Change in Net Unrealized Gains (Losses) on Available-for-Sale Securities Reported in Accumulated Other Comprehensive Income (Loss) (Parenthetical) (Detail) - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Components of Net Unrealized Investment Gains Losses Included in Accumulated Other Comprehensive Income Loss [Line Items]
Reclassification adjustments to net investment (gains) losses, taxes	$ (16)	$ 14	$ 100

Amount of tax expense (benefit) of reclassification adjustment from accumulated other comprehensive income for unrealized gain (loss) realized upon the sale of available-for-sale securities.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 220
-SubTopic 10
-Section 45
-Paragraph 12
-URI https://asc.fasb.org/extlink&oid=126968391&loc=d3e640-108580

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 9
-Subparagraph (d)
-URI https://asc.fasb.org/extlink&oid=126970911&loc=d3e27357-111563

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Period Type:	duration