Fair Value of Financial Instruments - Quantitative Information of Unobservable Inputs Used for Level Three Fair Value Measurements of Financial Instruments on Recurring Basis (Detail) - USD ($) $ in Millions	Dec. 31, 2021	Dec. 31, 2020
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Assets, fair value	$ 5,600	$ 3,267
Liabilities, fair value	3,883	3,409
Discounted cash flow \| Fixed indexed annuities
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Liabilities, fair value	$ 3,883	$ 3,404
Discounted cash flow \| Fixed indexed annuities \| Minimum
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Non-performance spread	0.43%	0.74%
Market value of option	0.00%	0.00%
Mortality multiplier	100.00%	100.00%
Surrender rates	0.25%	0.25%
Partial withdrawals	2.00%	2.00%
Option cost	0.07%	0.05%
Swap rates	0.05%	0.08%
Discounted cash flow \| Fixed indexed annuities \| Maximum
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Non-performance spread	1.01%	0.74%
Market value of option	38.72%	67.65%
Mortality multiplier	100.00%	100.00%
Surrender rates	70.00%	55.00%
Partial withdrawals	23.26%	3.50%
Option cost	4.97%	16.61%
Swap rates	1.94%	1.65%
Discounted cash flow \| Fixed indexed annuities \| Weighted Average
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Non-performance spread	0.68%	0.74%
Market value of option	3.16%	2.25%
Mortality multiplier	100.00%	100.00%
Surrender rates	6.26%	5.24%
Partial withdrawals	2.72%	2.58%
Option cost	1.83%	2.25%
Swap rates	1.00%	0.87%
Discounted cash flow \| Affiliated Entity \| Minimum \| Discount rate
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Equity securities	0.1270	0.1060
Discounted cash flow \| Affiliated Entity \| Maximum \| Discount rate
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Equity securities	0.1270	0.1060
Discounted cash flow \| Affiliated Entity \| Weighted Average \| Discount rate
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Equity securities	0.1270	0.1060
Asset-backed securities \| Broker-quoted
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Assets, fair value	$ 3,844	$ 1,175
Asset-backed securities \| Broker-quoted \| Minimum
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Offered quotes	52.56%	85.00%
Asset-backed securities \| Broker-quoted \| Maximum
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Offered quotes	260.70%	126.15%
Asset-backed securities \| Broker-quoted \| Weighted Average
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Offered quotes	97.06%	103.96%
Asset-backed securities \| Third-Party Valuation
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Assets, fair value	$ 115	$ 175
Asset-backed securities \| Third-Party Valuation \| Minimum
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Offered quotes	93.02%	0.00%
Asset-backed securities \| Third-Party Valuation \| Maximum
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Offered quotes	108.45%	107.25%
Asset-backed securities \| Third-Party Valuation \| Weighted Average
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Offered quotes	104.95%	79.87%
Commercial mortgage-backed securities \| Broker-quoted
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Assets, fair value	$ 24	$ 26
Commercial mortgage-backed securities \| Broker-quoted \| Minimum
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Offered quotes	126.70%	131.59%
Commercial mortgage-backed securities \| Broker-quoted \| Maximum
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Offered quotes	126.70%	131.59%
Commercial mortgage-backed securities \| Broker-quoted \| Weighted Average
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Offered quotes	126.70%	131.59%
Commercial mortgage-backed securities \| Third-Party Valuation
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Assets, fair value	$ 11
Commercial mortgage-backed securities \| Third-Party Valuation \| Minimum
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Offered quotes	97.91%
Commercial mortgage-backed securities \| Third-Party Valuation \| Maximum
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Offered quotes	97.91%
Commercial mortgage-backed securities \| Third-Party Valuation \| Weighted Average
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Offered quotes	97.91%
Corporates \| Broker-quoted
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Assets, fair value	$ 380	$ 388
Corporates \| Broker-quoted \| Minimum
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Offered quotes	0.00%	75.20%
Corporates \| Broker-quoted \| Maximum
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Offered quotes	109.69%	114.68%
Corporates \| Broker-quoted \| Weighted Average
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Offered quotes	100.91%	103.36%
Corporates \| Third-Party Valuation
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Assets, fair value	$ 741	$ 901
Corporates \| Third-Party Valuation \| Minimum
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Offered quotes	85.71%	88.42%
Corporates \| Third-Party Valuation \| Maximum
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Offered quotes	119.57%	125.83%
Corporates \| Third-Party Valuation \| Weighted Average
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Offered quotes	107.72%	109.47%
Corporates \| Discounted cash flow
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Assets, fair value	$ 14
Corporates \| Discounted cash flow \| Minimum \| Discount rate
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Debt securities	0.4400
Corporates \| Discounted cash flow \| Maximum \| Discount rate
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Debt securities	1.0000
Corporates \| Discounted cash flow \| Weighted Average \| Discount rate
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Debt securities	0.6200
Hybrids \| Third-Party Valuation
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Assets, fair value		$ 4
Hybrids \| Third-Party Valuation \| Minimum
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Offered quotes		112.06%
Hybrids \| Third-Party Valuation \| Maximum
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Offered quotes		112.06%
Hybrids \| Third-Party Valuation \| Weighted Average
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Offered quotes		112.06%
Municipals \| Third-Party Valuation
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Assets, fair value	$ 43	$ 43
Municipals \| Third-Party Valuation \| Minimum
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Offered quotes	135.09%	133.53%
Municipals \| Third-Party Valuation \| Maximum
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Offered quotes	135.09%	133.53%
Municipals \| Third-Party Valuation \| Weighted Average
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Offered quotes	135.09%	133.53%
Residential mortgage-backed securities \| Broker-quoted
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Assets, fair value		$ 483
Residential mortgage-backed securities \| Broker-quoted \| Minimum
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Offered quotes		112.58%
Residential mortgage-backed securities \| Broker-quoted \| Maximum
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Offered quotes		112.58%
Residential mortgage-backed securities \| Broker-quoted \| Weighted Average
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Offered quotes		112.58%
Foreign Governments \| Third-Party Valuation
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Assets, fair value	$ 18	$ 17
Foreign Governments \| Third-Party Valuation \| Minimum
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Offered quotes	107.23%	107.87%
Foreign Governments \| Third-Party Valuation \| Maximum
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Offered quotes	116.44%	113.80%
Foreign Governments \| Third-Party Valuation \| Weighted Average
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Offered quotes	110.11%	109.72%
Short-term \| Broker-quoted
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Assets, fair value	$ 321
Short-term \| Broker-quoted \| Minimum
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Offered quotes	100.00%
Short-term \| Broker-quoted \| Maximum
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Offered quotes	100.00%
Short-term \| Broker-quoted \| Weighted Average
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Offered quotes	100.00%
Equity securities \| Broker-quoted
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Assets, fair value	$ 3
Equity securities \| Broker-quoted \| Minimum \| EBITDA Multiple
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Equity securities	5.9	6.6
Equity securities \| Broker-quoted \| Maximum \| EBITDA Multiple
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Equity securities	5.9	6.6
Equity securities \| Broker-quoted \| Weighted Average
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Offered quotes	623.00%
Equity securities \| Broker-quoted \| Weighted Average \| EBITDA Multiple
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Equity securities	5.9	6.6
Equity securities \| Income-Approach \| Affiliated Entity
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Assets, fair value	$ 2	$ 1
Yield	2.43%	2.61%
Equity securities \| Black Scholes model \| Affiliated Entity
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Assets, fair value	$ 2	$ 1
Equity securities \| Black Scholes model \| Affiliated Entity \| Minimum \| Risk Free Rate
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Equity securities	0.0100	0.0029
Equity securities \| Black Scholes model \| Affiliated Entity \| Minimum \| Strike Price
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Equity securities	1.50	1.50
Equity securities \| Black Scholes model \| Affiliated Entity \| Minimum \| Volatility
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Equity securities	0.8100	0.0100
Equity securities \| Black Scholes model \| Affiliated Entity \| Minimum \| Dividend Yield
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Equity securities	0.0000	0.0000
Equity securities \| Black Scholes model \| Affiliated Entity \| Maximum \| Risk Free Rate
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Equity securities	0.0100	0.0029
Equity securities \| Black Scholes model \| Affiliated Entity \| Maximum \| Strike Price
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Equity securities	1.50	1.50
Equity securities \| Black Scholes model \| Affiliated Entity \| Maximum \| Volatility
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Equity securities	0.8100	0.0100
Equity securities \| Black Scholes model \| Affiliated Entity \| Maximum \| Dividend Yield
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Equity securities	0.0000	0.0000
Equity securities \| Black Scholes model \| Affiliated Entity \| Weighted Average \| Risk Free Rate
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Equity securities	0.0100	0.0029
Equity securities \| Black Scholes model \| Affiliated Entity \| Weighted Average \| Strike Price
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Equity securities	1.50	1.50
Equity securities \| Black Scholes model \| Affiliated Entity \| Weighted Average \| Volatility
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Equity securities	0.8100	0.0100
Equity securities \| Black Scholes model \| Affiliated Entity \| Weighted Average \| Dividend Yield
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Equity securities	0.0000	0.0000
Equity securities \| Discounted cash flow \| Affiliated Entity
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Assets, fair value	$ 4	$ 3
Limited partnerships \| Third-Party Valuation
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Assets, fair value	$ 34	$ 27
Market value of fund	100.00%	100.00%
Credit Linked Note \| Broker-quoted
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Assets, fair value	$ 23	$ 23
Offered quotes	100.00%	100.00%
Investment in affiliate \| Minimum \| EBITDA Multiple
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Investment in affiliate	8
Investment in affiliate \| Maximum \| EBITDA Multiple
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Investment in affiliate	8
Investment in affiliate \| Broker-quoted
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Assets, fair value	$ 21
Future policy benefits \| Discounted cash flow \| Future policy benefits
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Liabilities, fair value	$ 0
Future policy benefits \| Discounted cash flow \| Future policy benefits \| Minimum
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Non-performance spread	0.50%	0.00%
Future policy benefits \| Discounted cash flow
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Liabilities, fair value		$ 5
Risk margin to reflect uncertainty		0.50%

Fair Value of Financial Instruments - Quantitative Information of Unobservable Inputs Used for Level Three Fair Value Measurements of Financial Instruments on Recurring Basis (Detail) - USD ($)
$ in Millions