Basis Of Presentation (Details) (USD $) In Millions, except Per Share data, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Increase in Earnings from operations due to net favorable cumulative catch-up adjustments	$ 59	$ 122	$ 164	$ 234
Increase in diluted earnings per share due to net favorable cumulative catch-up adjustments	$ 0.04	$ 0.11	$ 0.15	$ 0.20