Fair Value Measurements (Details 3) (USD $) In Millions, unless otherwise specified	3 Months Ended				9 Months Ended
	Sep. 30, 2012		Sep. 30, 2011		Sep. 30, 2012		Sep. 30, 2011		Mar. 31, 2012	Mar. 31, 2011
Fixed Maturities [Member] | Available-for-sale Securities [Member]
Roll Forward of Financial Instruments (Assets) Measured at Fair Value on Recurring Basis Using Significant Unobservable Inputs (Level 3)
Fair value, Beginning Balance					$ 5,121		$ 7,489		$ 5,927	$ 7,236
Total realized/unrealized gains (losses) included in net income	(65)	[1],[2],[3]	(50)	[1],[2],[3]	(80)	[1],[2],[3]	(97)	[1],[2],[3]
Total realized/unrealized gains (losses) included in OCI	232	[4]	(149)	[4]	470	[4]	212	[4]
Purchases	151		211		919		290
Settlements	(94)		(154)		(350)		(422)
Sales	(239)		(18)		(587)		(558)
Transfers into Level 3	313	[5]	423	[5]	1,719	[5]	975	[5]
Transfers out of Level 3	(543)	[5]	(96)	[5]	(1,530)	[5]	(486)	[5]
Fair value, Ending Balance	5,682		7,403		5,682		7,403		5,927	7,236
Changes in unrealized gains (losses) included in net income related to financial instruments still held at end of period	(40)	[1],[6]	(50)	[1],[6]	(46)	[1],[6]	(97)	[1],[6]
Fixed Maturities [Member] | Residential Mortgage Backed Securities [Member]
Roll Forward of Financial Instruments (Assets) Measured at Fair Value on Recurring Basis Using Significant Unobservable Inputs (Level 3)
Fair value, Beginning Balance					1,063		1,285		1,208	1,114
Total realized/unrealized gains (losses) included in net income	(17)	[1],[2],[3]		[1],[2],[3]	7	[1],[2],[3]	(9)	[1],[2],[3]
Total realized/unrealized gains (losses) included in OCI	155	[4]	(39)	[4]	202	[4]	(14)	[4]
Purchases	81				364		25
Settlements	(41)		(36)		(111)		(103)
Sales	(56)				(195)		(16)
Transfers into Level 3	1	[5]	68	[5]	1	[5]	82	[5]
Transfers out of Level 3	(39)	[5]		[5]	(39)	[5]	(143)	[5]
Fair value, Ending Balance	1,292		1,107		1,292		1,107		1,208	1,114
Changes in unrealized gains (losses) included in net income related to financial instruments still held at end of period	1	[1],[6]		[1],[6]	1	[1],[6]	(9)	[1],[6]
Fixed Maturities [Member] | US States and Political Subdivisions Debt Securities [Member]
Roll Forward of Financial Instruments (Assets) Measured at Fair Value on Recurring Basis Using Significant Unobservable Inputs (Level 3)
Fair value, Beginning Balance					437		272		650	280
Total realized/unrealized gains (losses) included in net income	(4)	[1],[2],[3]		[1],[2],[3]	(4)	[1],[2],[3]		[1],[2],[3]
Total realized/unrealized gains (losses) included in OCI	14	[4]	46	[4]	38	[4]	55	[4]
Purchases			85		275		85
Settlements
Sales	(22)				(87)		(2)
Transfers into Level 3		[5]		[5]		[5]	4	[5]
Transfers out of Level 3	(434)	[5]		[5]	(455)	[5]	(3)	[5]
Fair value, Ending Balance	204		411		204		411		650	280
Changes in unrealized gains (losses) included in net income related to financial instruments still held at end of period	(4)	[1],[6]		[1],[6]	(4)	[1],[6]		[1],[6]
Fixed Maturities [Member] | Foreign Government Debt Securities [Member]
Roll Forward of Financial Instruments (Assets) Measured at Fair Value on Recurring Basis Using Significant Unobservable Inputs (Level 3)
Fair value, Beginning Balance					49		56		55	51
Total realized/unrealized gains (losses) included in net income		[1],[2],[3]		[1],[2],[3]		[1],[2],[3]		[1],[2],[3]
Total realized/unrealized gains (losses) included in OCI	1	[4]	(1)	[4]	3	[4]		[4]
Purchases	11		1		18		3
Settlements	(1)		(1)		(3)		(3)
Sales	(16)		(1)		(17)		(6)
Transfers into Level 3		[5]	28	[5]		[5]	39	[5]
Transfers out of Level 3		[5]		[5]		[5]	(12)	[5]
Fair value, Ending Balance	50		77		50		77		55	51
Changes in unrealized gains (losses) included in net income related to financial instruments still held at end of period		[1],[6]		[1],[6]		[1],[6]		[1],[6]
Fixed Maturities [Member] | Corporate Debt Securities [Member]
Roll Forward of Financial Instruments (Assets) Measured at Fair Value on Recurring Basis Using Significant Unobservable Inputs (Level 3)
Fair value, Beginning Balance					2,255		2,129		1,805	2,110
Total realized/unrealized gains (losses) included in net income	(4)	[1],[2],[3]	(9)	[1],[2],[3]	(7)	[1],[2],[3]	(37)	[1],[2],[3]
Total realized/unrealized gains (losses) included in OCI	(47)	[4]	(63)	[4]	(50)	[4]	(44)	[4]
Purchases	40		42		205		94
Settlements	(3)		(41)		(56)		(114)
Sales	(9)		(7)		(63)		(141)
Transfers into Level 3	283	[5]	268	[5]	605	[5]	541	[5]
Transfers out of Level 3	(45)	[5]	(81)	[5]	(869)	[5]	(209)	[5]
Fair value, Ending Balance	2,020		2,219		2,020		2,219		1,805	2,110
Changes in unrealized gains (losses) included in net income related to financial instruments still held at end of period	(4)	[1],[6]	(9)	[1],[6]	(4)	[1],[6]	(37)	[1],[6]
Fixed Maturities [Member] | Commercial Mortgage Backed Securities [Member]
Roll Forward of Financial Instruments (Assets) Measured at Fair Value on Recurring Basis Using Significant Unobservable Inputs (Level 3)
Fair value, Beginning Balance					588		689		986	654
Total realized/unrealized gains (losses) included in net income	(33)	[1],[2],[3]		[1],[2],[3]	(67)	[1],[2],[3]	11	[1],[2],[3]
Total realized/unrealized gains (losses) included in OCI	53	[4]	(56)	[4]	112	[4]	91	[4]
Purchases	8		25		21		25
Settlements	(36)		(12)		(106)		(42)
Sales	(127)		(2)		(198)		(317)
Transfers into Level 3	20	[5]	45	[5]	621	[5]	197	[5]
Transfers out of Level 3		[5]		[5]	(100)	[5]		[5]
Fair value, Ending Balance	871		654		871		654		986	654
Changes in unrealized gains (losses) included in net income related to financial instruments still held at end of period	(26)	[1],[6]		[1],[6]	(27)	[1],[6]	11	[1],[6]
Fixed Maturities [Member] | Collateralized Debt Obligations [Member]
Roll Forward of Financial Instruments (Assets) Measured at Fair Value on Recurring Basis Using Significant Unobservable Inputs (Level 3)
Fair value, Beginning Balance					368		2,581		900	2,575
Total realized/unrealized gains (losses) included in net income	(8)	[1],[2],[3]	(26)	[1],[2],[3]	(9)	[1],[2],[3]	(41)	[1],[2],[3]
Total realized/unrealized gains (losses) included in OCI	46	[4]	(34)	[4]	122	[4]	89	[4]
Purchases
Settlements	(8)		(50)		(31)		(128)
Sales					(3)		(66)
Transfers into Level 3		[5]		[5]	483	[5]	30	[5]
Transfers out of Level 3		[5]		[5]		[5]		[5]
Fair value, Ending Balance	930		2,465		930		2,465		900	2,575
Changes in unrealized gains (losses) included in net income related to financial instruments still held at end of period	(8)	[1],[6]	(26)	[1],[6]	(10)	[1],[6]	(41)	[1],[6]
Fixed Maturities [Member] | Asset-backed Securities [Member]
Roll Forward of Financial Instruments (Assets) Measured at Fair Value on Recurring Basis Using Significant Unobservable Inputs (Level 3)
Fair value, Beginning Balance					361		477		323	452
Total realized/unrealized gains (losses) included in net income	1	[1],[2],[3]	(15)	[1],[2],[3]	0	[1],[2],[3]	(21)	[1],[2],[3]
Total realized/unrealized gains (losses) included in OCI	10	[4]	(2)	[4]	43	[4]	35	[4]
Purchases	11		58		36		58
Settlements	(5)		(14)		(43)		(32)
Sales	(9)		(8)		(24)		(10)
Transfers into Level 3	9	[5]	14	[5]	9	[5]	82	[5]
Transfers out of Level 3	(25)	[5]	(15)	[5]	(67)	[5]	(119)	[5]
Fair value, Ending Balance	315		470		315		470		323	452
Changes in unrealized gains (losses) included in net income related to financial instruments still held at end of period	1	[1],[6]	(15)	[1],[6]	(2)	[1],[6]	(21)	[1],[6]
Fixed Maturities, FVO [Member]
Roll Forward of Financial Instruments (Assets) Measured at Fair Value on Recurring Basis Using Significant Unobservable Inputs (Level 3)
Fair value, Beginning Balance					495		522		493	556
Total realized/unrealized gains (losses) included in net income	32	[1],[2],[3]	(24)	[1],[2],[3]	53	[1],[2],[3]	12	[1],[2],[3]
Total realized/unrealized gains (losses) included in OCI		[4]		[4]		[4]		[4]
Purchases
Settlements			(1)				(3)
Sales			(39)		(23)		(39)
Transfers into Level 3		[5]		[5]		[5]		[5]
Transfers out of Level 3		[5]		[5]		[5]		[5]
Fair value, Ending Balance	525		492		525		492		493	556
Changes in unrealized gains (losses) included in net income related to financial instruments still held at end of period	$ 23	[1],[6]	$ (24)	[1],[6]	$ 62	[1],[6]	$ 12	[1],[6]

[1] All amounts in these rows are reported in net realized capital gains/losses. The realized/unrealized gains (losses) included in net income for separate account assets are offset by an equal amount for separate account liabilities, which results in a net zero impact on net income for the Company. All amounts are before income taxes and amortization DAC.

[2] Includes both market and non-market impacts in deriving realized and unrealized gains (losses).

[3] The Company classifies gains and losses on GMWB reinsurance derivatives and Guaranteed Living Benefit embedded derivatives as unrealized gains (losses) for purposes of disclosure in this table because it is impracticable to track on a contract-by-contract basis the realized gains (losses) for these derivatives and embedded derivatives.

[4] All amounts are before income taxes and amortization of DAC.

[5] Transfers in and/or (out) of Level 3 are primarily attributable to the availability of market observable information and the re-evaluation of the observability of pricing inputs.

[6] Amounts presented are for Level 3 only and therefore may not agree to other disclosures included herein.