Supplemental Quarterly Financial Information (Schedule Of Quarterly Financial Information) (Details) (USD $) In Millions, except Per Share data, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Quarterly Financial Data [Abstract]
Operating revenues	$ 2,624	$ 2,714	$ 3,088	$ 1,971	$ 2,580	$ 1,865	$ 2,561	$ 2,495	$ 10,397	$ 9,501	$ 11,445
Earnings (loss) from continuing operations before income taxes	475	639	997	(1,962)	(501)	(1,161)	734	611	149	(317)	4,290
Earnings (loss) from continuing operations					(357)	(719)	477	414	(20)	(185)	2,134
Earnings (loss) from discontinued operations								(21)		(21)	2,570
Net (loss) earnings	$ 207	$ 429	$ 683	$ (1,339)	$ (357)	$ (719)	$ 477	$ 393	$ (20)	$ (206)	$ 4,704
Basic earnings (loss) from continuing operations per share					$ (0.89)	$ (1.80)	$ 1.18	$ 1.03	$ (0.06)	$ (0.47)	$ 5.12
Basic earnings (loss) from discontinued operations per share								$ (0.06)		$ (0.05)	$ 6.17
Net (loss) earnings - basic	$ 0.51	$ 1.06	$ 1.69	$ (3.34)	$ (0.89)	$ (1.80)	$ 1.18	$ 0.97	$ (0.06)	$ (0.52)	$ 11.29
Diluted earnings (loss) from continuing operations per share					$ (0.89)	$ (1.80)	$ 1.18	$ 1.03	$ (0.06)	$ (0.47)	$ 5.10
Diluted earnings (loss) from discontinued operations per share								$ (0.06)		$ (0.05)	$ 6.15
Net (loss) earnings - diluted	$ 0.51	$ 1.05	$ 1.68	$ (3.34)	$ (0.89)	$ (1.80)	$ 1.18	$ 0.97	$ (0.06)	$ (0.52)	$ 11.25