Income Taxes - Income and Taxes from Cont. Operations (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Income (loss) from continuing operations before income taxes
U.S.	$ (41.6)	$ (28.3)	$ (23.2)
Foreign	223.1	153.3	64.3
Income from continuing operations before tax	181.5	125.0	41.1
Current tax expense (benefit)
U.S. federal	(33.7)	(3.3)	(1.0)
State	0.4	0.5	(0.2)
Foreign	96.8	84.2	60.6
Current tax expense	63.5	81.4	59.4
Deferred tax expense (benefit)
U.S. federal	106.2	0.6	7.7
State	(4.9)	(0.1)	0.0
Foreign	(7.1)	(3.4)	(0.6)
Deferred tax expense (benefit)	94.2	(2.9)	7.1
Provision for income taxes of continuing operations	157.7	78.5	66.5
Comprehensive provision (benefit) for income taxes allocable to
Continuing operations	157.7	78.5	66.5
Discontinued operations	(0.1)	(1.1)	(1.0)
Other comprehensive income (loss)	(1.8)	0.9	(0.7)
Equity	0.0	(0.2)	1.8
Comprehensive provision for income taxes	$ 155.8	$ 78.1	$ 66.6