Income Taxes (Details) (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
Current income tax:
Federal									$ 250	$ (224)	$ 200
State and local									21	13	4
Foreign									23	32	4
Total current income tax									294	(179)	208
Deferred income tax:
Federal									68	540	(13)
State and local									1	(5)	(7)
Foreign									(8)	(6)	(4)
Total deferred income tax									61	513	(24)
Total income tax provision (benefit)									355	350	184
Geographic sources of pretax income (loss)
United States									1,288	1,470	883
Foreign									97	164	37
Income from continuing operations before income tax provision	352	247	399	387	368	446	462	358	1,385	1,634	920
Reconciliation of the income tax provision
Tax at U.S. statutory rate (as a percent)									35.00%	35.00%	35.00%
Changes in taxes resulting from:
Dividend exclusion (as a percent)									(8.90%)	(4.10%)	(7.60%)
Tax-exempt interest income (as a percent)									(1.30%)	(1.00%)	(1.30%)
Tax credits (as a percent)									(3.40%)	(2.50%)	(5.80%)
State taxes, net of federal benefit (as a percent)									1.00%	0.20%	(0.40%)
Net income (loss) attributable to noncontrolling interests (as a percent)									2.70%	(3.40%)	(0.60%)
Other, net (as a percent)									0.50%	(2.70%)	0.70%
Income tax provision (as a percent)									25.60%	21.50%	20.00%
Benefits related to tax planning and completion of certain audits										53
Accumulated earnings of foreign subsidiaries									89
Aggregate U.S. federal taxes not provided on earnings of foreign subsidiaries									$ 9