Shareholders' Equity - Stock Repurchase (Details) - October 2015 Stock Repurchase Program [Member] - USD ($) shares in Millions	1 Months Ended	3 Months Ended
	Apr. 29, 2016	Mar. 31, 2016	Dec. 31, 2015	Oct. 31, 2015
Subsequent Event [Line Items]
Stock Repurchase Program, Authorized Amount				$ 500,000,000
Treasury Stock, Shares, Acquired		2.8
Treasury Stock, Value, Acquired, Cost Method		$ 200,000,000	$ 200,000,000
Subsequent Event [Member]
Subsequent Event [Line Items]
Treasury Stock, Shares, Acquired	0.6
Treasury Stock, Value, Acquired, Cost Method	$ 50,000,000
Stock Repurchase Program, Remaining Authorized Repurchase Amount	$ 50,000,000