Discontinued Operations, Assets Held for Sale and Divestitures Disposal Group, Detail of Gain on Sale - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Mar. 31, 2017	Mar. 31, 2016	Mar. 31, 2017	Mar. 31, 2016	Jan. 06, 2017
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Disposal Group, Including Discontinued Operation, Consideration					$ 305.7
Discontinued Operations, Receivable from Buyer of Discontinued Operation					1.9
Total proceeds					307.6
Transaction expenses					(8.3)
Net proceeds					299.3
Assets and liabilities disposed					$ (189.8)
Discontinued Operation, Gain (Loss) from Disposal of Discontinued Operation, before Income Tax	$ 109.5
Income tax on Gain on Sale	(41.6)
Gain on sale, net of tax	$ 67.9	$ 0.0	$ 67.9	$ 0.0