Stockholders' Equity Stockholders' Equity (Capital Stock Activity) (Details) - shares shares in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Capital Stock Activity [Line Items]
Common Stock, Issued Shares, Beginning Balance	286,300
Common Stock, Issued Shares, Ending Balance	286,300	286,300
Common Stock Issued
Capital Stock Activity [Line Items]
Common Stock, Issued Shares, Beginning Balance	286,318	286,318	286,318
Common Stock, Issued Shares, Ending Balance	286,318	286,318	286,318
Common Stock Held In Employee Benefit Trust
Capital Stock Activity [Line Items]
Common Stock, Issued Shares, Beginning Balance	167	180	196
Net Stock Purchased for (Sold from) Employee Benefit Trust	(10)	(13)	(16)
Common Stock, Issued Shares, Ending Balance	157	167	180
Common Stock Held in Treasury
Capital Stock Activity [Line Items]
Common Stock, Issued Shares, Beginning Balance	54,626	50,318	49,061
Stock Awards	(523)	(547)	(998)
Treasury Stock Purchases	5,253	4,855	2,255
Common Stock, Issued Shares, Ending Balance	59,356	54,626	50,318