Accumulated Other Comprehensive Loss (Reclassification) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended				6 Months Ended
	Mar. 31, 2015		Mar. 31, 2014		Mar. 31, 2015		Mar. 31, 2014
Reclassification Adjustment Out Of Accumulated Other Comprehensive Income (Loss) [Line Items]
Other income/expense, net	$ (4.7)		$ (17.0)		$ (13.0)		$ (37.4)
Interest expense	23.4		31.5		52.5		64.8
Net Income Attributable to Air Products	(290.0)		(283.5)		(614.6)		(573.7)
Income (Loss) from discontinued operations, net of tax	0		0		0		3.1
Reclassification Out Of Accumulated Other Comprehensive Income [Member] | (Gain) Loss on Cash Flow Hedges [Member]
Reclassification Adjustment Out Of Accumulated Other Comprehensive Income (Loss) [Line Items]
Sales/Cost of sales	0.9		0.8		0.3		1.0
Other income/expense, net	16.0		(11.1)		30.1		(23.0)
Interest expense	0.7		(0.5)		0.7		(0.7)
Net Income Attributable to Air Products	17.6		(10.8)		31.1		(22.7)
Reclassification Out Of Accumulated Other Comprehensive Income [Member] | Pension and postretirement benefits [Member]
Reclassification Adjustment Out Of Accumulated Other Comprehensive Income (Loss) [Line Items]
Net Income Attributable to Air Products	$ 28.6	[1]	$ 20.6	[1]	$ 49.5	[1]	$ 40.6	[1]

[1] 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 10, Retirement Benefits.