Income Taxes (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Income Taxes
Effective tax rate (as a percent)	26.50%	27.10%	27.50%	26.80%
Effective tax rate excluding the net impact of acquisition-related expenses (as a percent)	26.50%	26.50%	26.50%	26.50%
Unrecognized tax benefits, anticipated adjustment for changing facts and circumstances, over the next twelve month period	$ 2.9		$ 2.9
Accrued pension benefit obligations and other long-term liabilities
Income Taxes
Liability for unrecognized tax benefits, which if recognized would impact the effective tax rate	$ 124.6		$ 124.6