Assets by Class of Instrument that are Measured at Fair Value on Recurring Basis (Detail) - USD ($) $ in Millions		Dec. 31, 2017		Dec. 31, 2016
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale debt securities		$ 62,525		$ 60,572
Restricted other invested assets related to securitization entities	[1]			312
Available-for-sale equity securities		820		632
Derivative assets, fair value		290	[2]	724
Total other invested assets		1,813		2,071
Separate account assets		7,230		7,299
Total assets		72,035		70,332
Other invested assets
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading securities				259
Derivative assets, fair value		276		708
Securities lending collateral		268		534
Short-term investments		902
Interest rate swaps | Other invested assets
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets, fair value		74		596
Foreign currency swaps | Other invested assets
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets, fair value		12		4
Equity index options | Other invested assets
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets, fair value		80		72
Equity return swaps | Other invested assets
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets, fair value				1
Other foreign currency contracts | Other invested assets
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets, fair value		110		35
GMWB embedded derivatives | Reinsurance recoverable
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets, fair value	[3]	14		16
Fair value
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total other invested assets		299		473
Fair value | Other invested assets
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total other invested assets		1,446		1,501
Fixed maturity securities | U.S. government, agencies and government-sponsored enterprises
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale debt securities		5,548		6,036
Fixed maturity securities | State and Political Subdivisions
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale debt securities		2,926		2,647
Fixed maturity securities | Non-U.S. government
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale debt securities		2,233		2,107
Fixed maturity securities | U.S. corporate
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale debt securities		28,636		26,828
Fixed maturity securities | U.S. corporate | Utilities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale debt securities		4,998		4,550
Fixed maturity securities | U.S. corporate | Energy
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale debt securities		2,458		2,300
Fixed maturity securities | U.S. corporate | Finance and insurance
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale debt securities		6,528		6,097
Fixed maturity securities | U.S. corporate | Consumer-non-cyclical
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale debt securities		4,831		4,734
Fixed maturity securities | U.S. corporate | Technology and communications
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale debt securities		2,845		2,598
Fixed maturity securities | U.S. corporate | Industrial
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale debt securities		1,346		1,223
Fixed maturity securities | U.S. corporate | Capital goods
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale debt securities		2,355		2,258
Fixed maturity securities | U.S. corporate | Consumer-cyclical
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale debt securities		1,605		1,530
Fixed maturity securities | U.S. corporate | Transportation
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale debt securities		1,291		1,190
Fixed maturity securities | U.S. corporate | Other
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale debt securities		379		348
Fixed maturity securities | Non-U.S. corporate
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale debt securities		12,611		12,295
Fixed maturity securities | Non-U.S. corporate | Utilities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale debt securities		1,017		969
Fixed maturity securities | Non-U.S. corporate | Energy
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale debt securities		1,490		1,331
Fixed maturity securities | Non-U.S. corporate | Finance and insurance
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale debt securities		2,735		2,538
Fixed maturity securities | Non-U.S. corporate | Consumer-non-cyclical
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale debt securities		712		714
Fixed maturity securities | Non-U.S. corporate | Technology and communications
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale debt securities		982		987
Fixed maturity securities | Non-U.S. corporate | Industrial
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale debt securities		1,044		958
Fixed maturity securities | Non-U.S. corporate | Capital goods
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale debt securities		645		535
Fixed maturity securities | Non-U.S. corporate | Consumer-cyclical
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale debt securities		540		442
Fixed maturity securities | Non-U.S. corporate | Transportation
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale debt securities		721		677
Fixed maturity securities | Non-U.S. corporate | Other
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale debt securities		2,725		3,144
Fixed maturity securities | Residential mortgage-backed
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale debt securities		4,057		4,379
Fixed maturity securities | Commercial mortgage-backed
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale debt securities		3,446		3,129
Fixed maturity securities | Other asset-backed
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale debt securities		3,068		3,151
Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale debt securities		0		0
Restricted other invested assets related to securitization entities	[1]			0
Available-for-sale equity securities		696		551
Total other invested assets		0		0
Separate account assets		7,230		7,299
Total assets		8,033		7,850
Level 1 | Other invested assets
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading securities				0
Derivative assets, fair value		0		0
Securities lending collateral		0		0
Short-term investments		107
Level 1 | Interest rate swaps | Other invested assets
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets, fair value		0		0
Level 1 | Foreign currency swaps | Other invested assets
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets, fair value		0		0
Level 1 | Equity index options | Other invested assets
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets, fair value		0		0
Level 1 | Equity return swaps | Other invested assets
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets, fair value				0
Level 1 | Other foreign currency contracts | Other invested assets
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets, fair value		0		0
Level 1 | GMWB embedded derivatives | Reinsurance recoverable
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets, fair value	[3]	0		0
Level 1 | Fair value | Other invested assets
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total other invested assets		107		0
Level 1 | Fixed maturity securities | U.S. government, agencies and government-sponsored enterprises
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale debt securities		0		0
Level 1 | Fixed maturity securities | State and Political Subdivisions
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale debt securities		0		0
Level 1 | Fixed maturity securities | Non-U.S. government
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale debt securities		0		0
Level 1 | Fixed maturity securities | U.S. corporate
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale debt securities		0		0
Level 1 | Fixed maturity securities | U.S. corporate | Utilities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale debt securities		0		0
Level 1 | Fixed maturity securities | U.S. corporate | Energy
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale debt securities		0		0
Level 1 | Fixed maturity securities | U.S. corporate | Finance and insurance
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale debt securities		0		0
Level 1 | Fixed maturity securities | U.S. corporate | Consumer-non-cyclical
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale debt securities		0		0
Level 1 | Fixed maturity securities | U.S. corporate | Technology and communications
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale debt securities		0		0
Level 1 | Fixed maturity securities | U.S. corporate | Industrial
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale debt securities		0		0
Level 1 | Fixed maturity securities | U.S. corporate | Capital goods
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale debt securities		0		0
Level 1 | Fixed maturity securities | U.S. corporate | Consumer-cyclical
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale debt securities		0		0
Level 1 | Fixed maturity securities | U.S. corporate | Transportation
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale debt securities		0		0
Level 1 | Fixed maturity securities | U.S. corporate | Other
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale debt securities		0		0
Level 1 | Fixed maturity securities | Non-U.S. corporate
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale debt securities		0		0
Level 1 | Fixed maturity securities | Non-U.S. corporate | Utilities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale debt securities		0		0
Level 1 | Fixed maturity securities | Non-U.S. corporate | Energy
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale debt securities		0		0
Level 1 | Fixed maturity securities | Non-U.S. corporate | Finance and insurance
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale debt securities		0		0
Level 1 | Fixed maturity securities | Non-U.S. corporate | Consumer-non-cyclical
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale debt securities		0		0
Level 1 | Fixed maturity securities | Non-U.S. corporate | Technology and communications
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale debt securities		0		0
Level 1 | Fixed maturity securities | Non-U.S. corporate | Industrial
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale debt securities		0		0
Level 1 | Fixed maturity securities | Non-U.S. corporate | Capital goods
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale debt securities		0		0
Level 1 | Fixed maturity securities | Non-U.S. corporate | Consumer-cyclical
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale debt securities		0		0
Level 1 | Fixed maturity securities | Non-U.S. corporate | Transportation
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale debt securities		0		0
Level 1 | Fixed maturity securities | Non-U.S. corporate | Other
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale debt securities		0		0
Level 1 | Fixed maturity securities | Residential mortgage-backed
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale debt securities		0		0
Level 1 | Fixed maturity securities | Commercial mortgage-backed
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale debt securities		0		0
Level 1 | Fixed maturity securities | Other asset-backed
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale debt securities		0		0
Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale debt securities		58,575		56,271
Restricted other invested assets related to securitization entities	[1]			181
Available-for-sale equity securities		80		34
Total other invested assets		0		352
Separate account assets		0		0
Total assets		59,914		57,912
Level 2 | Other invested assets
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading securities				259
Derivative assets, fair value		196		633
Securities lending collateral		268		534
Short-term investments		795
Level 2 | Interest rate swaps | Other invested assets
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets, fair value		74		596
Level 2 | Foreign currency swaps | Other invested assets
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets, fair value		12		4
Level 2 | Equity index options | Other invested assets
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets, fair value		0		0
Level 2 | Equity return swaps | Other invested assets
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets, fair value				1
Level 2 | Other foreign currency contracts | Other invested assets
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets, fair value		110		32
Level 2 | GMWB embedded derivatives | Reinsurance recoverable
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets, fair value	[3]	0		0
Level 2 | Fair value | Other invested assets
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total other invested assets		1,259		1,426
Level 2 | Fixed maturity securities | U.S. government, agencies and government-sponsored enterprises
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale debt securities		5,547		6,034
Level 2 | Fixed maturity securities | State and Political Subdivisions
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale debt securities		2,889		2,610
Level 2 | Fixed maturity securities | Non-U.S. government
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale debt securities		2,233		2,107
Level 2 | Fixed maturity securities | U.S. corporate
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale debt securities		26,484		24,341
Level 2 | Fixed maturity securities | U.S. corporate | Utilities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale debt securities		4,424		3,974
Level 2 | Fixed maturity securities | U.S. corporate | Energy
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale debt securities		2,311		2,090
Level 2 | Fixed maturity securities | U.S. corporate | Finance and insurance
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale debt securities		5,902		5,311
Level 2 | Fixed maturity securities | U.S. corporate | Consumer-non-cyclical
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale debt securities		4,750		4,613
Level 2 | Fixed maturity securities | U.S. corporate | Technology and communications
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale debt securities		2,772		2,544
Level 2 | Fixed maturity securities | U.S. corporate | Industrial
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale debt securities		1,307		1,175
Level 2 | Fixed maturity securities | U.S. corporate | Capital goods
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale debt securities		2,234		2,106
Level 2 | Fixed maturity securities | U.S. corporate | Consumer-cyclical
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale debt securities		1,343		1,272
Level 2 | Fixed maturity securities | U.S. corporate | Transportation
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale debt securities		1,231		1,051
Level 2 | Fixed maturity securities | U.S. corporate | Other
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale debt securities		210		205
Level 2 | Fixed maturity securities | Non-U.S. corporate
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale debt securities		11,195		10,762
Level 2 | Fixed maturity securities | Non-U.S. corporate | Utilities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale debt securities		674		583
Level 2 | Fixed maturity securities | Non-U.S. corporate | Energy
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale debt securities		1,314		1,125
Level 2 | Fixed maturity securities | Non-U.S. corporate | Finance and insurance
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale debt securities		2,574		2,356
Level 2 | Fixed maturity securities | Non-U.S. corporate | Consumer-non-cyclical
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale debt securities		588		575
Level 2 | Fixed maturity securities | Non-U.S. corporate | Technology and communications
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale debt securities		953		920
Level 2 | Fixed maturity securities | Non-U.S. corporate | Industrial
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale debt securities		928		849
Level 2 | Fixed maturity securities | Non-U.S. corporate | Capital goods
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale debt securities		454		366
Level 2 | Fixed maturity securities | Non-U.S. corporate | Consumer-cyclical
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale debt securities		486		373
Level 2 | Fixed maturity securities | Non-U.S. corporate | Transportation
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale debt securities		551		496
Level 2 | Fixed maturity securities | Non-U.S. corporate | Other
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale debt securities		2,673		3,119
Level 2 | Fixed maturity securities | Residential mortgage-backed
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale debt securities		3,980		4,336
Level 2 | Fixed maturity securities | Commercial mortgage-backed
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale debt securities		3,416		3,075
Level 2 | Fixed maturity securities | Other asset-backed
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale debt securities		2,831		3,006
Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale debt securities		3,950		4,301
Restricted other invested assets related to securitization entities	[1]			131
Available-for-sale equity securities		44		47
Total other invested assets		299		121
Separate account assets		0		0
Total assets		4,088		4,570
Level 3 | Other invested assets
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading securities				0
Derivative assets, fair value		80		75
Securities lending collateral		0		0
Short-term investments		0
Level 3 | Interest rate swaps | Other invested assets
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets, fair value		0		0
Level 3 | Foreign currency swaps | Other invested assets
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets, fair value		0		0
Level 3 | Equity index options | Other invested assets
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets, fair value		80		72
Level 3 | Equity return swaps | Other invested assets
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets, fair value				0
Level 3 | Other foreign currency contracts | Other invested assets
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets, fair value		0		3
Level 3 | GMWB embedded derivatives | Reinsurance recoverable
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets, fair value	[3]	14		16
Level 3 | Fair value | Other invested assets
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total other invested assets		80		75
Level 3 | Fixed maturity securities | U.S. government, agencies and government-sponsored enterprises
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale debt securities		1		2
Level 3 | Fixed maturity securities | State and Political Subdivisions
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale debt securities		37		37
Level 3 | Fixed maturity securities | Non-U.S. government
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale debt securities		0		0
Level 3 | Fixed maturity securities | U.S. corporate
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale debt securities		2,152		2,487
Level 3 | Fixed maturity securities | U.S. corporate | Utilities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale debt securities		574		576
Level 3 | Fixed maturity securities | U.S. corporate | Energy
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale debt securities		147		210
Level 3 | Fixed maturity securities | U.S. corporate | Finance and insurance
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale debt securities		626		786
Level 3 | Fixed maturity securities | U.S. corporate | Consumer-non-cyclical
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale debt securities		81		121
Level 3 | Fixed maturity securities | U.S. corporate | Technology and communications
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale debt securities		73		54
Level 3 | Fixed maturity securities | U.S. corporate | Industrial
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale debt securities		39		48
Level 3 | Fixed maturity securities | U.S. corporate | Capital goods
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale debt securities		121		152
Level 3 | Fixed maturity securities | U.S. corporate | Consumer-cyclical
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale debt securities		262		258
Level 3 | Fixed maturity securities | U.S. corporate | Transportation
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale debt securities		60		139
Level 3 | Fixed maturity securities | U.S. corporate | Other
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale debt securities		169		143
Level 3 | Fixed maturity securities | Non-U.S. corporate
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale debt securities		1,416		1,533
Level 3 | Fixed maturity securities | Non-U.S. corporate | Utilities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale debt securities		343		386
Level 3 | Fixed maturity securities | Non-U.S. corporate | Energy
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale debt securities		176		206
Level 3 | Fixed maturity securities | Non-U.S. corporate | Finance and insurance
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale debt securities		161		182
Level 3 | Fixed maturity securities | Non-U.S. corporate | Consumer-non-cyclical
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale debt securities		124		139
Level 3 | Fixed maturity securities | Non-U.S. corporate | Technology and communications
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale debt securities		29		67
Level 3 | Fixed maturity securities | Non-U.S. corporate | Industrial
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale debt securities		116		109
Level 3 | Fixed maturity securities | Non-U.S. corporate | Capital goods
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale debt securities		191		169
Level 3 | Fixed maturity securities | Non-U.S. corporate | Consumer-cyclical
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale debt securities		54		69
Level 3 | Fixed maturity securities | Non-U.S. corporate | Transportation
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale debt securities		170		181
Level 3 | Fixed maturity securities | Non-U.S. corporate | Other
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale debt securities		52		25
Level 3 | Fixed maturity securities | Residential mortgage-backed
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale debt securities		77		43
Level 3 | Fixed maturity securities | Commercial mortgage-backed
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale debt securities		30		54
Level 3 | Fixed maturity securities | Other asset-backed
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale debt securities		$ 237		$ 145

[1] See note 17 for additional information related to consolidated securitization entities.

[2] In the third quarter of 2017, recent central clearing parties rule changes impacted our accounting treatment for variation margin pertaining to cleared swap positions, which was previously considered cash collateral and is now treated as daily settlements of the derivative contract. The change reduced the value of our derivative assets and derivative liabilities by $473 million and $206 million, respectively, in 2017.

[3] Represents embedded derivatives associated with the reinsured portion of our GMWB liabilities.