Statement of Consolidated Shareholders' Equity (USD $) In Millions, unless otherwise specified	Total	Series D Preferred Stock [Member]	Common Stock [Member]	Paid-In Capital [Member]	Retained Earnings [Member]	Treasury Stock [Member]	Accumulated Other Comprehensive Income (Loss) [Member]
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)
Dividends:
Preferred	(19)				(19)
Common ($0.17 and $0.20 per share for 2012 and 2013 respectively)	(65)				(65)
Common stock activity, net	(5)			(5)
Treasury stock activity, net	1					1
Compensation expense	46			46
Balance at Mar. 31, 2012	29,715	1,227	241	9,107	19,213	(31)	(42)
Balance at Dec. 31, 2012	31,331	1,227	245	9,859	20,161	(30)	(131)
NET INCOME	717				717
Commodity hedges, net of tax	(2)						(2)
Dividends:
Preferred	(19)				(19)
Common ($0.17 and $0.20 per share for 2012 and 2013 respectively)	(78)				(78)
Common stock activity, net	(8)			(8)
Compensation expense	46			46
Balance at Mar. 31, 2013	$ 31,987	$ 1,227	$ 245	$ 9,897	$ 20,781	$ (30)	$ (133)