Fair Value Measurements - Information about Valuation Inputs for Variable Interest Entity Assets and Liabilities Classified as Level 3 (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Fair Value Inputs, Liabilities, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Estimated Future Premium Payments Weighted Average Discounted Rate	3.00%	2.20%
Asset-backed Securities [Member]
Fair Value Inputs, Liabilities, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Fair Value Inputs Coupon Rate	5.98%	5.97%
Fair Value Inputs Maturity	13 years 5 months 15 days	14 years 1 month 20 days
Fair Value Inputs Yield	12.60%	10.20%
Variable Interest Entity [Member]
Fair Value Inputs, Liabilities, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Fair Value Asset Or Liability Measured On Recurring Basis Change In Unrealized Gains Losses Still Held			$ 281
Estimated Future Premium Payments Weighted Average Discounted Rate	6.80%	3.00%
Estimated Future Premium Payments Minimum Discounted Rate	5.80%	2.20%
Estimated Future Premium Payments Maximum Discounted Rate	8.50%	4.10%