Income Taxes (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016	Dec. 31, 2016
Effective Income Tax Rate Reconciliation, Percent	13.70%	19.00%	14.50%	18.70%
Unrecognized Tax Benefits	$ 21.3		$ 21.3		$ 20.8
Unrecognized Tax Benefits that Would Impact Effective Tax Rate	18.5		18.5
Unrecognized Tax Benefits, Income Tax Penalties and Interest Expense			9.4
Minimum [Member]
Significant Change in Unrecognized Tax Benefits is Reasonably Possible, Amount of Unrecorded Benefit	1.8		1.8
Maximum [Member]
Significant Change in Unrecognized Tax Benefits is Reasonably Possible, Amount of Unrecorded Benefit	$ 16.1		$ 16.1