Amount of gain (loss) associated with the sale or write-down of assets.

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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Carrying amount as of the balance sheet date of obligations due all related parties. For classified balance sheets, represents the current portion of such liabilities (due within one year or within the normal operating cycle if longer).

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The parent entity's interest in net assets of the subsidiary, expressed as a percentage.

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The amount for notes payable (written promise to pay), payable to related parties, which are due after one year (or one business cycle).

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Supplemental Information (Narrative) (Details) $ in Millions, ¥ in Billions	3 Months Ended
	Dec. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)	Dec. 31, 2018 CNY (¥)	Sep. 30, 2018 USD ($)	Sep. 30, 2018 CNY (¥)	Apr. 26, 2018 CNY (¥)
Debt Instrument [Line Items]
Facility closure	$ 29.0	$ 0.0
Sales to related parties	85.0	$ 105.0
Long-term debt – related party	360.2			$ 384.3
Liability for expected cash payments to or on behalf of related party	283.3		¥ 1.9	$ 330.0	¥ 2.2	¥ 2.3
Current portion of long-term debt – related party	$ 23.6
Joint Venture \| Air Products Lu'an Changzhi Co Ltd
Debt Instrument [Line Items]
Ownership interest by Air Products (percent)						60.00%
Loans Payable \| Lu'An Loan To Joint Venture
Debt Instrument [Line Items]
Long-term debt – related party \| ¥						¥ 2.6