Investments (Summary of Allowance for Credit Losses on AFS Investments) (Detail) - Accounting Standards Update 2016-13 [Member] - USD ($) $ in Millions	3 Months Ended	9 Months Ended
	Sep. 30, 2022	Sep. 30, 2022
Debt Securities, Available-for-sale, Allowance for Credit Loss [Line Items]
Beginning Balance	$ 3	$ 0
Additions not previously recorded	0	3
Additions arising from PCD Assets	0	0
Reductions from Securities Sold	0	0
Reductions – Intent to sell or MLTN	3	3
Change in Allowance Previously Recorded	0	0
Write- Offs	0	0
Recoveries	0	0
Ending balance	0	0
Corporate Obligations [Member]
Debt Securities, Available-for-sale, Allowance for Credit Loss [Line Items]
Beginning Balance	3	0
Additions not previously recorded	0	3
Additions arising from PCD Assets	0	0
Reductions from Securities Sold	0	0
Reductions – Intent to sell or MLTN	3	3
Change in Allowance Previously Recorded	0	0
Write- Offs	0	0
Recoveries	0	0
Ending balance	$ 0	$ 0