Accumulated Other Comprehensive Loss (Rollforward) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Dec. 31, 2013	Dec. 31, 2012
Accumulated Other Comprehensive Income Loss [Line Items]
Beginning Balance	$ (1,020.6)
Net current-period other comprehensive income	52.6	104.5
Ending Balance	(966.9)
Net loss on derivatives qualifying as hedges [Member]
Accumulated Other Comprehensive Income Loss [Line Items]
Beginning Balance	(4.1)
Other comprehensive income before reclassifications	13.1
Amounts reclassified from AOCL	(11.9)
Net current-period other comprehensive income	1.2
Ending Balance	(2.9)
Foreign currency translation adjustments [Member]
Accumulated Other Comprehensive Income Loss [Line Items]
Beginning Balance	(61.5)
Other comprehensive income before reclassifications	32.5
Amounts reclassified from AOCL	0
Net current-period other comprehensive income	32.5
Ending Balance	(29.0)
Pension and postretirement benefits [Member]
Accumulated Other Comprehensive Income Loss [Line Items]
Beginning Balance	(955.0)
Other comprehensive income before reclassifications	0
Amounts reclassified from AOCL	20.0
Net current-period other comprehensive income	20.0
Ending Balance	(935.0)
Air Products [Member]
Accumulated Other Comprehensive Income Loss [Line Items]
Beginning Balance	(1,020.6)
Other comprehensive income before reclassifications	45.6
Amounts reclassified from AOCL	8.1
Net current-period other comprehensive income	53.7	103.4
Ending Balance	$ (966.9)