Basis Of Presentation (Details) (USD $) In Millions, except Per Share data, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Increase in operating earnings due to net favorable cumulative catch-up adjustments	$ 74	$ 25	$ 308	$ 178
Increase in earnings per share due to net favorable cumulative catch-up adjustments	$ 0.07	$ 0.02	$ 0.27	$ 0.16