Net Investment Income (Detail) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Net Investment Income [Line Items]
Gross investment income before expenses and fees	$ 809	$ 866	$ 1,593	$ 1,687
Expenses and fees	(22)	(22)	(42)	(42)
Net investment income	787	844	1,551	1,645
Fixed maturity securities—taxable
Net Investment Income [Line Items]
Gross investment income before expenses and fees	578	608	1,158	1,207
Fixed maturity securities—non-taxable
Net Investment Income [Line Items]
Gross investment income before expenses and fees	1	1	2	3
Equity Securities
Net Investment Income [Line Items]
Gross investment income before expenses and fees	2	2	4	5
Commercial mortgage loans
Net Investment Income [Line Items]
Gross investment income before expenses and fees	78	103	159	181
Policy Loans
Net Investment Income [Line Items]
Gross investment income before expenses and fees	51	40	101	90
Limited partnerships
Net Investment Income [Line Items]
Gross investment income before expenses and fees	32	54	39	85
Other invested assets
Net Investment Income [Line Items]
Gross investment income before expenses and fees	66	58	129	116
Cash, cash equivalents, restricted cash and short-term investments
Net Investment Income [Line Items]
Gross investment income before expenses and fees	$ 1	$ 0	$ 1	$ 0