Comprehensive Income (Details 3) (USD $) In Millions, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2011	Sep. 30, 2011	Jun. 30, 2011	Mar. 31, 2011	Dec. 31, 2010	Sep. 30, 2010	Jun. 30, 2010	Mar. 31, 2010	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Comprehensive income:
Net income	$ 281	$ (180)	$ (107)	$ 274	$ 254	$ 275	$ (31)	$ 162	$ 268	$ 660	$ 446
Change in other comprehensive (loss) income, net of tax									(61)	91	516
Less: Cumulative effect of accounting changes, net of tax											(101)
Less: Unrealized gains transferred to the noncontrolling interest, net of tax										(15)
Total comprehensive income									207	766	1,063
Less: Noncontrolling interest in consolidated entity - Exchange									90	599	856
Total comprehensive income - Indemnity									$ 117	$ 167	$ 207