Income Taxes (Effective Income Tax Rate Reconciliation) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Income Tax Disclosure [Abstract]
Federal statutory rate	$ (16.8)	$ 5.6	$ 38.1
Adjustment to valuation allowances	(0.2)	(6.9)	(20.0)
Impact from foreign branches	(2.5)	(3.7)	(2.6)
State taxes, net of federal benefit	(4.1)	(0.8)	2.6
Foreign rate differential	0.0	(0.8)	(2.9)
Impact from foreign branches	2.6	2.6	7.1
Adjustment of deferred tax liabilities	(1.6)	1.4	(1.7)
Federal rate change	0.0	(0.8)	(28.8)
Domestic production activity deduction	0.0	0.0	(0.9)
Other	(1.8)	1.0	(0.1)
Total income tax benefit	$ (24.4)	$ (2.4)	$ (9.2)