Stockholders' Equity and Compensation Arrangements Repurchase Program (Details) - Common Class A [Member] - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2016	Apr. 04, 2016	Mar. 31, 2015
Employee Stock Purchase Plan [Line Items]
Stock Repurchase Program, Authorized Amount			$ 500.0
Stock Repurchased During Period, Shares	18,820,000
Stock Repurchased During Period, Value	$ 63.4
Stock Repurchase Program, Remaining Number of Shares Authorized to be Repurchased	$ 93.6
Subsequent Event [Member]
Employee Stock Purchase Plan [Line Items]
Stock Repurchase Program, Authorized Amount		$ 200.0