Principles Of Consolidation And Other Matters (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2012	Mar. 31, 2011	Dec. 31, 2011
Equity method gains (losses)	$ 20	$ 18
Equity method investments	96
Remaining capital commitment	67
Effective tax rate	30.20%	28.60%
Gross unrecognized tax benefits	144		143
Excluding Tax Benefit [Member]
Effective tax rate		31.60%
Minimum [Member] | Significant Change in Unrecognized Tax Benefits is Reasonably Possible Estimated Range of Change Upper Limit [Member]
Projection of unrecognized tax benefit in twelve months, lower bound	0
Maximum [Member] | Significant Change in Unrecognized Tax Benefits is Reasonably Possible Estimated Range of Change Upper Limit [Member]
Projection of unrecognized tax benefit in twelve months, upper bound	$ 60