Noncontrolling Interests (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Activity for equity attributable to noncontrolling interests
Beginning Balance	$ 105,811	$ 92,561
Net Income	27,008	19,136	10,563
Ending Balance	122,181	105,811	92,561
Noncontrolling Interest [Member]
Activity for equity attributable to noncontrolling interests
Beginning Balance	730	647	469
Net Income	113	112	80
Distributions to noncontrolling interests	(71)	(72)	(71)
Other changes, net	27	43	169
Ending Balance	$ 799	$ 730	$ 647