Income Taxes (Details) - USD ($) $ in Millions	6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014
Income Taxes [Abstract]
Effective tax rate	32.80%	32.20%
Income tax benefit, merger expenses	$ 11.0
Effective tax rate, excluding merger expenses		33.50%
Unrecognized tax benefits	62.0
Unrecognized tax benefits that would impact effective tax rate	$ 51.1