Income Taxes (Schedule of Reconciliation of Unrecognized Tax Benefits Included in Uncertain Tax Positions) (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Income Tax Disclosure [Abstract]
As of the beginning of the year	$ 244	$ 208	$ 195
Increases in tax positions for the current year	0	0	19
Increases in tax positions for prior years	37	85	39
Decreases in tax positions of prior years	(54)	(48)	38
Decreases due to settlements	(16)	(1)	7
As of the end of the year	211	244	208
Total unrecognized tax benefits that, if recognized, would impact the effective tax rate	230	264	208
Total amount of interest and penalties recognized in the consolidated statement of operations	(1)	12	7
Total amount of interest and penalties recognized in the consolidated balance sheet	$ 55	$ 56	$ 45