Fair Value of Assets and Liabilities (Details 3) (USD $) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended		3 Months Ended		9 Months Ended		3 Months Ended		9 Months Ended		3 Months Ended		9 Months Ended		3 Months Ended	9 Months Ended		3 Months Ended		9 Months Ended		3 Months Ended		9 Months Ended							3 Months Ended	9 Months Ended			3 Months Ended		9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012 Fixed income securities	Sep. 30, 2011 Fixed income securities	Sep. 30, 2012 Fixed income securities	Sep. 30, 2011 Fixed income securities	Sep. 30, 2012 Municipal	Sep. 30, 2011 Municipal	Sep. 30, 2012 Municipal	Sep. 30, 2011 Municipal	Sep. 30, 2012 Corporate	Sep. 30, 2011 Corporate	Sep. 30, 2012 Corporate	Sep. 30, 2011 Corporate	Sep. 30, 2011 RMBS	Sep. 30, 2012 RMBS	Sep. 30, 2011 RMBS	Sep. 30, 2012 CMBS	Sep. 30, 2011 CMBS	Sep. 30, 2012 CMBS	Sep. 30, 2011 CMBS	Sep. 30, 2012 ABS	Sep. 30, 2011 ABS	Sep. 30, 2012 ABS	Sep. 30, 2011 ABS	Sep. 30, 2012 Redeemable preferred stock	Jun. 30, 2012 Redeemable preferred stock	Sep. 30, 2011 Redeemable preferred stock	Jun. 30, 2011 Redeemable preferred stock	Dec. 31, 2010 Redeemable preferred stock	Sep. 30, 2012 Equity securities	Sep. 30, 2012 Equity securities	Sep. 30, 2011 Equity securities	Jun. 30, 2011 Equity securities	Sep. 30, 2012 Free-standing derivatives, net	Sep. 30, 2011 Free-standing derivatives, net	Sep. 30, 2012 Free-standing derivatives, net	Sep. 30, 2011 Free-standing derivatives, net	Sep. 30, 2012 Other assets	Jun. 30, 2012 Other assets	Dec. 31, 2011 Other assets	Sep. 30, 2011 Other assets	Jun. 30, 2011 Other assets	Dec. 31, 2010 Other assets
Rollforward of Level 3 assets held at fair value on a recurring basis
Balance at beginning of period	$ 2,007	$ 5,485	$ 1,965	$ 6,322	$ 2,062	$ 5,538	$ 2,038	$ 6,369	$ 363	$ 433	$ 387	$ 601	$ 1,403	$ 1,567	$ 1,319	$ 1,760	$ 847	$ 47	$ 1,189	$ 21	$ 904	$ 30	$ 844	$ 274	$ 1,786	$ 254	$ 1,974	$ 1	$ 1	$ 1	$ 1	$ 1	$ 15	$ 14	$ 29	$ 13	$ (71)	$ (67)	$ (88)	$ (77)	$ 1	$ 1	$ 1	$ 1	$ 1	$ 1
Total gains (losses) included in: net income	8	(83)	54	(97)	(1)	(43)	33	(55)					9	(6)	16	27			(57)	(1)		(3)	(42)	(9)	(37)	20	17						(1)	(1)	(5)		10	(40)	22	(37)
Total gains (losses) included in: OCI	79	(97)	122	153	79	(97)	121	153	7	(2)	9	13	38	(20)	58	(2)	2		78	1	(4)	9	111	33	(73)	45	(47)							1
Transfers into Level 3	169	3	302	248	169	3	302	248	53		53		74	3	207	183							65	42		42
Transfers out of Level 3	(4)	(1,824)	(71)	(2,118)	(4)	(1,824)	(71)	(2,108)		(22)	(10)	(33)		(82)	(10)	(193)	(764)	(47)	(821)		(868)		(878)	(4)	(88)	(4)	(183)								(10)
Purchases	75	279	131	438	54	274	99	418				10	54	207	98	262									67		146	1						5			21	5	27	20
Sales	(275)	(60)	(382)	(1,021)	(275)	(60)	(377)	(1,020)	(12)	(11)	(28)	(193)	(113)	(48)	(187)	(408)			(222)				(66)	(150)	(1)	(161)	(131)	(1)						(5)	(1)
Settlements	(35)	(121)	(97)	(343)	(45)	(120)	(106)	(334)					(45)	(43)	(81)	(51)	(4)		(86)			(15)	(2)		(73)	(10)	(195)										10	(1)	9	(9)
Balance at end of period	2,024	3,582	2,024	3,582	2,039	3,671	2,039	3,671	411	398	411	398	1,420	1,578	1,420	1,578	81		81	21	32	21	32	186	1,581	186	1,581	1	1	1	1	1	14	14	13	13	(30)	(103)	(30)	(103)	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	168	(81)	205	(121)
Effect to net income included in realized capital gains and losses	2	(93)	37	(122)
Effect to net income included in investment income	5	13	17	28
Effect to net income included in interest credited to contract holder funds	143	54	119	(9)
Effect to net income included in contract benefits	18	(55)	32	(18)
Free-standing derivatives, assets	2	1	2	1
Free-standing derivatives, liabilities	$ 32	$ 104	$ 32	$ 104