Condensed Consolidated Statements of Comprehensive Income (unaudited) (Parenthetical) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Statement of Comprehensive Income [Abstract]
Tax on (loss) gain on derivative instruments	$ 2.4	$ 0.6	$ (11.9)	$ (6.5)
Tax on reclassification on derivative instruments	(1.9)	(1.3)	(2.3)	4.0
Tax on foreign currency adjustments	(55.3)	0.0	(4.7)	(3.1)
Tax on benefit plans	$ (0.1)	$ (0.2)	$ (0.7)	$ (0.2)