Consolidated Comprehensive Income Statements (Unaudited) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Statement of Comprehensive Income [Abstract]
Net Income	$ 500.2	$ 487.9	$ 1,290.7	$ 1,073.2
Other Comprehensive Income (Loss), net of tax:
Translation adjustments, net of tax	(48.8)	(392.4)	(65.6)	(130.4)
Net gain (loss) on derivatives, net of tax	7.5	27.1	(38.2)	35.4
Pension and postretirement benefits, net of tax			(3.9)	0.0
Reclassification adjustments:
Currency translation adjustment	(2.6)	0.0	(2.6)	3.1
Derivatives, net of tax	(13.1)	(17.7)	20.7	(24.4)
Pension and postretirement benefits, net of tax	14.8	26.0	48.7	75.5
Total Other Comprehensive Loss	(42.2)	(357.0)	(40.9)	(40.8)
Comprehensive Income	458.0	130.9	1,249.8	1,032.4
Net Income Attributable to Noncontrolling Interests	12.2	14.0	33.9	28.3
Other Comprehensive Loss Attributable to Noncontrolling Interests	(5.6)	(14.5)	(1.4)	(10.4)
Comprehensive Income Attributable to Air Products	$ 451.4	$ 131.4	$ 1,217.3	$ 1,014.5