Income Taxes (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Income Taxes
Effective tax rate (as a percent)	26.90%	26.50%	27.20%	26.70%
Impact to effective tax rate relating to acquisition-related expenses in basis points	0.40%		0.70%	0.20%
Unrecognized tax benefits, anticipated adjustment for changing facts and circumstances, over the next twelve month period	$ 6.6		$ 6.6
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	$ 125.5		$ 125.5