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Investments (Amortized Cost And Fair Value Of Available-For-Sale and Held-To-Maturity Investment Portfolios) (Detail) - Fixed Maturities [Member] - USD ($) $ in Millions	Mar. 31, 2022	Dec. 31, 2021
Available For Sale Securities [Abstract]
Total available-for-sale, amortized cost	$ 3,128	$ 2,316
Allowance for Credit Losess	(3)	0
Gross unrealized gains	62	150
Gross unrealized losses	(93)	(9)
Total available-for-sale, fair value	3,094	2,457
U S Treasury And Government [Member]
Available For Sale Securities [Abstract]
Total available-for-sale, amortized cost	862	782
Allowance for Credit Losess	0	0
Gross unrealized gains	28	54
Gross unrealized losses	(15)	(2)
Total available-for-sale, fair value	875	834
US States And Political Subdivisions [Member]
Available For Sale Securities [Abstract]
Total available-for-sale, amortized cost	606	140
Allowance for Credit Losess	0	0
Gross unrealized gains	13	27
Gross unrealized losses	(20)	0
Total available-for-sale, fair value	599	167
Foreign Governments [Member]
Available For Sale Securities [Abstract]
Total available-for-sale, amortized cost	23	13
Allowance for Credit Losess	0	0
Gross unrealized gains	0	1
Gross unrealized losses	(1)	0
Total available-for-sale, fair value	22	14
Corporate Obligations [Member]
Available For Sale Securities [Abstract]
Total available-for-sale, amortized cost	1,013	905
Allowance for Credit Losess	(3)	0
Gross unrealized gains	13	53
Gross unrealized losses	(44)	(5)
Total available-for-sale, fair value	979	953
Residential Mortgage-Backed Agency [Member]
Available For Sale Securities [Abstract]
Total available-for-sale, amortized cost	186	190
Allowance for Credit Losess	0	0
Gross unrealized gains	0	3
Gross unrealized losses	(8)	(1)
Total available-for-sale, fair value	178	192
Residential Mortgage-Backed Non-Agency [Member]
Available For Sale Securities [Abstract]
Total available-for-sale, amortized cost	124	80
Allowance for Credit Losess	0	0
Gross unrealized gains	8	12
Gross unrealized losses	(1)	0
Total available-for-sale, fair value	131	92
Commercial Mortgage-Backed [Member]
Available For Sale Securities [Abstract]
Total available-for-sale, amortized cost	10	10
Allowance for Credit Losess	0	0
Gross unrealized gains	0	0
Gross unrealized losses	(1)	0
Total available-for-sale, fair value	9	10
Collateralized Debt Obligations [Member]
Available For Sale Securities [Abstract]
Total available-for-sale, amortized cost	125	101
Allowance for Credit Losess	0	0
Gross unrealized gains	0	0
Gross unrealized losses	(1)	0
Total available-for-sale, fair value	124	101
Other Asset-Backed [Member]
Available For Sale Securities [Abstract]
Total available-for-sale, amortized cost	179	95
Allowance for Credit Losess	0	0
Gross unrealized gains	0	0
Gross unrealized losses	(2)	(1)
Total available-for-sale, fair value	$ 177	$ 94

X

- Definition

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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