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	1,333				1,333
Commodity hedges, net of tax	(80)						(80)
Dividends:
Preferred	(57)				(57)
Common	(198)				(198)
Common shares issued	601		3	598
Common stock activity, net	(11)		1	(12)
Treasury stock activity, net	3			1		2
Compensation expense	130			130
Balance at Sep. 30, 2012	30,714	1,227	245	9,783	19,578	(30)	(89)
Balance at Dec. 31, 2012	31,331	1,227	245	9,859	20,161	(30)	(131)
NET INCOME	2,058				2,058
Commodity hedges, net of tax	8						8
Dividends:
Preferred	(44)				(44)
Common	(237)				(237)
Common shares issued	1,227		9	1,218
Common stock activity, net	(11)		1	(12)
Treasury stock activity, net	(251)			(1)		(250)
Conversion of Series D preferred stock	(1,227)	(1,227)
Compensation expense	135			135
Other	(8)			(8)
Balance at Sep. 30, 2013	$ 32,981		$ 255	$ 11,191	$ 21,938	$ (280)	$ (123)