Consolidated Comprehensive Income Statements - USD ($) $ in Millions	3 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Comprehensive Income (Loss), Net of Tax, Including Portion Attributable to Noncontrolling Interest [Abstract]
Net Income	$ 306.4	$ 372.0
Translation adjustments, net of tax of $32.3 and ($6.7)	(281.2)	(102.9)
Net gain (loss) on derivatives, net of tax of ($10.7) and $4.8	(9.8)	16.0
Reclassification adjustments:
Currency translation adjustment	0.0	2.4
Derivatives, net of tax of $10.6 and ($8.0)	25.6	(19.3)
Pension and postretirement benefits, net of tax of $12.9 and $10.1	27.4	21.1
Total Other Comprehensive Loss	(238.0)	(82.7)
Comprehensive Income	68.4	289.3
Net Income Attributable to Noncontrolling Interests	6.6	8.4
Other Comprehensive Loss Attributable to Noncontrolling Interests	(3.1)	0.0
Comprehensive Income Attributable to Air Products	$ 64.9	$ 280.9