Income Taxes - Quarterly Disclosure (Details9) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Investments, Owned, Federal Income Tax Note [Line Items]
Income tax (provision) benefit	$ 1.9	$ 4.3	$ 2.0	$ 64.4
Non-deductible goodwill impairment	106.0
Discrete tax benefits (expense)	$ 0.3	(4.1)	$ 7.0	$ (0.5)
Change in income tax valuation allowance		$ 173.1
Effective income tax rate				9.10%