Schedule of Positions in Derivative Instruments (Detail) - USD ($) $ in Millions		Sep. 30, 2019	Dec. 31, 2018
Derivative [Line Items]
Derivative assets, fair value		$ 512	$ 117
Derivative liabilities, fair value		847	847
Policyholder account balances
Derivative [Line Items]
Derivative liabilities, fair value		843	738
Other liabilities
Derivative [Line Items]
Derivative liabilities, fair value		4	109
Other invested assets
Derivative [Line Items]
Derivative assets, fair value		487	97
Interest rate swaps | Other liabilities
Derivative [Line Items]
Derivative liabilities, fair value			102
Interest rate swaps | Other invested assets
Derivative [Line Items]
Derivative assets, fair value		402	42
Foreign currency swaps | Other invested assets
Derivative [Line Items]
Derivative assets, fair value		10	6
Equity index options | Other invested assets
Derivative [Line Items]
Derivative assets, fair value		62	39
Other foreign currency contracts | Other liabilities
Derivative [Line Items]
Derivative liabilities, fair value		4	7
Other foreign currency contracts | Other invested assets
Derivative [Line Items]
Derivative assets, fair value		13	10
GMWB embedded derivatives | Policyholder account balances
Derivative [Line Items]
Derivative liabilities, fair value	[1]	381	337
GMWB embedded derivatives | Reinsurance recoverable
Derivative [Line Items]
Derivative assets, fair value	[2]	25	20
Fixed index annuity embedded derivatives | Policyholder account balances
Derivative [Line Items]
Derivative liabilities, fair value		444	389
Indexed universal life embedded derivatives | Policyholder account balances
Derivative [Line Items]
Derivative liabilities, fair value		18	12
Designated As Hedging Instrument
Derivative [Line Items]
Derivative assets, fair value		412	48
Derivative liabilities, fair value		0	102
Designated As Hedging Instrument | Cash Flow Hedges
Derivative [Line Items]
Derivative assets, fair value		412	48
Derivative liabilities, fair value		0	102
Designated As Hedging Instrument | Cash Flow Hedges | Interest rate swaps | Other liabilities
Derivative [Line Items]
Derivative liabilities, fair value		0	102
Designated As Hedging Instrument | Cash Flow Hedges | Interest rate swaps | Other invested assets
Derivative [Line Items]
Derivative assets, fair value		402	42
Designated As Hedging Instrument | Cash Flow Hedges | Foreign currency swaps | Other liabilities
Derivative [Line Items]
Derivative liabilities, fair value		0	0
Designated As Hedging Instrument | Cash Flow Hedges | Foreign currency swaps | Other invested assets
Derivative [Line Items]
Derivative assets, fair value		10	6
Derivatives not designated as hedges
Derivative [Line Items]
Derivative assets, fair value		100	69
Derivative liabilities, fair value		847	745
Derivatives not designated as hedges | Equity index options | Other liabilities
Derivative [Line Items]
Derivative liabilities, fair value		0	0
Derivatives not designated as hedges | Equity index options | Other invested assets
Derivative [Line Items]
Derivative assets, fair value		62	39
Derivatives not designated as hedges | Financial futures | Other liabilities
Derivative [Line Items]
Derivative liabilities, fair value		0	0
Derivatives not designated as hedges | Financial futures | Other invested assets
Derivative [Line Items]
Derivative assets, fair value		0	0
Derivatives not designated as hedges | Other foreign currency contracts | Other liabilities
Derivative [Line Items]
Derivative liabilities, fair value		4	7
Derivatives not designated as hedges | Other foreign currency contracts | Other invested assets
Derivative [Line Items]
Derivative assets, fair value		13	10
Derivatives not designated as hedges | GMWB embedded derivatives | Policyholder account balances
Derivative [Line Items]
Derivative liabilities, fair value	[3]	381	337
Derivatives not designated as hedges | GMWB embedded derivatives | Reinsurance recoverable
Derivative [Line Items]
Derivative assets, fair value	[4]	25	20
Derivatives not designated as hedges | Fixed index annuity embedded derivatives | Policyholder account balances
Derivative [Line Items]
Derivative liabilities, fair value	[5]	444	389
Derivatives not designated as hedges | Fixed index annuity embedded derivatives | Other assets
Derivative [Line Items]
Derivative assets, fair value		0	0
Derivatives not designated as hedges | Indexed universal life embedded derivatives | Policyholder account balances
Derivative [Line Items]
Derivative liabilities, fair value	[6]	18	12
Derivatives not designated as hedges | Indexed universal life embedded derivatives | Reinsurance recoverable
Derivative [Line Items]
Derivative assets, fair value		$ 0	$ 0

[1] Represents embedded derivatives associated with our GMWB liabilities, excluding the impact of reinsurance.

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

[3] Represents the embedded derivatives associated with our GMWB liabilities, excluding the impact of reinsurance.

[4] Represents embedded derivatives associated with the reinsured portion of our guaranteed minimum withdrawal benefits (“GMWB”) liabilities.

[5] Represents the embedded derivatives associated with our fixed index annuity liabilities.

[6] Represents the embedded derivatives associated with our indexed universal life liabilities.