Condensed Consolidated Statement of Changes in Equity (USD $) In Millions	Total	Redeemable Noncontrolling Interest [Member]	Members Capital [Member]	Accumulated Other Comprehensive Income (Loss) [Member]	Noncontrolling Interests [Member]
Balance at Dec. 31, 2011	$ 30,081	$ 184	$ 29,798	$ (78)	$ 361
Compensation plans	3		3
Contributions from (distributions to) noncontrolling interests, net	(47)	(10)			(47)
Purchases of subsidiary shares from noncontrolling interests		(47)
Other	(20)		4		(24)
Other comprehensive income (loss)	1			1
Net income (loss)	409	8	385		24
Balance at Mar. 31, 2012	30,427	135	30,190	(77)	314
Balance at Dec. 31, 2012	32,254	131	31,900	(65)	419
Compensation plans	7		7
Dividends declared	(3,200)		(3,200)
Contributions from (distributions to) noncontrolling interests, net	(39)	(9)			(39)
Other	(170)		(172)		2
Other comprehensive income (loss)	(22)			(22)
Net income (loss)	405	6	355		50
Balance at Mar. 31, 2013	$ 29,235	$ 128	$ 28,890	$ (87)	$ 432