an (Changzhi) Co Ltd \| Joint Venture \| Subsequent Event
Subsequent Event [Line Items]
Ownership interest by Air Products (percent)	60.00%
Ownership interest by noncontrolling owners (percent)	40.00%
Contribution of equipment to joint venture	$ 300
Carrying value of plant and equipment	$ 1,300

Inventories (Schedule of Inventory) (Details) - USD ($) $ in Millions	Mar. 31, 2018	Sep. 30, 2017
Inventory Disclosure [Abstract]
Finished goods	$ 134.3	$ 120.0
Work in process	16.1	15.7
Raw materials, supplies and other	213.6	223.0
Total FIFO cost	364.0	358.7
Less: Excess of FIFO cost over LIFO cost	(24.1)	(23.3)
Inventories	$ 339.9	$ 335.4

Goodwill (Schedule of Goodwill by Segment) (Details) $ in Millions	6 Months Ended
	Mar. 31, 2018 USD ($)
Goodwill [Roll Forward]
Goodwill, net, beginning balance	$ 721.5
Acquisitions	62.9
Currency translation	30.6
Goodwill, net, ending balance	815.0
Industrial Gases - Americas
Goodwill [Roll Forward]
Goodwill, net, beginning balance	163.7
Acquisitions	0.0
Currency translation	3.5
Goodwill, net, ending balance	167.2
Industrial Gases - EMEA
Goodwill [Roll Forward]
Goodwill, net, beginning balance	402.4
Acquisitions	27.7
Currency translation	22.0
Goodwill, net, ending balance	452.1
Industrial Gases - Asia
Goodwill [Roll Forward]
Goodwill, net, beginning balance	135.2
Acquisitions	35.2
Currency translation	5.0
Goodwill, net, ending balance	175.4
Industrial Gases - Global
Goodwill [Roll Forward]
Goodwill, net, beginning balance	20.2
Acquisitions	0.0
Currency translation	0.1
Goodwill, net, ending balance	$ 20.3

Goodwill (Schedule of Accumulated Impairment Losses) (Details) - USD ($) $ in Millions	Mar. 31, 2018	Sep. 30, 2017
Goodwill and Intangible Assets Disclosure [Abstract]
Goodwill, gross	$ 1,257.0	$ 1,138.7
Goodwill, accumulated impairment losses	(442.0)	(417.2)
Goodwill, net	$ 815.0	$ 721.5

Goodwill (Narrative) (Details) - USD ($) $ in Millions	Mar. 31, 2018	Sep. 30, 2017
Goodwill [Line Items]
Goodwill, accumulated impairment losses	$ 442.0	$ 417.2
Industrial Gases - Americas
Goodwill [Line Items]
Goodwill, accumulated impairment losses	$ 442.0

Financial Instruments (Narrative) (Details) € in Millions	6 Months Ended		12 Months Ended
Financial Instruments (Narrative) (Details) € in Millions	Mar. 31, 2018 USD ($)	Mar. 31, 2018 EUR (€)	Sep. 30, 2017 USD ($)	Sep. 30, 2017 EUR (€)
Derivative [Line Items]
Net liability position of derivatives with credit risk-related contingent features	$ 116,900,000		$ 34,600,000
Collateral posted on liability positions with credit risk-related contingent features	0
Collateral amount that counterparties would be required to post	$ 70,900,000		138,500,000
Forward Exchange Contracts \| Cash Flow Hedges
Derivative [Line Items]
Maximum remaining maturity of foreign currency derivatives	2 years	2 years
Foreign Currency Debt \| Euro Denominated
Derivative [Line Items]
Notional amount included in designated foreign currency denominated debt	$ 1,127,100,000	€ 914.6	$ 1,077,700,000	€ 912.2

Financial Instruments (Schedule of Outstanding Currency Price Risk Management Instruments) (Details) - Forward Exchange Contracts - USD ($) $ in Millions	6 Months Ended	12 Months Ended
	Mar. 31, 2018	Sep. 30, 2017
Derivative [Line Items]
US$ Notional	$ 4,313.3	$ 4,099.5
Years Average Maturity	11 months	10 months
Designated as Hedging Instrument \| Cash Flow Hedges
Derivative [Line Items]
US$ Notional	$ 2,953.8	$ 3,150.2
Years Average Maturity	5 months	5 months
Designated as Hedging Instrument \| Net Investment Hedges
Derivative [Line Items]
US$ Notional	$ 369.5	$ 675.5
Years Average Maturity	2 years 6 months	3 years
Not Designated as Hedging Instrument
Derivative [Line Items]
US$ Notional	$ 990.0	$ 273.8
Years Average Maturity	1 year 8 months	1 month

Financial Instruments (Schedule of Interest Rate Swaps and Cross Currency Interest Rate Swaps) (Details) - USD ($) $ in Millions	6 Months Ended	12 Months Ended
	Mar. 31, 2018	Sep. 30, 2017
Interest Rate Swaps Contracts \| Designated as Hedging Instrument \| Fair Value Hedges
Derivative [Line Items]
US$ Notional	$ 400.0	$ 600.0
Average Pay %	LIBOR	LIBOR
Average Receive %	2.53%	2.28%
Years Average Maturity	1 year 4 months 24 days	1 year 3 months 18 days
Cross Currency Interest Rate Swaps \| Designated as Hedging Instrument \| Net Investment Hedges
Derivative [Line Items]
US$ Notional	$ 688.7	$ 539.7
Average Pay %	3.73%	3.27%
Average Receive %	2.76%	2.59%
Years Average Maturity	2 years 3 months 18 days	1 year 10 months 24 days
Cross Currency Interest Rate Swaps \| Designated as Hedging Instrument \| Cash Flow Hedges
Derivative [Line Items]
US$ Notional	$ 1,014.6	$ 1,095.7
Average Pay %	5.01%	4.96%
Average Receive %	2.75%	2.78%
Years Average Maturity	2 years 4 months 24 days	2 years 4 months 24 days
Cross Currency Interest Rate Swaps \| Not Designated as Hedging Instrument
Derivative [Line Items]
US$ Notional	$ 39.5	$ 41.6
Average Pay %	3.16%	3.28%
Average Receive %	2.88%	2.32%
Years Average Maturity	1 year 6 months	1 year 8 months 12 days

Financial Instruments (Fair Value of Derivative Instruments) (Details) - USD ($) $ in Millions	Mar. 31, 2018	Sep. 30, 2017
Derivative [Line Items]
Total Derivatives, Assets	$ 157.6	$ 227.8
Total Derivatives, Liabilities	151.6	131.9
Designated as Hedging Instrument
Derivative [Line Items]
Total Derivatives, Assets	139.8	222.5
Total Derivatives, Liabilities	128.8	128.7
Designated as Hedging Instrument \| Other Receivables \| Forward Exchange Contracts
Derivative [Line Items]
Total Derivatives, Assets	81.7	81.7
Designated as Hedging Instrument \| Other Receivables \| Interest Rate Management Contract
Derivative [Line Items]
Total Derivatives, Assets	5.5	11.1
Designated as Hedging Instrument \| Other Noncurrent Assets \| Forward Exchange Contracts
Derivative [Line Items]
Total Derivatives, Assets	9.1	27.1
Designated as Hedging Instrument \| Other Noncurrent Assets \| Interest Rate Management Contract
Derivative [Line Items]
Total Derivatives, Assets	43.5	102.6
Designated as Hedging Instrument \| Accrued Liabilities \| Forward Exchange Contracts
Derivative [Line Items]
Total Derivatives, Liabilities	31.6	82.0
Designated as Hedging Instrument \| Accrued Liabilities \| Interest Rate Management Contract
Derivative [Line Items]
Total Derivatives, Liabilities	19.4	10.7
Designated as Hedging Instrument \| Other Noncurrent Liabilities \| Forward Exchange Contracts
Derivative [Line Items]
Total Derivatives, Liabilities	19.7	13.8
Designated as Hedging Instrument \| Other Noncurrent Liabilities \| Interest Rate Management Contract
Derivative [Line Items]
Total Derivatives, Liabilities	58.1	22.2
Not Designated as Hedging Instrument
Derivative [Line Items]
Total Derivatives, Assets	17.8	5.3
Total Derivatives, Liabilities	22.8	3.2
Not Designated as Hedging Instrument \| Other Receivables \| Forward Exchange Contracts
Derivative [Line Items]
Total Derivatives, Assets	4.4	1.1
Not Designated as Hedging Instrument \| Other Receivables \| Interest Rate Management Contract
Derivative [Line Items]
Total Derivatives, Assets	0.0	0.0
Not Designated as Hedging Instrument \| Other Noncurrent Assets \| Forward Exchange Contracts
Derivative [Line Items]
Total Derivatives, Assets	9.5	0.0
Not Designated as Hedging Instrument \| Other Noncurrent Assets \| Interest Rate Management Contract
Derivative [Line Items]
Total Derivatives, Assets	3.9	4.2
Not Designated as Hedging Instrument \| Accrued Liabilities \| Forward Exchange Contracts
Derivative [Line Items]
Total Derivatives, Liabilities	5.4	2.2
Not Designated as Hedging Instrument \| Accrued Liabilities \| Interest Rate Management Contract
Derivative [Line Items]
Total Derivatives, Liabilities	0.4	1.0
Not Designated as Hedging Instrument \| Other Noncurrent Liabilities \| Forward Exchange Contracts
Derivative [Line Items]
Total Derivatives, Liabilities	17.0	0.0
Not Designated as Hedging Instrument \| Other Noncurrent Liabilities \| Interest Rate Management Contract
Derivative [Line Items]
Total Derivatives, Liabilities	$ 0.0	$ 0.0

Financial Instruments (Schedule of Gain/Loss Related to Derivative Instruments) (Details) - USD ($)
$ in Millions

3 Months Ended

6 Months Ended

Mar. 31, 2018

Mar. 31, 2017

Mar. 31, 2018

Mar. 31, 2017

Designated as Hedging Instrument | Cash Flow Hedges

Net gain (loss) recognized in OCI (effective portion)

$ 17.8

$ (15.4)

$ 8.3

$ (25.2)

Net (gain) loss reclassified from OCI to sales/cost of sales (effective portion)

4.0

1.2

5.0

5.8

Net (gain) loss reclassified from OCI to other income (expense), net (effective portion)

(13.5)

5.0

(14.7)

26.3

Net (gain) loss reclassified from OCI to interest expense (effective portion)

2.3

(0.9)

3.5

(1.0)

Net (gain) loss reclassified from OCI to other income (expense), net (ineffective portion)

(0.3)

0.5

(0.5)

0.3

Designated as Hedging Instrument | Fair Value Hedges

Net gain (loss) recognized in interest expense

^[1]

(3.6)

(2.8)

(6.8)

(11.9)

Designated as Hedging Instrument | Net Investment Hedges

Not Designated as Hedging Instrument

(60.7)

(15.1)

(96.7)

67.7

Net gain (loss) recognized in other income (expense), net

^[2]

(0.6)

(3.1)

(3.4)

(0.2)

Forward Exchange Contracts | Designated as Hedging Instrument | Cash Flow Hedges

Net gain (loss) recognized in OCI (effective portion)

31.9

11.1

39.4

(48.3)

Net (gain) loss reclassified from OCI to sales/cost of sales (effective portion)

4.0

1.2

5.0

5.8

Net (gain) loss reclassified from OCI to other income (expense), net (effective portion)

(29.3)

(10.8)

(46.9)

38.7

Net (gain) loss reclassified from OCI to interest expense (effective portion)

1.6

(1.6)

2.2

(2.4)

Net (gain) loss reclassified from OCI to other income (expense), net (ineffective portion)

(0.3)

0.5

(0.5)

0.3

Forward Exchange Contracts | Designated as Hedging Instrument | Net Investment Hedges

Forward Exchange Contracts | Not Designated as Hedging Instrument

(15.2)

(0.8)

(22.7)

27.1

Net gain (loss) recognized in other income (expense), net

^[2]

1.6

(2.5)

0.1

(0.4)

Foreign Currency Debt | Designated as Hedging Instrument | Net Investment Hedges

Other Contracts | Designated as Hedging Instrument | Cash Flow Hedges

(22.2)

(7.8)

(39.5)

34.0

Net gain (loss) recognized in OCI (effective portion)

^[3]

(14.1)

(26.5)

(31.1)

23.1

Net (gain) loss reclassified from OCI to sales/cost of sales (effective portion)

^[3]

0.0

Net (gain) loss reclassified from OCI to other income (expense), net (effective portion)

^[3]

15.8

32.2

(12.4)

Net (gain) loss reclassified from OCI to interest expense (effective portion)

^[3]

0.7

1.3

1.4

Net (gain) loss reclassified from OCI to other income (expense), net (ineffective portion)

^[3]

0.0

Other Contracts | Designated as Hedging Instrument | Fair Value Hedges

Net gain (loss) recognized in interest expense

^[1],[3]

(3.6)

(2.8)

(6.8)

(11.9)

Other Contracts | Designated as Hedging Instrument | Net Investment Hedges

Other Contracts | Not Designated as Hedging Instrument

^[3]

(23.3)

(6.5)

(34.5)

6.6

Net gain (loss) recognized in other income (expense), net

^[2],[3]

$ (2.2)

$ (0.6)

$ (3.5)

$ 0.2

[1]	The impact of fair value hedges noted above was largely offset by recognized gains and losses resulting from the impact of changes in related interest rates on outstanding debt.
[2]	The impact of the non-designated hedges noted above was largely offset by recognized gains and losses resulting from the impact of changes in exchange rates on assets and liabilities denominated in non-functional currencies.
[3]	Other includes the impact on other comprehensive income (OCI) and earnings primarily related to interest rate and cross currency interest rate swaps.

Fair Value Measurements (Schedule of the Carrying Values and Fair Values of Financial Instruments) (Details) - USD ($) $ in Millions	Mar. 31, 2018	Sep. 30, 2017
Carrying Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt, including current portion, carrying value	$ 3,454.0	$ 3,818.8
Fair Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt, including current portion fair value	3,459.5	3,928.2
Forward Exchange Contracts \| Carrying Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative assets	104.7	109.9
Derivative liabilities	73.7	98.0
Forward Exchange Contracts \| Fair Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative assets	104.7	109.9
Derivative liabilities	73.7	98.0
Interest Rate Management Contract \| Carrying Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative assets	52.9	117.9
Derivative liabilities	77.9	33.9
Interest Rate Management Contract \| Fair Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative assets	52.9	117.9
Derivative liabilities	$ 77.9	$ 33.9

Fair Value Measurements (Schedule of Recurring Fair Value Measurements) (Details) - Fair Value, Measurements, Recurring - USD ($) $ in Millions	Mar. 31, 2018	Sep. 30, 2017
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total Assets at Fair Value	$ 157.6	$ 227.8
Total Liabilities at Fair Value	151.6	131.9
Level 1
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total Assets at Fair Value	0.0	0.0
Total Liabilities at Fair Value	0.0	0.0
Level 2
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total Assets at Fair Value	157.6	227.8
Total Liabilities at Fair Value	151.6	131.9
Level 3
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total Assets at Fair Value	0.0	0.0
Total Liabilities at Fair Value	0.0	0.0
Forward Exchange Contracts
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative assets	104.7	109.9
Derivative liabilities	73.7	98.0
Forward Exchange Contracts \| Level 1
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative assets	0.0	0.0
Derivative liabilities	0.0	0.0
Forward Exchange Contracts \| Level 2
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative assets	104.7	109.9
Derivative liabilities	73.7	98.0
Forward Exchange Contracts \| Level 3
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative assets	0.0	0.0
Derivative liabilities	0.0	0.0
Interest Rate Management Contract
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative assets	52.9	117.9
Derivative liabilities	77.9	33.9
Interest Rate Management Contract \| Level 1
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative assets	0.0	0.0
Derivative liabilities	0.0	0.0
Interest Rate Management Contract \| Level 2
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative assets	52.9	117.9
Derivative liabilities	77.9	33.9
Interest Rate Management Contract \| Level 3
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative assets	0.0	0.0
Derivative liabilities	$ 0.0	$ 0.0

Retirement Benefits (Narrative) (Details) - Defined Benefit Pension Plan - USD ($) $ in Millions	6 Months Ended		12 Months Ended
	Mar. 31, 2018	Mar. 31, 2017	Sep. 30, 2017
Defined Benefit Plan Disclosure [Line Items]
Company contributions	$ 35.9	$ 40.8	$ 64.1
Minimum
Defined Benefit Plan Disclosure [Line Items]
Total expected contributions for current fiscal year	50.0
Maximum
Defined Benefit Plan Disclosure [Line Items]
Total expected contributions for current fiscal year	$ 70.0
Discontinued Operations
Defined Benefit Plan Disclosure [Line Items]
Service cost		$ 1.3

Retirement Benefits (Schedule of Net Periodic Benefit Cost) (Details) - Defined Benefit Pension Plan - USD ($)
$ in Millions

3 Months Ended

6 Months Ended

Mar. 31, 2018

Mar. 31, 2017

Mar. 31, 2018

Mar. 31, 2017

Service cost

$ 1.3

U.S.

Expected return on plan assets

Service cost

$ 6.4

$ 6.9

$ 12.8

^[1]

15.2

^[1]

Interest cost

26.8

27.6

53.5

52.5

(50.4)

(51.7)

(100.8)

(104.4)

Prior service cost amortization

0.4

0.6

0.8

1.2

Actuarial loss amortization

22.2

20.9

43.9

47.0

Settlements

1.5

4.1

3.3

4.1

Curtailment

0.0

0.1

0.0

4.3

Special termination benefits

0.4

(0.1)

0.4

1.0

Other

0.0

U.S. | Discontinued Operations

7.3

8.4

13.9

20.9

U.S. | Continuing Operations

0.0

0.1

0.0

0.7

7.3

8.3

13.9

20.2

International

Expected return on plan assets

Service cost

6.6

6.3

12.9

^[1]

13.0

^[1]

Interest cost

9.6

7.9

18.8

15.5

(21.1)

(18.3)

(41.3)

(36.8)

Prior service cost amortization

0.0

(0.1)

0.0

(0.1)

Actuarial loss amortization

10.3

13.2

20.3

27.1

Settlements

0.0

4.0

0.0

1.7

Curtailment

0.0

1.8

0.0

(1.3)

Special termination benefits

0.0

0.1

0.0

0.5

Other

0.1

(2.2)

0.6

0.5

International | Discontinued Operations

5.5

12.7

11.3

20.1

International | Continuing Operations

0.0

3.4

0.0

4.1

Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]

$ 5.5

$ 9.3

$ 11.3

$ 16.0

[1]	Includes total service costs from discontinued operations of $1.3 for the six months ended 31 March 2017.

Commitments and Contingencies (Litigation and Environmental - Narrative) (Details) R$ in Millions	1 Months Ended	6 Months Ended
	Sep. 30, 2010 BRL (R$)	Mar. 31, 2018 USD ($) site	Mar. 31, 2018 BRL (R$) site	Sep. 30, 2017 USD ($)
Alleged Anticompete Litigation
Loss Contingencies [Line Items]
Civil fines imposed	R$ 179.2	$ 54,000,000
Provision for litigation		0
Maximum of loss contingency range subject to interest		$ 54,000,000	R$ 179.2
Environmental
Loss Contingencies [Line Items]
Approximate number of sites on which settlement has not been reached \| site		33	33
Accrual for environmental loss contingencies		$ 81,000,000.0		$ 83,600,000
Accrual for environmental loss contingencies, maximum payout period		30 years
Environmental \| Minimum
Loss Contingencies [Line Items]
Estimate of possible exposure from environmental loss contingencies		$ 80,000,000
Environmental \| Maximum
Loss Contingencies [Line Items]
Estimate of possible exposure from environmental loss contingencies		$ 95,000,000

Commitments and Contingencies (Pace, Piedmont, Pasadena Narrative) (Details) - USD ($)	6 Months Ended	12 Months Ended
	Mar. 31, 2018	Sep. 30, 2012	Sep. 30, 2008	Sep. 30, 2006
Pace, Florida
Loss Contingencies [Line Items]
Accrual for environmental loss contingencies	$ 28,200,000			$ 42,000,000
Change in estimated exposure	0
Pace, Florida \| Discontinued Operations
Loss Contingencies [Line Items]
Pretax environmental expense				42,000,000
Pace, Florida \| Minimum
Loss Contingencies [Line Items]
Estimate of possible exposure from environmental loss contingencies				42,000,000
Pace, Florida \| Maximum
Loss Contingencies [Line Items]
Estimate of possible exposure from environmental loss contingencies				$ 52,000,000
Piedmont, South Carolina
Loss Contingencies [Line Items]
Accrual for environmental loss contingencies	16,200,000		$ 24,000,000
Piedmont, South Carolina \| Discontinued Operations
Loss Contingencies [Line Items]
Pretax environmental expense			$ 24,000,000
Pasadena, Texas
Loss Contingencies [Line Items]
Accrual for environmental loss contingencies	$ 11,900,000
Total anticipated exposure		$ 13,000,000

Commitments and Contingencies (Unconditional Purchase Obligations) (Details) $ in Millions	Mar. 31, 2018 USD ($)
Helium Purchases [Member]
Unrecorded Unconditional Purchase Obligation [Line Items]
Unconditional purchase obligation	$ 6,500

Share-Based Compensation (Narrative) (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended		6 Months Ended
	Mar. 31, 2018	Mar. 31, 2017	Mar. 31, 2018	Mar. 31, 2017
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares available for future grant	4,610,336		4,610,336
Incremental share-based compensation expense	$ 10.7	$ 9.5	$ 22.5	$ 18.5
Market-Based Deferred Stock Unit
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of units/shares granted			104,874
Performance period			3 years
Weighted average grant date fair value (in dollars per unit/share)			$ 202.50
Time-Based Deferred Stock Unit
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of units/shares granted			138,340
Weighted average grant date fair value (in dollars per unit/share)			$ 162.12

Share-Based Compensation (Compensation Cost Recognized in Income Statement) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Mar. 31, 2018	Mar. 31, 2017	Mar. 31, 2018	Mar. 31, 2017
Employee Service Share-based Compensation, Aggregate Disclosures [Abstract]
Before-tax share-based compensation cost	$ 10.7	$ 9.5	$ 22.5	$ 18.5
Income tax benefit	(2.1)	(3.3)	(5.3)	(6.3)
After-tax share-based compensation cost	$ 8.6	$ 6.2	$ 17.2	$ 12.2

Share-Based Compensation (Market-Based Deferred Stock Unit Valuation Assumptions) (Details) - Market-Based Deferred Stock Unit	6 Months Ended
	Mar. 31, 2018
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected volatility	18.70%
Risk-free interest rate	1.90%
Expected dividend yield	2.60%

Equity (Changes in Equity) (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended		6 Months Ended
	Mar. 31, 2018	Mar. 31, 2017	Mar. 31, 2018	Mar. 31, 2017
Stockholders' Equity [Roll Forward]
Beginning balance	$ 10,321.2	$ 7,261.1	$ 10,185.5	$ 7,213.4
Net income	423.6	2,135.7	585.3	2,442.1
Other comprehensive income (loss)	162.5	223.0	316.2	(15.0)
Dividends on common stock	(241.1)	(206.9)	(449.1)	(394.0)
Dividends to noncontrolling interests	(2.9)	(7.5)	(10.6)	(11.7)
Share-based compensation	10.7	9.5	21.8	18.5
Treasury shares for stock option and award plans	20.2	7.9	40.1	7.6
Spin-off of Versum			0.0	(152.6)
Cumulative change in accounting principle			0.0	8.8
Other equity transactions	(1.0)	(2.6)	4.0	(2.1)
Ending balance	$ 10,693.2	$ 9,420.2	$ 10,693.2	$ 9,420.2
Dividends per share (in dollars per share)	$ 1.10	$ 0.95	$ 2.05	$ 1.81
Air Products Shareholders' Equity
Stockholders' Equity [Roll Forward]
Beginning balance	$ 10,215.3	$ 7,161.5	$ 10,086.2	$ 7,079.6
Net income	416.4	2,130.0	571.0	2,429.8
Other comprehensive income (loss)	160.3	218.0	312.1	(16.9)
Dividends on common stock	(241.1)	(206.9)	(449.1)	(394.0)
Share-based compensation	10.7	9.5	21.8	18.5
Treasury shares for stock option and award plans	20.2	7.9	40.1	7.6
Spin-off of Versum			0.0	(186.5)
Cumulative change in accounting principle			0.0	8.8
Other equity transactions	(1.0)	(2.6)	(1.3)	(2.5)
Ending balance	10,580.8	9,317.4	10,580.8	9,317.4
Non-controlling Interests
Stockholders' Equity [Roll Forward]
Beginning balance	105.9	99.6	99.3	133.8
Net income	7.2	5.7	14.3	12.3
Other comprehensive income (loss)	2.2	5.0	4.1	1.9
Dividends to noncontrolling interests	(2.9)	(7.5)	(10.6)	(11.7)
Spin-off of Versum			0.0	(33.9)
Other equity transactions	0.0	0.0	5.3	0.4
Ending balance	$ 112.4	$ 102.8	$ 112.4	$ 102.8

Accumulated Other Comprehensive Loss (Rollforward) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Mar. 31, 2018	Mar. 31, 2017	Mar. 31, 2018	Mar. 31, 2017
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning balance	$ 10,321.2	$ 7,261.1	$ 10,185.5	$ 7,213.4
Other comprehensive income before reclassifications	143.4		270.3
Amounts reclassified from AOCL	19.1		45.9
Total Other Comprehensive Income	162.5	223.0	316.2	(15.0)
Amount attributable to noncontrolling interests	2.2	5.0	4.1	1.9
Ending balance	10,693.2	$ 9,420.2	10,693.2	$ 9,420.2
Derivatives qualifying as hedges
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning balance	(61.8)		(53.1)
Other comprehensive income before reclassifications	17.8		8.3
Amounts reclassified from AOCL	(7.5)		(6.7)
Total Other Comprehensive Income	10.3		1.6
Amount attributable to noncontrolling interests	(0.1)		(0.1)
Ending balance	(51.4)		(51.4)
Foreign currency translation adjustments
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning balance	(649.5)		(787.1)
Other comprehensive income before reclassifications	125.6		262.0
Amounts reclassified from AOCL	0.0		3.1
Total Other Comprehensive Income	125.6		265.1
Amount attributable to noncontrolling interests	2.3		4.2
Ending balance	(526.2)		(526.2)
Pension and postretirement benefits
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning balance	(984.3)		(1,007.2)
Other comprehensive income before reclassifications	0.0		0.0
Amounts reclassified from AOCL	26.6		49.5
Total Other Comprehensive Income	26.6		49.5
Amount attributable to noncontrolling interests	0.0		0.0
Ending balance	(957.7)		(957.7)
AOCL attributable to Air Products
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning balance	(1,695.6)		(1,847.4)
Ending balance	$ (1,535.3)		$ (1,535.3)

Accumulated Other Comprehensive Loss (Reclassification) (Details) - USD ($)
$ in Millions

3 Months Ended

6 Months Ended

Mar. 31, 2018

Mar. 31, 2017

Mar. 31, 2018

Mar. 31, 2017

Other income/expense, net

$ (15.3)

$ (22.0)

$ (37.4)

$ (46.7)

Interest expense

30.4

30.5

60.2

60.0

Income (loss) from discontinued operations, net of tax

1,506.5

1,403.8

3,078.3

2,720.5

0.0

(1,825.6)

1.0

(1,873.8)

Net Income (Loss) Attributable to Air Products

(416.4)

(2,130.0)

(571.0)

(2,429.8)

Reclassification out of Accumulated Other Comprehensive Income | (Gain) Loss on Cash Flow Hedges, net of tax

Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]

Sales/Cost of sales

4.0

1.2

5.0

5.8

Other income/expense, net

(13.8)

5.5

(15.2)

26.6

Interest expense

2.3

(0.9)

3.5

(1.0)

Net Income (Loss) Attributable to Air Products

(7.5)

5.8

(6.7)

31.4

Reclassification out of Accumulated Other Comprehensive Income | Currency Translation Adjustment

Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]