Accumulated Other Comprehensive Loss (Reclassification) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Dec. 31, 2014		Dec. 31, 2013
Reclassification Adjustment Out Of Accumulated Other Comprehensive Income (Loss) [Line Items]
Other income/expense, net	$ (8.3)		$ (20.4)
Interest expense	29.1		33.3
Net Income Attributable to Air Products	(324.6)		(290.2)
Income (Loss) from discontinued operations, net of tax	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	(0.6)		0.2
Other income/expense, net	14.1		(11.9)
Interest expense	0		(0.2)
Net Income Attributable to Air Products	13.5		(11.9)
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	$ 20.9	[1]	$ 20.0	[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.