Investments and Derivative Instruments Level 4 Available-for-Sale Securities (Details) $ in Millions		3 Months Ended			6 Months Ended			12 Months Ended
		Jun. 30, 2016 USD ($) securities		Jun. 30, 2015 USD ($)	Jun. 30, 2016 USD ($) securities		Jun. 30, 2015 USD ($)	Dec. 31, 2015 USD ($)
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale, Securities in Unrealized Loss Positions, Qualitative Disclosure, Number of Positions | securities		2,917			2,917
Derivative, Gain (Loss) on Derivative, Net		$ (17)		$ (27)	$ (48)		$ (30)
Available-for-sale Securities, Fair Value to Amortized Cost Basis [Abstract]
Available-for-sale Debt Securities, Amortized Cost Basis		56,722			56,722			$ 56,965
Available-for-sale Debt Securities, Accumulated Gross Unrealized Gain, before Tax		4,779			4,779			2,892
Available-for-sale Debt Securities, Accumulated Gross Unrealized Loss, before Tax		261			261			658
Available-for-sale Equity Securities, Amortized Cost Basis		772			772			1,135
Available-for-sale Securities, Equity Securities		827			827			1,121
Available-for-sale Securities, Accumulated Gross Unrealized Gain, before Tax		4,858			4,858			2,930
Available-for-sale Securities, Accumulated Gross Unrealized Loss, before Tax		285			285			699
Available-for-sale Securities, Amortized Cost Basis		57,494			57,494			57,807
Available-for-sale Securities								60,035
Available-for-sale Securities, Debt Maturities, Amortized Cost Basis, Fiscal Year Maturity [Abstract]
One year or less, amortized cost		2,030			2,030			2,373
Over one year through five years, amortized cost		10,116			10,116			10,929
Over five years through ten years, amortized cost		9,292			9,292			9,322
Over ten years, amortized cost		19,936			19,936			20,178
Mortgage-backed and asset-backed securities, amortized cost		15,348			15,348			14,163
Total fixed maturities, AFS, amortized cost		56,722			56,722			56,965
Available-for-sale Securities, Debt Maturities, Fair Value, Fiscal Year Maturity [Abstract]
One year or less, fair value		2,048			2,048			2,405
Over one year through five years, fair value		10,575			10,575			11,200
Over five years through ten years, fair value		9,866			9,866			9,497
Over ten years, fair value		23,087			23,087			21,794
Mortgage-backed and asset-backed securities, fair value		15,665			15,665			14,300
Total fixed maturities, AFS, fair value		61,241			61,241			59,196
Available-for-sale Securities, Continuous Unrealized Loss Position [Abstract]
Less Than 12 Months, Fair Value		4,892			4,892			18,569
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss		107			107			526
Available-for-sale Securities Continuous Unrealized Loss Position Twelve Months or Longer Amortized Cost		4,040			4,040			3,072
12 Months or More, Fair Value		3,862			3,862			2,896
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss		178			178			173
Amortized Cost		9,038			9,038			22,167
Fair Value		8,754			8,754			21,465
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss		285			285			699
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Amortized Cost		4,998			4,998			19,095
Gain (Loss) on Investments, Excluding Other than Temporary Impairments		$ 60		20	$ (72)		37
Percentage of Gross Unrealized Losses Depressed Less than Twenty Percent of Cost or Amortized Cost		89.00%			89.00%
Assets, Fair Value Disclosure		$ 180,046			$ 180,046			181,633
Asset-backed Securities [Member]
Available-for-sale Securities, Fair Value to Amortized Cost Basis [Abstract]
Available-for-sale Debt Securities, Amortized Cost Basis		2,782			2,782			2,520
Available-for-sale Debt Securities, Accumulated Gross Unrealized Gain, before Tax		36			36			24
Available-for-sale Debt Securities, Accumulated Gross Unrealized Loss, before Tax		41			41			45
Accumulated Other Comprehensive Income (Loss), Other than Temporary Impairment, Not Credit Loss, Net of Tax, Available-for-sale, Debt Securities	[1]	0			0			0
Available-for-sale Securities, Debt Maturities, Amortized Cost Basis, Fiscal Year Maturity [Abstract]
Total fixed maturities, AFS, amortized cost		2,782			2,782			2,520
Available-for-sale Securities, Debt Maturities, Fair Value, Fiscal Year Maturity [Abstract]
Total fixed maturities, AFS, fair value		2,777			2,777			2,499
Available-for-sale Securities, Continuous Unrealized Loss Position [Abstract]
Less Than 12 Months, Fair Value		755			755			1,609
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss		3			3			10
Available-for-sale Securities Continuous Unrealized Loss Position Twelve Months or Longer Amortized Cost		427			427			357
12 Months or More, Fair Value		389			389			322
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss		38			38			35
Amortized Cost		1,185			1,185			1,976
Fair Value		1,144			1,144			1,931
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss		41			41			45
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Amortized Cost		758			758			1,619
Collateralized Debt Obligations [Member]
Available-for-sale Securities, Fair Value to Amortized Cost Basis [Abstract]
Available-for-sale Debt Securities, Amortized Cost Basis	[2]	2,829			2,829			2,989
Available-for-sale Debt Securities, Accumulated Gross Unrealized Gain, before Tax	[2]	63			63			75
Available-for-sale Debt Securities, Accumulated Gross Unrealized Loss, before Tax	[2]	26			26			23
Accumulated Other Comprehensive Income (Loss), Other than Temporary Impairment, Not Credit Loss, Net of Tax, Available-for-sale, Debt Securities	[1],[2]	0			0			0
Available-for-sale Securities, Debt Maturities, Amortized Cost Basis, Fiscal Year Maturity [Abstract]
Total fixed maturities, AFS, amortized cost	[2]	2,829			2,829			2,989
Available-for-sale Securities, Debt Maturities, Fair Value, Fiscal Year Maturity [Abstract]
Total fixed maturities, AFS, fair value	[2]	2,867			2,867			3,038
Available-for-sale Securities, Continuous Unrealized Loss Position [Abstract]
Less Than 12 Months, Fair Value	[3]	997			997			1,154
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	[3]	10			10			10
Available-for-sale Securities Continuous Unrealized Loss Position Twelve Months or Longer Amortized Cost	[3]	1,262			1,262			1,243
12 Months or More, Fair Value	[3]	1,246			1,246			1,227
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	[3]	16			16			13
Amortized Cost	[3]	2,268			2,268			2,407
Fair Value	[3]	2,243			2,243			2,381
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss	[3]	26			26			23
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Amortized Cost	[3]	1,006			1,006			1,164
Commercial Mortgage Backed Securities [Member]
Available-for-sale Securities, Fair Value to Amortized Cost Basis [Abstract]
Available-for-sale Debt Securities, Amortized Cost Basis		5,014			5,014			4,668
Available-for-sale Debt Securities, Accumulated Gross Unrealized Gain, before Tax		213			213			105
Available-for-sale Debt Securities, Accumulated Gross Unrealized Loss, before Tax		32			32			56
Accumulated Other Comprehensive Income (Loss), Other than Temporary Impairment, Not Credit Loss, Net of Tax, Available-for-sale, Debt Securities	[1]	7			7			8
Available-for-sale Securities, Debt Maturities, Amortized Cost Basis, Fiscal Year Maturity [Abstract]
Total fixed maturities, AFS, amortized cost		5,014			5,014			4,668
Available-for-sale Securities, Debt Maturities, Fair Value, Fiscal Year Maturity [Abstract]
Total fixed maturities, AFS, fair value		5,195			5,195			4,717
Available-for-sale Securities, Continuous Unrealized Loss Position [Abstract]
Less Than 12 Months, Fair Value		536			536			1,681
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss		12			12			45
Available-for-sale Securities Continuous Unrealized Loss Position Twelve Months or Longer Amortized Cost		413			413			189
12 Months or More, Fair Value		393			393			178
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss		20			20			11
Amortized Cost		961			961			1,915
Fair Value		929			929			1,859
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss		32			32			56
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Amortized Cost		548			548			1,726
Corporate Debt Securities [Member]
Available-for-sale Securities, Fair Value to Amortized Cost Basis [Abstract]
Available-for-sale Debt Securities, Amortized Cost Basis		25,010			25,010			25,876
Available-for-sale Debt Securities, Accumulated Gross Unrealized Gain, before Tax		2,281			2,281			1,342
Available-for-sale Debt Securities, Accumulated Gross Unrealized Loss, before Tax		133			133			416
Accumulated Other Comprehensive Income (Loss), Other than Temporary Impairment, Not Credit Loss, Net of Tax, Available-for-sale, Debt Securities	[1]	9			9			3
Available-for-sale Securities, Debt Maturities, Amortized Cost Basis, Fiscal Year Maturity [Abstract]
Total fixed maturities, AFS, amortized cost		25,010			25,010			25,876
Available-for-sale Securities, Debt Maturities, Fair Value, Fiscal Year Maturity [Abstract]
Total fixed maturities, AFS, fair value		27,158			27,158			26,802
Available-for-sale Securities, Continuous Unrealized Loss Position [Abstract]
Less Than 12 Months, Fair Value		1,685			1,685			8,866
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss		57			57			340
Available-for-sale Securities Continuous Unrealized Loss Position Twelve Months or Longer Amortized Cost		1,008			1,008			656
12 Months or More, Fair Value		932			932			580
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss		76			76			76
Amortized Cost		2,750			2,750			9,862
Fair Value		2,617			2,617			9,446
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss		133			133			416
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Amortized Cost		1,742			1,742			9,206
Foreign Government Debt Securities [Member]
Available-for-sale Securities, Fair Value to Amortized Cost Basis [Abstract]
Available-for-sale Debt Securities, Amortized Cost Basis		1,116			1,116			1,321
Available-for-sale Debt Securities, Accumulated Gross Unrealized Gain, before Tax		78			78			34
Available-for-sale Debt Securities, Accumulated Gross Unrealized Loss, before Tax		6			6			47
Accumulated Other Comprehensive Income (Loss), Other than Temporary Impairment, Not Credit Loss, Net of Tax, Available-for-sale, Debt Securities	[1]	0			0			0
Available-for-sale Securities, Debt Maturities, Amortized Cost Basis, Fiscal Year Maturity [Abstract]
Total fixed maturities, AFS, amortized cost		1,116			1,116			1,321
Available-for-sale Securities, Debt Maturities, Fair Value, Fiscal Year Maturity [Abstract]
Total fixed maturities, AFS, fair value		1,188			1,188			1,308
Available-for-sale Securities, Continuous Unrealized Loss Position [Abstract]
Less Than 12 Months, Fair Value		55			55			646
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss		2			2			33
Available-for-sale Securities Continuous Unrealized Loss Position Twelve Months or Longer Amortized Cost		129			129			124
12 Months or More, Fair Value		125			125			110
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss		4			4			14
Amortized Cost		186			186			803
Fair Value		180			180			756
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss		6			6			47
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Amortized Cost		57			57			679
Municipal Bonds [Member]
Available-for-sale Securities, Continuous Unrealized Loss Position [Abstract]
Less Than 12 Months, Fair Value		95			95			430
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss		2			2			10
Available-for-sale Securities Continuous Unrealized Loss Position Twelve Months or Longer Amortized Cost		21			21			18
12 Months or More, Fair Value		20			20			17
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss		1			1			1
Amortized Cost		118			118			458
Fair Value		115			115			447
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss		3			3			11
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Amortized Cost		97			97			440
US States and Political Subdivisions Debt Securities [Member]
Available-for-sale Securities, Fair Value to Amortized Cost Basis [Abstract]
Available-for-sale Debt Securities, Amortized Cost Basis		11,206			11,206			11,124
Available-for-sale Debt Securities, Accumulated Gross Unrealized Gain, before Tax		1,408			1,408			1,008
Available-for-sale Debt Securities, Accumulated Gross Unrealized Loss, before Tax		3			3			11
Accumulated Other Comprehensive Income (Loss), Other than Temporary Impairment, Not Credit Loss, Net of Tax, Available-for-sale, Debt Securities	[1]	0			0			0
Available-for-sale Securities, Debt Maturities, Amortized Cost Basis, Fiscal Year Maturity [Abstract]
Total fixed maturities, AFS, amortized cost		11,206			11,206			11,124
Available-for-sale Securities, Debt Maturities, Fair Value, Fiscal Year Maturity [Abstract]
Total fixed maturities, AFS, fair value		12,611			12,611			12,121
Residential Mortgage Backed Securities [Member]
Available-for-sale Securities, Fair Value to Amortized Cost Basis [Abstract]
Available-for-sale Debt Securities, Amortized Cost Basis		4,723			4,723			3,986
Available-for-sale Debt Securities, Accumulated Gross Unrealized Gain, before Tax		123			123			82
Available-for-sale Debt Securities, Accumulated Gross Unrealized Loss, before Tax		20			20			22
Accumulated Other Comprehensive Income (Loss), Other than Temporary Impairment, Not Credit Loss, Net of Tax, Available-for-sale, Debt Securities	[1]	0			0			0
Available-for-sale Securities, Debt Maturities, Amortized Cost Basis, Fiscal Year Maturity [Abstract]
Total fixed maturities, AFS, amortized cost		4,723			4,723			3,986
Available-for-sale Securities, Debt Maturities, Fair Value, Fiscal Year Maturity [Abstract]
Total fixed maturities, AFS, fair value		4,826			4,826			4,046
Available-for-sale Securities, Continuous Unrealized Loss Position [Abstract]
Less Than 12 Months, Fair Value		583			583			1,340
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss		4			4			9
Available-for-sale Securities Continuous Unrealized Loss Position Twelve Months or Longer Amortized Cost		709			709			415
12 Months or More, Fair Value		693			693			402
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss		16			16			13
Amortized Cost		1,296			1,296			1,764
Fair Value		1,276			1,276			1,742
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss		20			20			22
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Amortized Cost		587			587			1,349
US Treasury Securities [Member]
Available-for-sale Securities, Fair Value to Amortized Cost Basis [Abstract]
Available-for-sale Debt Securities, Amortized Cost Basis		4,042			4,042			4,481
Available-for-sale Debt Securities, Accumulated Gross Unrealized Gain, before Tax		577			577			222
Available-for-sale Debt Securities, Accumulated Gross Unrealized Loss, before Tax		0			0			38
Accumulated Other Comprehensive Income (Loss), Other than Temporary Impairment, Not Credit Loss, Net of Tax, Available-for-sale, Debt Securities	[1]	0			0			0
Available-for-sale Securities, Debt Maturities, Amortized Cost Basis, Fiscal Year Maturity [Abstract]
Total fixed maturities, AFS, amortized cost		4,042			4,042			4,481
Available-for-sale Securities, Debt Maturities, Fair Value, Fiscal Year Maturity [Abstract]
Total fixed maturities, AFS, fair value		4,619			4,619			4,665
Available-for-sale Securities, Continuous Unrealized Loss Position [Abstract]
Less Than 12 Months, Fair Value		2			2			2,394
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss		0			0			38
Available-for-sale Securities Continuous Unrealized Loss Position Twelve Months or Longer Amortized Cost		0			0			8
12 Months or More, Fair Value		0			0			8
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss		0			0			0
Amortized Cost		2			2			2,440
Fair Value		2			2			2,402
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss		0			0			38
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Amortized Cost		2			2			2,432
Debt Securities [Member]
Available-for-sale Securities, Fair Value to Amortized Cost Basis [Abstract]
Accumulated Other Comprehensive Income (Loss), Other than Temporary Impairment, Not Credit Loss, Net of Tax, Available-for-sale, Debt Securities	[1]	16			16			11
Available-for-sale Securities, Continuous Unrealized Loss Position [Abstract]
Less Than 12 Months, Fair Value		4,708			4,708			18,120
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss		90			90			495
Available-for-sale Securities Continuous Unrealized Loss Position Twelve Months or Longer Amortized Cost		3,969			3,969			3,010
12 Months or More, Fair Value		3,798			3,798			2,844
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss		171			171			163
Amortized Cost		8,766			8,766			21,625
Fair Value		8,506			8,506			20,964
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss		261			261			658
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Amortized Cost		4,797			4,797			18,615
Available-for-sale Securities [Member]
Available-for-sale Securities, Fair Value to Amortized Cost Basis [Abstract]
Available-for-sale Securities		62,068			62,068
Accumulated Other Comprehensive Income (Loss), Other than Temporary Impairment, Not Credit Loss, Net of Tax, Available-for-sale, Debt Securities	[1]	16			16			11
Equity Securities [Member]
Available-for-sale Securities, Fair Value to Amortized Cost Basis [Abstract]
Available-for-sale Equity Securities, Amortized Cost Basis		772	[4]		772	[4]		842
Available-for-sale Equity Securities, Accumulated Gross Unrealized Gain, before Tax	[4]	79			79			38
Available-for-sale Equity Securities, Accumulated Gross Unrealized Loss, before Tax	[4]	24			24			41
Available-for-sale Securities, Equity Securities	[4]	827			827			839
Accumulated Other Comprehensive Income (Loss), Other than Temporary Impairment, Not Credit Loss, Net of Tax, Available-for-sale, Debt Securities	[1],[4]	0			0			0
Available-for-sale Securities, Continuous Unrealized Loss Position [Abstract]
Less Than 12 Months, Fair Value	[5]	184			184			449
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	[5]	17			17			31
Available-for-sale Securities Continuous Unrealized Loss Position Twelve Months or Longer Amortized Cost	[5]	71			71			62
12 Months or More, Fair Value	[5]	64			64			52
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	[5]	7			7			10
Amortized Cost	[5]	272			272			542
Fair Value	[5]	248			248			501
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss	[5]	24			24			41
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Amortized Cost	[5]	201			201			480
Fixed maturities available-for-sale, excluding mortgage-backed and asset-backed securities [Member]
Available-for-sale Securities, Fair Value to Amortized Cost Basis [Abstract]
Available-for-sale Debt Securities, Amortized Cost Basis		41,374			41,374			42,802
Available-for-sale Securities, Debt Maturities, Amortized Cost Basis, Fiscal Year Maturity [Abstract]
Total fixed maturities, AFS, amortized cost		41,374			41,374			42,802
Available-for-sale Securities, Debt Maturities, Fair Value, Fiscal Year Maturity [Abstract]
Total fixed maturities, AFS, fair value		45,576			45,576			44,896
Equity Securities [Member]
Available-for-sale Securities, Fair Value to Amortized Cost Basis [Abstract]
Available-for-sale Equity Securities, Amortized Cost Basis								293
Available-for-sale Securities, Equity Securities		0			0			282
Accumulated Net Investment Gain (Loss) Attributable to Parent [Member] | Reclassification out of Accumulated Other Comprehensive Income [Member]
Available-for-sale Securities, Continuous Unrealized Loss Position [Abstract]
Gain (Loss) on Investments, Excluding Other than Temporary Impairments		92		6	51		$ 43
Equity Securities [Member]
Available-for-sale Securities, Continuous Unrealized Loss Position [Abstract]
Assets, Fair Value Disclosure		0			0			282
JAPAN | Three Win Related Foreign Currency Swaps [Member]
Schedule of Available-for-sale Securities [Line Items]
Change in Unrealized Gain (Loss) on Hedged Item in Foreign Currency Fair Value Hedge					$ (108)
JAPAN | Fair Value Hedging [Member] | Three Win Related Foreign Currency Swaps [Member]
Schedule of Available-for-sale Securities [Line Items]
Change in Unrealized Gain (Loss) on Hedged Item in Foreign Currency Fair Value Hedge		$ (64)		$ 16				$ 16

[1] Represents the amount of cumulative non-credit OTTI losses recognized in OCI on securities that also had credit impairments. These losses are included in gross unrealized losses as of June 30, 2016, and December 31, 2015.

[2] Gross unrealized gains (losses) exclude the fair value of bifurcated embedded derivatives within certain securities. Subsequent changes in value are recorded in net realized capital gains (losses).

[3] 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).

[4] Excluded equity securities, FVO, with a cost and fair value of $293 and $282 as of December 31, 2015. The Company held no equity securities, FVO as of June 30, 2016.

[5] As of June 30, 2016, and December 31, 2015, excludes equity securities, FVO which are included in equity securities, AFS on the Condensed Consolidated Balance Sheets.