Income Taxes Income Taxes - Rollforward of Deferred Tax Assets Valuation Allowance (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Valuation Allowance [Line Items]
Deferred Tax Assets, Valuation Allowance, Beginning Balance	$ 141.0	$ 170.0	$ 113.3
Change in assessment	5.6	(22.9)	0.0
Current year operations	(16.8)	(6.1)	56.7
Deferred Tax Assets, Valuation Allowance, Ending Balance	129.8	141.0	170.0
State and Local Jurisdiction [Member]
Valuation Allowance [Line Items]
Deferred Tax Assets, Valuation Allowance, Beginning Balance	57.3	72.4	45.9
Change in assessment	0.0	0.0	0.0
Current year operations	(8.8)	(15.1)	26.5
Deferred Tax Assets, Valuation Allowance, Ending Balance	48.5	57.3	72.4
Foreign Tax Authority [Member]
Valuation Allowance [Line Items]
Deferred Tax Assets, Valuation Allowance, Beginning Balance	83.7	97.6	67.4
Change in assessment	5.6	(22.9)	0.0
Current year operations	(8.0)	9.0	30.2
Deferred Tax Assets, Valuation Allowance, Ending Balance	$ 81.3	$ 83.7	$ 97.6