Fair Value of Assets and Liabilities (Details 3) (USD $) In Millions, unless otherwise specified	3 Months Ended		6 Months Ended		3 Months Ended		6 Months Ended		3 Months Ended	6 Months Ended			3 Months Ended		6 Months Ended		3 Months Ended		6 Months Ended		3 Months Ended		6 Months Ended							3 Months Ended		6 Months Ended		3 Months Ended	6 Months Ended				3 Months Ended		6 Months Ended		3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013 Fixed income securities	Jun. 30, 2012 Fixed income securities	Jun. 30, 2013 Fixed income securities	Jun. 30, 2012 Fixed income securities	Jun. 30, 2012 U.S. government and agencies	Jun. 30, 2013 U.S. government and agencies	Jun. 30, 2012 U.S. government and agencies	Mar. 31, 2013 U.S. government and agencies	Jun. 30, 2013 Municipal	Jun. 30, 2012 Municipal	Jun. 30, 2013 Municipal	Jun. 30, 2012 Municipal	Jun. 30, 2013 Corporate	Jun. 30, 2012 Corporate	Jun. 30, 2013 Corporate	Jun. 30, 2012 Corporate	Jun. 30, 2013 Asset-backed securities ("ABS")	Jun. 30, 2012 Asset-backed securities ("ABS")	Jun. 30, 2013 Asset-backed securities ("ABS")	Jun. 30, 2012 Asset-backed securities ("ABS")	Jun. 30, 2012 Residential mortgage-backed securities ("RMBS")	Jun. 30, 2013 Residential mortgage-backed securities ("RMBS")	Mar. 31, 2013 Residential mortgage-backed securities ("RMBS")	Dec. 31, 2012 Residential mortgage-backed securities ("RMBS")	Mar. 31, 2012 Residential mortgage-backed securities ("RMBS")	Jun. 30, 2013 Commercial mortgage-backed securities ("CMBS")	Jun. 30, 2012 Commercial mortgage-backed securities ("CMBS")	Jun. 30, 2013 Commercial mortgage-backed securities ("CMBS")	Jun. 30, 2012 Commercial mortgage-backed securities ("CMBS")	Jun. 30, 2012 Redeemable preferred stock	Jun. 30, 2012 Redeemable preferred stock	Jun. 30, 2013 Redeemable preferred stock	Mar. 31, 2013 Redeemable preferred stock	Dec. 31, 2012 Redeemable preferred stock	Jun. 30, 2013 Equity securities	Jun. 30, 2012 Equity securities	Jun. 30, 2013 Equity securities	Jun. 30, 2012 Equity securities	Jun. 30, 2013 Free-standing derivatives, net	Jun. 30, 2012 Free-standing derivatives, net	Jun. 30, 2013 Free-standing derivatives, net	Jun. 30, 2012 Free-standing derivatives, net	Jun. 30, 2013 Other assets	Mar. 31, 2013 Other assets	Dec. 31, 2012 Other assets	Jun. 30, 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	$ 2,713	$ 3,126	$ 3,042	$ 3,095	$ 2,560	$ 3,082	$ 2,897	$ 3,146		$ 8		$ 7	$ 660	$ 1,267	$ 965	$ 1,332	$ 1,576	$ 1,461	$ 1,617	$ 1,405	$ 276	$ 299	$ 251	$ 297	$ 51	$ 3	$ 3	$ 3	$ 4	$ 37	$ 50	$ 52	$ 60	$ 1	$ 1	$ 1	$ 1	$ 1	$ 172	$ 113	$ 171	$ 43	$ (20)	$ (70)	$ (27)	$ (95)	$ 1	$ 1	$ 1	$ 1	$ 1	$ 1
Total gains (losses) included in: net income	19	5	16	37	3	12	(8)	27					(4)	(4)	(28)	(6)	9	1	21	6	(1)	16		29						(1)	(1)	(1)	(2)						1	(4)	2	(4)	15	(3)	22	14
Total gains (losses) included in: OCI	(35)	12	28	66	(35)	6	27	60					(5)	10	49	17	(38)	(5)	(39)	23	8	(1)	15	12							2	2	8							6	1	6
Transfers into Level 3	38	88	87	144	38	88	87	144	8		8				6		38	80	63	136			18
Transfers out of Level 3	(172)	(61)	(297)	(167)	(172)	(61)	(297)	(167)					(6)	(20)	(6)	(26)	(150)	(20)	(275)	(38)	(16)	(16)	(16)	(51)	(47)						(5)		(5)
Purchases	223	211	545	418	223	116	544	250					52		52	42	96	55	360	131	70	58	126	74						5	2	6	2	1	1					92		162		3	1	6
Sales	(281)	(169)	(886)	(332)	(233)	(154)	(837)	(317)					(124)	(100)	(463)	(205)	(77)	(41)	(276)	(99)	(32)	(11)	(81)	(11)							(1)	(17)	(1)	(1)	(1)				(48)	(15)	(49)	(15)
Settlements	(110)	(28)	(140)	(77)	(108)	(27)	(137)	(81)		(1)			(20)	(9)	(22)	(10)	(71)	(7)	(88)	(40)	(17)	(11)	(25)	(16)								(1)	(15)										(2)	(1)	(3)	4
Balance at end of period	2,395	3,184	2,395	3,184	2,276	3,062	2,276	3,062	8	7	8	7	553	1,144	553	1,144	1,383	1,524	1,383	1,524	288	334	288	334	4	3	3	3	4	41	47	41	47	1	1	1	1	1	125	192	125	192	(7)	(71)	(7)	(71)	1	1	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	76	21	79	28
Effect to net income included in realized capital gains and losses	12	(3)	2	23
Effect to net income included in investment income	5	9	12	15
Effect to net income included in interest credited to contract holder funds	39	32	19	(24)
Effect to net income included in life and annuity contract benefits	20	(17)	46	14
Free-standing derivatives, assets	6	1	6	1
Free-standing derivatives, liabilities	13	72	13	72
Assets transferred between Level 1 and Level 2	0		0
Liabilities transferred between Level 1 and Level 2	$ 0		$ 0