Fair Value Measurements - Fair Value of Life Policy Loans, Deferred Annuities, and Structured Settlements (Detail) - USD ($) $ in Millions	Mar. 31, 2022	Dec. 31, 2021
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Fair value of life policy loans	$ 40	$ 44
Liabilities Related to Investment Contracts, Fair Value Disclosure	881	979
Quoted prices in active markets for identical assets (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Fair value of life policy loans	0	0
Liabilities Related to Investment Contracts, Fair Value Disclosure	0	0
Significant other observable inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Fair value of life policy loans	0	0
Liabilities Related to Investment Contracts, Fair Value Disclosure	177	201
Significant unobservable inputs (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Fair value of life policy loans	40	44
Liabilities Related to Investment Contracts, Fair Value Disclosure	704	778
Deferred annuities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Liabilities Related to Investment Contracts, Fair Value Disclosure	704	778
Deferred annuities | Quoted prices in active markets for identical assets (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Liabilities Related to Investment Contracts, Fair Value Disclosure	0	0
Deferred annuities | Significant other observable inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Liabilities Related to Investment Contracts, Fair Value Disclosure	0	0
Deferred annuities | Significant unobservable inputs (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Liabilities Related to Investment Contracts, Fair Value Disclosure	704	778
Structured settlements
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Liabilities Related to Investment Contracts, Fair Value Disclosure	177	201
Structured settlements | Quoted prices in active markets for identical assets (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Liabilities Related to Investment Contracts, Fair Value Disclosure	0	0
Structured settlements | Significant other observable inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Liabilities Related to Investment Contracts, Fair Value Disclosure	177	201
Structured settlements | Significant unobservable inputs (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Liabilities Related to Investment Contracts, Fair Value Disclosure	$ 0	$ 0