Investments and Derivative Instruments Level 4 Available-for-Sale Securities (Details) $ in Millions		Sep. 30, 2015 USD ($) Security	Dec. 31, 2014 USD ($)
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Debt Securities, Accumulated Gross Unrealized Loss, before Tax		$ 233	$ 189
Available-for-sale Equity Securities, Amortized Cost Basis		167	525
Available-for-sale Securities, Equity Securities		167	514
Available-for-sale Securities, Accumulated Gross Unrealized Loss, before Tax		245	208
Available-for-sale Securities, Accumulated Gross Unrealized Gain, before Tax		1,737	2,374
Available-for-sale Securities, Amortized Cost
One year or less, amortized cost		921	1,031
Over one year through five years, amortized cost		4,943	4,902
Over five years through ten years, amortized cost		3,713	3,345
Over ten years, amortized cost		8,333	8,116
Available-for-sale Securities, Fair Value
One year or less, fair value		928	1,043
Over one year through five years, fair value		5,132	5,168
Over five years through ten years, fair value		3,808	3,501
Over ten years, fair value		9,368	9,661
Available-for-sale Securities, Debt Maturities, Amortized Cost Basis		23,587	23,260
Available-for-sale Securities, Debt Securities		25,078	25,436
Available-for-sale Securities, Debt Maturities, without Single Maturity Date, Amortized Cost Basis		5,677	5,866
Available-for-sale Securities, Debt Maturities, without Single Maturity Date, Fair Value		5,842	6,063
Available-for-sale Securities, Continuous Unrealized Loss Position [Abstract]
Available-for-sale Securities, Amortized Cost Basis		23,754	23,535
Available-for-sale Securities			25,702
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Amortized Cost		5,526	2,714
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value		5,374	2,648
Available-for-sale Securities Continuous Unrealized Loss Position Twelve Months or Longer Amortized Cost		1,587	2,386
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value		1,493	2,245
Available-for-sale Securities Continuous Unrealized Loss Position Amortized Cost		7,113	5,100
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value		6,867	4,893
Available-for-sale Debt Securities, Accumulated Gross Unrealized Gain, before Tax		$ 1,725	2,364
Number of Securities Included in AFS Securities in Unrealized Loss Position | Security		2,487
Percentage of Gross Unrealized Losses Depressed Less than Twenty Percent of Cost or Amortized Cost		89.00%
Available-for-sale Equity Securities, Accumulated Gross Unrealized Gain, before Tax		$ 12	10
Available-for-sale Equity Securities, Accumulated Gross Unrealized Loss, before Tax		12	19
Fixed maturities available-for-sale, excluding mortgage-backed and asset-backed securities [Member]
Available-for-sale Securities, Fair Value
Available-for-sale Securities, Debt Maturities, Amortized Cost Basis		17,910	17,394
Available-for-sale Securities, Debt Securities		19,236	19,373
Asset-backed Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Debt Securities, Accumulated Gross Unrealized Loss, before Tax		32	30
Available-for-sale Securities, Fair Value
Available-for-sale Securities, Debt Maturities, Amortized Cost Basis		953	1,181
Available-for-sale Securities, Debt Securities		943	1,171
Available-for-sale Securities, Continuous Unrealized Loss Position [Abstract]
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Amortized Cost		268	368
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value		267	367
Available-for-sale Securities Continuous Unrealized Loss Position Twelve Months or Longer Amortized Cost		253	340
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value		222	311
Available-for-sale Securities Continuous Unrealized Loss Position Amortized Cost		521	708
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value		489	678
Available-for-sale Debt Securities, Accumulated Gross Unrealized Gain, before Tax		22	20
Accumulated Other Comprehensive Income (Loss), Other than Temporary Impairment, Not Credit Loss, Net of Tax, Available-for-sale, Debt Securities		0	0
Collateralized Debt Obligations [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Debt Securities, Accumulated Gross Unrealized Loss, before Tax		8	20
Available-for-sale Securities, Fair Value
Available-for-sale Securities, Debt Maturities, Amortized Cost Basis		1,318	1,083
Available-for-sale Securities, Debt Securities		1,386	1,148
Available-for-sale Securities, Continuous Unrealized Loss Position [Abstract]
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Amortized Cost	[1]	521	123
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value	[1]	519	122
Available-for-sale Securities Continuous Unrealized Loss Position Twelve Months or Longer Amortized Cost	[1]	524	771
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value	[1]	517	753
Available-for-sale Securities Continuous Unrealized Loss Position Amortized Cost	[1]	1,045	894
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value	[1]	1,036	875
Available-for-sale Debt Securities, Accumulated Gross Unrealized Gain, before Tax		77	84
Accumulated Other Comprehensive Income (Loss), Other than Temporary Impairment, Not Credit Loss, Net of Tax, Available-for-sale, Debt Securities		0	0
Commercial Mortgage Backed Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Debt Securities, Accumulated Gross Unrealized Loss, before Tax		12	7
Available-for-sale Securities, Fair Value
Available-for-sale Securities, Debt Maturities, Amortized Cost Basis		1,935	1,797
Available-for-sale Securities, Debt Securities		2,001	1,887
Available-for-sale Securities, Continuous Unrealized Loss Position [Abstract]
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Amortized Cost		388	109
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value		380	108
Available-for-sale Securities Continuous Unrealized Loss Position Twelve Months or Longer Amortized Cost		94	194
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value		90	188
Available-for-sale Securities Continuous Unrealized Loss Position Amortized Cost		482	303
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value		470	296
Available-for-sale Debt Securities, Accumulated Gross Unrealized Gain, before Tax		78	97
Accumulated Other Comprehensive Income (Loss), Other than Temporary Impairment, Not Credit Loss, Net of Tax, Available-for-sale, Debt Securities		3	3
Corporate Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Debt Securities, Accumulated Gross Unrealized Loss, before Tax		150	109
Available-for-sale Securities, Fair Value
Available-for-sale Securities, Debt Maturities, Amortized Cost Basis		14,404	14,166
Available-for-sale Securities, Debt Securities		15,428	15,742
Available-for-sale Securities, Continuous Unrealized Loss Position [Abstract]
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Amortized Cost		3,488	1,542
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value		3,368	1,491
Available-for-sale Securities Continuous Unrealized Loss Position Twelve Months or Longer Amortized Cost		366	661
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value		336	603
Available-for-sale Securities Continuous Unrealized Loss Position Amortized Cost		3,854	2,203
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value		3,704	2,094
Available-for-sale Debt Securities, Accumulated Gross Unrealized Gain, before Tax		1,174	1,685
Accumulated Other Comprehensive Income (Loss), Other than Temporary Impairment, Not Credit Loss, Net of Tax, Available-for-sale, Debt Securities		1	3
Foreign Government Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Debt Securities, Accumulated Gross Unrealized Loss, before Tax		11	9
Available-for-sale Securities, Fair Value
Available-for-sale Securities, Debt Maturities, Amortized Cost Basis		335	576
Available-for-sale Securities, Debt Securities		341	602
Available-for-sale Securities, Continuous Unrealized Loss Position [Abstract]
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Amortized Cost		116	145
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value		108	140
Available-for-sale Securities Continuous Unrealized Loss Position Twelve Months or Longer Amortized Cost		30	68
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value		27	64
Available-for-sale Securities Continuous Unrealized Loss Position Amortized Cost		146	213
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value		135	204
Available-for-sale Debt Securities, Accumulated Gross Unrealized Gain, before Tax		17	35
Accumulated Other Comprehensive Income (Loss), Other than Temporary Impairment, Not Credit Loss, Net of Tax, Available-for-sale, Debt Securities		0	0
Municipal Bonds [Member]
Available-for-sale Securities, Continuous Unrealized Loss Position [Abstract]
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Amortized Cost		278	14
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value		270	14
Available-for-sale Securities Continuous Unrealized Loss Position Twelve Months or Longer Amortized Cost		4	13
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value		3	12
Available-for-sale Securities Continuous Unrealized Loss Position Amortized Cost		282	27
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value		273	26
US States and Political Subdivisions Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Debt Securities, Accumulated Gross Unrealized Loss, before Tax		9	1
Available-for-sale Securities, Fair Value
Available-for-sale Securities, Debt Maturities, Amortized Cost Basis		1,067	935
Available-for-sale Securities, Debt Securities		1,147	1,052
Available-for-sale Securities, Continuous Unrealized Loss Position [Abstract]
Available-for-sale Debt Securities, Accumulated Gross Unrealized Gain, before Tax		89	118
Accumulated Other Comprehensive Income (Loss), Other than Temporary Impairment, Not Credit Loss, Net of Tax, Available-for-sale, Debt Securities		0	0
Residential Mortgage Backed Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Debt Securities, Accumulated Gross Unrealized Loss, before Tax		10	12
Available-for-sale Securities, Fair Value
Available-for-sale Securities, Debt Maturities, Amortized Cost Basis		1,471	1,805
Available-for-sale Securities, Debt Securities		1,512	1,857
Available-for-sale Securities, Continuous Unrealized Loss Position [Abstract]
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Amortized Cost		158	148
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value		157	147
Available-for-sale Securities Continuous Unrealized Loss Position Twelve Months or Longer Amortized Cost		250	229
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value		241	218
Available-for-sale Securities Continuous Unrealized Loss Position Amortized Cost		408	377
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value		398	365
Available-for-sale Debt Securities, Accumulated Gross Unrealized Gain, before Tax		51	64
Accumulated Other Comprehensive Income (Loss), Other than Temporary Impairment, Not Credit Loss, Net of Tax, Available-for-sale, Debt Securities		0	0
US Treasury Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Debt Securities, Accumulated Gross Unrealized Loss, before Tax		1	1
Available-for-sale Securities, Fair Value
Available-for-sale Securities, Debt Maturities, Amortized Cost Basis		2,104	1,717
Available-for-sale Securities, Debt Securities		2,320	1,977
Available-for-sale Securities, Continuous Unrealized Loss Position [Abstract]
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Amortized Cost		278	184
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value		277	184
Available-for-sale Securities Continuous Unrealized Loss Position Twelve Months or Longer Amortized Cost		8	18
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value		8	17
Available-for-sale Securities Continuous Unrealized Loss Position Amortized Cost		286	202
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value		285	201
Available-for-sale Debt Securities, Accumulated Gross Unrealized Gain, before Tax		217	261
Accumulated Other Comprehensive Income (Loss), Other than Temporary Impairment, Not Credit Loss, Net of Tax, Available-for-sale, Debt Securities		0	0
Debt Securities [Member]
Available-for-sale Securities, Continuous Unrealized Loss Position [Abstract]
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Amortized Cost		5,495	2,633
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value		5,346	2,573
Available-for-sale Securities Continuous Unrealized Loss Position Twelve Months or Longer Amortized Cost		1,529	2,294
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value		1,444	2,166
Available-for-sale Securities Continuous Unrealized Loss Position Amortized Cost		7,024	4,927
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value		6,790	4,739
Accumulated Other Comprehensive Income (Loss), Other than Temporary Impairment, Not Credit Loss, Net of Tax, Available-for-sale, Debt Securities		4	6
Available-for-sale Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Equity Securities, Amortized Cost Basis		167
Available-for-sale Securities, Equity Securities		167	266
Available-for-sale Securities, Continuous Unrealized Loss Position [Abstract]
Available-for-sale Securities		25,245
Accumulated Other Comprehensive Income (Loss), Other than Temporary Impairment, Not Credit Loss, Net of Tax, Available-for-sale, Debt Securities		4	6
Equity Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Equity Securities, Amortized Cost Basis			275
Available-for-sale Securities, Continuous Unrealized Loss Position [Abstract]
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Amortized Cost		31	81
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value		28	75
Available-for-sale Securities Continuous Unrealized Loss Position Twelve Months or Longer Amortized Cost		58	92
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value		49	79
Available-for-sale Securities Continuous Unrealized Loss Position Amortized Cost		89	173
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value		77	154
Accumulated Other Comprehensive Income (Loss), Other than Temporary Impairment, Not Credit Loss, Net of Tax, Available-for-sale, Debt Securities		0	0
Equity Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Equity Securities, Amortized Cost Basis		0	250
Available-for-sale Securities, Equity Securities		$ 0	$ 248

[1] Unrealized losses exclude the change in fair value of bifurcated embedded derivatives within certain securities, for which changes in fair value are recorded in net realized capital gains (losses).