Basis Of Presentation (Details) (USD $) In Millions, except Per Share data, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012	Jun. 30, 2011
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Increase in operating earnings due to net favorable cumulative catch-up adjustments	$ 122	$ 100	$ 234	$ 153
Increase in earnings per share due to net favorable cumulative catch-up adjustments	$ 0.11	$ 0.09	$ 0.20	$ 0.14