Fair Value of Assets and Liabilities (Details 3) (USD $) In Millions, unless otherwise specified	3 Months Ended														3 Months Ended						3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012	Mar. 31, 2013 Fixed income securities	Mar. 31, 2012 Fixed income securities	Mar. 31, 2013 U.S. government and agencies	Mar. 31, 2013 Municipal	Mar. 31, 2012 Municipal	Mar. 31, 2013 Corporate	Mar. 31, 2012 Corporate	Mar. 31, 2013 Asset-backed securities ("ABS")	Mar. 31, 2012 Asset-backed securities ("ABS")	Mar. 31, 2012 Residential mortgage-backed securities ("RMBS")	Mar. 31, 2013 Residential mortgage-backed securities ("RMBS")	Dec. 31, 2012 Residential mortgage-backed securities ("RMBS")	Mar. 31, 2013 Commercial mortgage-backed securities ("CMBS")	Mar. 31, 2012 Commercial mortgage-backed securities ("CMBS")	Mar. 31, 2013 Redeemable preferred stock	Dec. 31, 2012 Redeemable preferred stock	Mar. 31, 2012 Redeemable preferred stock	Dec. 31, 2011 Redeemable preferred stock	Mar. 31, 2013 Equity securities	Mar. 31, 2012 Equity securities	Mar. 31, 2013 Free-standing derivatives, net	Mar. 31, 2012 Free-standing derivatives, net	Mar. 31, 2013 Other assets	Dec. 31, 2012 Other assets	Mar. 31, 2012 Other assets	Dec. 31, 2011 Other assets
Fair Value Assets Measured on Recurring Basis Unobservable Input Reconciliation Calculation Rollforward
Balance at beginning of period	$ 3,042	$ 3,095	$ 2,897	$ 3,146	$ 8	$ 965	$ 1,332	$ 1,617	$ 1,405	$ 251	$ 297	$ 51	$ 3	$ 3	$ 52	$ 60	$ 1	$ 1	$ 1	$ 1	$ 171	$ 43	$ (27)	$ (95)	$ 1	$ 1	$ 1	$ 1
Total gains (losses) included in: net income	(3)	32	(11)	15		(24)	(2)	12	5	1	13					(1)					1		7	17
Total gains (losses) included in: OCI	63	54	62	54		54	7	(1)	28	7	13				2	6					1
Transfers into Level 3	49	56	49	56		6		25	56	18
Transfers out of Level 3	(125)	(106)	(125)	(106)			(6)	(125)	(18)		(35)	(47)
Purchases	322	207	321	134			42	264	76	56	16				1							70	1	3
Sales	(605)	(163)	(604)	(163)		(339)	(105)	(199)	(58)	(49)					(17)						1
Settlements	(30)	(49)	(29)	(54)	(1)	(2)	(1)	(17)	(33)	(8)	(5)				(1)	(15)							(1)	5
Balance at end of period	2,713	3,126	2,560	3,082	7	660	1,267	1,576	1,461	276	299	4	3	3	37	50	1	1	1	1	172	113	(20)	(70)	1	1	1	1
Fair value assets and liabilities measured on recurring basis, gain (loss) included in earnings
Total realized and unrealized gains (losses) included in net income, recurring Level 3 assets and liabilities	3	7
Effect to net income included in realized capital gains and losses	(10)	26
Effect to net income included in investment income	7	6
Effect to net income included in interest credited to contract holder funds	(20)	(56)
Effect to net income included in life and annuity contract benefits	26	31
Free-standing derivatives, assets	4	2
Free-standing derivatives, liabilities	24	72
Assets transferred between Level 1 and Level 2	0	0
Liabilities transferred between Level 1 and Level 2	$ 0	$ 0