Stockholders' Equity (Summary Of Shares Repurchased) (Details)	12 Months Ended
	Dec. 31, 2015 USD ($) item shares	Dec. 31, 2014 USD ($) shares	Dec. 31, 2013 USD ($) shares
Equity [Abstract]
Purchase of Treasury Stock | $	$ 250,000,000	$ 375,000,000	$ 500,000,000
Shares Repurchased | shares	5,967,313	6,373,718	7,855,419
Number of open share buyback programs | item	0