Income Taxes (Narrative) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Income Tax Disclosure [Abstract]
Provision for Income Taxes	$ 122.9	$ 131.7	$ 237.7	$ 245.5
Effective Tax Rate	31.40%	33.40%	30.40%	32.60%