Statement of Consolidated Shareholders' Equity (Unaudited) (USD $) In Millions, unless otherwise specified	Total	Series D Preferred Stock	Common Stock	Paid-In Capital	Retained Earnings	Treasury Stock	Accumulated Other Comprehensive Loss [Member]
Beginning Balance at Dec. 31, 2010	$ 24,377	$ 1,227	$ 240	$ 8,864	$ 14,223	$ (36)	$ (141)
Net income	1,134				1,134
Commodity hedges, net of tax	(304)						(304)
Cash dividends:
Preferred	(19)				(19)
Common ($0.15 and $0.17 per share for 2010 & 2011 respectively)	(58)				(58)
Common stock activity, net	16			16
Treasury stock activity, net	6			3		3
Compensation expense	45			45
Other	1				1
Ending Balance at Mar. 31, 2011	25,198	1,227	240	8,928	15,281	(33)	(445)
Beginning Balance at Dec. 31, 2011	28,993	1,227	241	9,066	18,500	(32)	(9)
Net income	797				797
Commodity hedges, net of tax	(33)						(33)
Cash dividends:
Preferred	(19)				(19)
Common ($0.15 and $0.17 per share for 2010 & 2011 respectively)	(65)				(65)
Common stock activity, net	(5)			(5)
Treasury stock activity, net	1					1
Compensation expense	46			46
Ending Balance at Mar. 31, 2012	$ 29,715	$ 1,227	$ 241	$ 9,107	$ 19,213	$ (31)	$ (42)