Income Taxes - Unrecognized Tax Benefits (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Income Taxes
Undistributed earnings of foreign subsidiaries on which U.S. income taxes are not provided	$ 1,200.0
Unrecognized deferred U.S. income taxes on undistributed earnings of foreign subsidiaries	90.0
Gross unrecognized tax benefits, excluding interest	6.2
Portion of unrecognized tax benefits, excluding interest, which if recognized, would result in a reduction of the effective tax rate	5.3
Reasonably possible reduction in unrecognized tax benefits due to statutes of limitations expiring and favorably settling with taxing authorities	2.1
Reconciliation of beginning and ending amount of unrecognized tax benefits
Gross unrecognized tax benefits at the beginning of the year	33.2	$ 40.0	$ 51.7
Gross decreases - tax positions in prior periods	(4.8)	(1.5)	(6.4)
Gross increases - current period tax positions	0.9	0.4
Gross decreases - current period tax positions			(0.3)
Settlements	(21.3)	(2.7)	(0.6)
Lapse of statutes	(1.8)	(3.0)	(4.4)
Gross unrecognized tax benefits at the end of the year	6.2	33.2	$ 40.0
Accrued interest and penalties related to uncertain tax positions	0.5	4.7
Penalties and interest (benefit) expense relating to unrecognized tax benefits	$ (1.8)	$ 1.4