Investments (Amortized Cost And Fair Value Of Available-For-Sale and Held-To-Maturity Investment Portfolios) (Detail) - Fixed Maturities [Member] - USD ($) $ in Millions	Dec. 31, 2021	Dec. 31, 2020
Available For Sale Securities [Abstract]
Total available-for-sale, amortized cost	$ 2,316	$ 2,360
Allowance for Credit Losess	0	0
Gross unrealized gains	150	184
Gross unrealized losses	(9)	(5)
Total available-for-sale, fair value	2,457	2,539
U S Treasury And Government [Member]
Available For Sale Securities [Abstract]
Total available-for-sale, amortized cost	782	775
Allowance for Credit Losess	0	0
Gross unrealized gains	54	75
Gross unrealized losses	(2)	(1)
Total available-for-sale, fair value	834	849
US States And Political Subdivisions [Member]
Available For Sale Securities [Abstract]
Total available-for-sale, amortized cost	140	162
Allowance for Credit Losess	0	0
Gross unrealized gains	27	32
Gross unrealized losses	0	0
Total available-for-sale, fair value	167	194
Foreign Governments [Member]
Available For Sale Securities [Abstract]
Total available-for-sale, amortized cost	13	11
Allowance for Credit Losess	0	0
Gross unrealized gains	1	1
Gross unrealized losses	0	0
Total available-for-sale, fair value	14	12
Corporate Obligations [Member]
Available For Sale Securities [Abstract]
Total available-for-sale, amortized cost	905	827
Allowance for Credit Losess	0	0
Gross unrealized gains	53	64
Gross unrealized losses	(5)	(1)
Total available-for-sale, fair value	953	890
Residential Mortgage-Backed Agency [Member]
Available For Sale Securities [Abstract]
Total available-for-sale, amortized cost	190	305
Allowance for Credit Losess	0	0
Gross unrealized gains	3	8
Gross unrealized losses	(1)	(1)
Total available-for-sale, fair value	192	312
Residential Mortgage-Backed Non-Agency [Member]
Available For Sale Securities [Abstract]
Total available-for-sale, amortized cost	80	22
Allowance for Credit Losess	0	0
Gross unrealized gains	12	3
Gross unrealized losses	0	0
Total available-for-sale, fair value	92	25
Commercial Mortgage-Backed [Member]
Available For Sale Securities [Abstract]
Total available-for-sale, amortized cost	10	17
Allowance for Credit Losess	0	0
Gross unrealized gains	0	1
Gross unrealized losses	0	0
Total available-for-sale, fair value	10	18
Collateralized Debt Obligations [Member]
Available For Sale Securities [Abstract]
Total available-for-sale, amortized cost	101	120
Allowance for Credit Losess	0	0
Gross unrealized gains	0	0
Gross unrealized losses	0	(2)
Total available-for-sale, fair value	101	118
Other Asset-Backed [Member]
Available For Sale Securities [Abstract]
Total available-for-sale, amortized cost	95	121
Allowance for Credit Losess	0	0
Gross unrealized gains	0	0
Gross unrealized losses	(1)	0
Total available-for-sale, fair value	$ 94	$ 121

Amount, before tax, of unrealized gain in accumulated other comprehensive income (AOCI) on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

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Amount, before tax, of unrealized loss in accumulated other comprehensive income (AOCI) on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

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Amount of allowance for credit loss on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

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Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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Amortized cost, after allowance for credit loss, of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

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