Assets by Class of Instrument that are Measured at Fair Value on Recurring Basis (Detail) - USD ($) $ in Millions		Dec. 31, 2019	Dec. 31, 2018
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale debt securities		$ 60,339	$ 55,589
Available-for-sale equity securities		239	275
Derivative assets, fair value		310	117
Total other invested assets		1,632	1,072
Separate account assets		6,108	5,859
Total assets		67,761	62,455
Net Asset Value
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale debt securities	[1]	0	0
Available-for-sale equity securities	[1]	0	0
Separate account assets	[1]	0	0
Total assets	[1]	503	318
Other invested assets
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets, fair value		290	97
Securities lending collateral		51	102
Short-term investments		211	195
Limited partnerships		503	318
Total other invested assets		1,055	712
Other invested assets | Net Asset Value
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets, fair value	[1]	0	0
Securities lending collateral	[1]	0	0
Short-term investments	[1]	0	0
Limited partnerships	[1]	503	318
Total other invested assets	[1]	503	318
Interest rate swaps | Other invested assets
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets, fair value		197	42
Interest rate swaps | Other invested assets | Net Asset Value
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets, fair value	[1]	0	0
Foreign currency swaps | Other invested assets
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets, fair value		4	6
Foreign currency swaps | Other invested assets | Net Asset Value
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets, fair value	[1]	0	0
Equity index options | Other invested assets
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets, fair value		81	39
Equity index options | Other invested assets | Net Asset Value
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets, fair value	[1]	0	0
Other foreign currency contracts | Other invested assets
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets, fair value		8	10
Other foreign currency contracts | Other invested assets | Net Asset Value
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets, fair value	[1]	0	0
GMWB embedded derivatives | Reinsurance recoverable
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets, fair value	[2]	20	20
GMWB embedded derivatives | Reinsurance recoverable | Net Asset Value
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets, fair value	[2]	0	0	[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		5,025	4,631
Fixed maturity securities | U.S. government, agencies and government-sponsored enterprises | Net Asset Value
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale debt securities	[1]	0	0
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		2,747	2,552
Fixed maturity securities | State and Political Subdivisions | Net Asset Value
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale debt securities	[1]	0	0
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		1,350	1,268
Fixed maturity securities | Non-U.S. government | Net Asset Value
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale debt securities	[1]	0	0
Fixed maturity securities | U.S. corporate
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale debt securities		32,111	28,698
Fixed maturity securities | U.S. corporate | Net Asset Value
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale debt securities	[1]	0	0
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		4,997	4,675
Fixed maturity securities | U.S. corporate | Utilities | Net Asset Value
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale debt securities	[1]	0	0
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		2,699	2,412
Fixed maturity securities | U.S. corporate | Energy | Net Asset Value
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale debt securities	[1]	0	0
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		7,774	6,808
Fixed maturity securities | U.S. corporate | Finance and insurance | Net Asset Value
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale debt securities	[1]	0	0
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		5,701	5,036
Fixed maturity securities | U.S. corporate | Consumer-non-cyclical | Net Asset Value
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale debt securities	[1]	0	0
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		3,245	2,841
Fixed maturity securities | U.S. corporate | Technology and communications | Net Asset Value
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale debt securities	[1]	0	0
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		1,396	1,221
Fixed maturity securities | U.S. corporate | Industrial | Net Asset Value
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale debt securities	[1]	0	0
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		2,711	2,391
Fixed maturity securities | U.S. corporate | Capital goods | Net Asset Value
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale debt securities	[1]	0	0
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		1,760	1,597
Fixed maturity securities | U.S. corporate | Consumer-cyclical | Net Asset Value
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale debt securities	[1]	0	0
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		1,506	1,320
Fixed maturity securities | U.S. corporate | Transportation | Net Asset Value
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale debt securities	[1]	0	0
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		322	397
Fixed maturity securities | U.S. corporate | Other | Net Asset Value
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale debt securities	[1]	0	0
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		10,525	9,770
Fixed maturity securities | Non-U.S. corporate | Net Asset Value
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale debt securities	[1]	0	0
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		829	821
Fixed maturity securities | Non-U.S. corporate | Utilities | Net Asset Value
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale debt securities	[1]	0	0
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		1,319	1,221
Fixed maturity securities | Non-U.S. corporate | Energy | Net Asset Value
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale debt securities	[1]	0	0
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		2,319	2,106
Fixed maturity securities | Non-U.S. corporate | Finance and insurance | Net Asset Value
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale debt securities	[1]	0	0
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		684	690
Fixed maturity securities | Non-U.S. corporate | Consumer-non-cyclical | Net Asset Value
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale debt securities	[1]	0	0
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		1,138	1,040
Fixed maturity securities | Non-U.S. corporate | Technology and communications | Net Asset Value
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale debt securities	[1]	0	0
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		988	916
Fixed maturity securities | Non-U.S. corporate | Industrial | Net Asset Value
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale debt securities	[1]	0	0
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		605	572
Fixed maturity securities | Non-U.S. corporate | Capital goods | Net Asset Value
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale debt securities	[1]	0	0
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		397	313
Fixed maturity securities | Non-U.S. corporate | Consumer-cyclical | Net Asset Value
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale debt securities	[1]	0	0
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		629	610
Fixed maturity securities | Non-U.S. corporate | Transportation | Net Asset Value
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale debt securities	[1]	0	0
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		1,617	1,481
Fixed maturity securities | Non-U.S. corporate | Other | Net Asset Value
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale debt securities	[1]	0	0
Fixed maturity securities | Residential mortgage-backed
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale debt securities		2,270	2,618
Fixed maturity securities | Residential mortgage-backed | Net Asset Value
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale debt securities	[1]	0	0
Fixed maturity securities | Commercial mortgage-backed
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale debt securities		3,026	3,016
Fixed maturity securities | Commercial mortgage-backed | Net Asset Value
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale debt securities	[1]	0	0
Fixed maturity securities | Other asset-backed
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale debt securities		3,285	3,036
Fixed maturity securities | Other asset-backed | Net Asset Value
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale debt securities	[1]	0	0
Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale debt securities		0	0
Available-for-sale equity securities		62	153
Total other invested assets		0	0
Separate account assets		6,108	5,859
Total assets		6,170	6,012
Level 1 | Other invested assets
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets, fair value		0	0
Securities lending collateral		0	0
Short-term investments		0	0
Limited partnerships		0	0
Total other invested assets		0	0
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 | 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	[2]	0	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		56,148	51,724
Available-for-sale equity securities		126	64
Total other invested assets		49	0
Separate account assets		0	0
Total assets		56,745	52,143
Level 2 | Other invested assets
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets, fair value		209	58
Securities lending collateral		51	102
Short-term investments		211	195
Limited partnerships		0	0
Total other invested assets		471	355
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		197	42
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		4	6
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 | Other foreign currency contracts | Other invested assets
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets, fair value		8	10
Level 2 | GMWB embedded derivatives | Reinsurance recoverable
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets, fair value	[2]	0	0
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		5,025	4,631
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		2,645	2,501
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		1,350	1,268
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		29,872	26,700
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		4,132	4,032
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		2,570	2,291
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		7,202	6,274
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		5,607	4,963
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		3,195	2,791
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		1,356	1,182
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		2,609	2,299
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		1,587	1,386
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		1,428	1,263
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		186	219
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		8,840	8,238
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		455	417
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		1,072	1,004
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		2,085	1,935
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		625	584
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		1,110	1,014
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		884	855
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		444	399
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		250	191
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		438	439
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		1,477	1,400
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		2,243	2,583
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		3,020	2,921
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		3,153	2,882
Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale debt securities		4,191	3,865
Available-for-sale equity securities		51	58
Total other invested assets		383	248
Separate account assets		0	0
Total assets		4,343	3,982
Level 3 | Other invested assets
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets, fair value		81	39
Securities lending collateral		0	0
Short-term investments		0	0
Limited partnerships		0	0
Total other invested assets		81	39
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		81	39
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	0
Level 3 | GMWB embedded derivatives | Reinsurance recoverable
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets, fair value	[2]	20	20
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		0	0
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		102	51
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		2,239	1,998
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		865	643
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		129	121
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		572	534
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		94	73
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		50	50
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		40	39
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		102	92
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		173	211
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		78	57
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		136	178
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		1,685	1,532
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		374	404
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		247	217
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		234	171
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		59	106
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		28	26
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		104	61
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		161	173
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		147	122
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		191	171
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		140	81
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		27	35
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		6	95
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		$ 132	$ 154

[1] Limited partnerships that are measured at fair value using the NAV per share (or its equivalent) practical expedient have not been categorized in the fair value hierarchy.

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