Accumulated Other Comprehensive Loss (Reclassification) (Details) - USD ($) $ in Millions		3 Months Ended
		Dec. 31, 2015	Dec. 31, 2014
Reclassification Adjustment Out Of Accumulated Other Comprehensive Income [Line Items]
Other (income) expense, net		$ (5.9)	$ (8.3)
Interest expense		22.2	29.1
Net Income Attributable to Air Products		(363.6)	(324.6)
Income (Loss) from discontinued operations, net of tax		0.0	0.0
Reclassification Out Of Accumulated Other Comprehensive Income [Member] | (Gain) Loss on Cash Flow Hedges, net of tax [Member]
Reclassification Adjustment Out Of Accumulated Other Comprehensive Income [Line Items]
Sales/cost of sales		0.9	(0.6)
Other (income) expense, net		(22.4)	14.1
Interest expense		2.2	0.0
Net Income Attributable to Air Products		(19.3)	13.5
Reclassification Out Of Accumulated Other Comprehensive Income [Member] | Currency Translation Adjustment [Member]
Reclassification Adjustment Out Of Accumulated Other Comprehensive Income [Line Items]
Other (income) expense, net	[1]	2.4	0.0
Reclassification Out Of Accumulated Other Comprehensive Income [Member] | Pension and Postretirement Benefits, net of tax [Member]
Reclassification Adjustment Out Of Accumulated Other Comprehensive Income [Line Items]
Net Income Attributable to Air Products	[2]	$ 21.1	$ 20.9

[1] The impact is reflected in Other income (expense), net and relates to the sale of an equity affiliate. Refer to Note 7, Equity Affiliates.

[2] The components include items such as prior service cost amortization, actuarial loss amortization, and settlements and are reflected in net periodic benefit cost. Refer to Note 12, Retirement Benefits.