Employee Benefit Plans Employee Benefit Plans (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
401k
Defined Contribution Plan Disclosure [Line Items]
Minimum Qualifying Age For Employee Benefit Plan	21 years
Expenses related to savings plan	$ 45.2	$ 51.8	$ 49.3
Deferred Compensation Plan
Defined Contribution Plan Disclosure [Line Items]
Deferred compensation liability	$ 128.5	$ 126.9