Income Taxes (Details 4) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Unrecognized Tax Benefits Rollforward (Table Amounts) [Abstract]
Unrecognized tax benefits at beginning of the year	$ 126	$ 429	$ 416
Additions based on tax positions related to the current year	11	19	12
Additions for tax positions of prior years	31	4	61
Reductions for tax positions of prior years	(22)
Settlements	(28)	(326)	(60)
Net change in unrecognized tax benefits	(8)	(303)	13
Unrecognized tax benefits at end of the year	$ 118	$ 126	$ 429