Unaudited Quarterly Results Unaudited Quarterly Results 2 (Details) - USD ($) $ in Millions	3 Months Ended					12 Months Ended
	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Quarterly Financial Information Disclosure [Abstract]
Restructuring provision	$ 15.8	$ 11.1	$ 17.6	$ 0.7	$ 27.8	$ 35.8	$ 27.8
Restructuring charge, net of tax	$ 11.5	$ 11.5	$ 14.0	$ 0.4	$ 17.5