Investments (Gross Unrealized Losses Related To Available-For-Sale And Held-To-Maturity Investments) (Detail) - Fixed Maturities [Member] - USD ($) $ in Millions	Jun. 30, 2019	Dec. 31, 2018
Available For Sale Securities [Abstract]
Less than 12 months, fair value	$ 296	$ 1,476
Less than 12 months, unrealized losses	(2)	(47)
12 months or longer, fair value	579	944
12 months or longer, unrealized losses	(45)	(120)
Total available-for-sale, fair value	875	2,420
Total available-for-sale, unrealized losses	(47)	(167)
U S Treasury And Government [Member]
Available For Sale Securities [Abstract]
Less than 12 months, fair value	118	231
Less than 12 months, unrealized losses	0	(1)
12 months or longer, fair value	153	278
12 months or longer, unrealized losses	(2)	(9)
Total available-for-sale, fair value	271	509
Total available-for-sale, unrealized losses	(2)	(10)
US States And Political Subdivisions [Member]
Available For Sale Securities [Abstract]
Less than 12 months, fair value	0	60
Less than 12 months, unrealized losses	0	(1)
12 months or longer, fair value	57	135
12 months or longer, unrealized losses	(1)	(10)
Total available-for-sale, fair value	57	195
Total available-for-sale, unrealized losses	(1)	(11)
Foreign Government Debt [Member]
Available For Sale Securities [Abstract]
Less than 12 months, fair value	3	5
Less than 12 months, unrealized losses	0	0
12 months or longer, fair value	0	2
12 months or longer, unrealized losses	0	0
Total available-for-sale, fair value	3	7
Total available-for-sale, unrealized losses	0	0
Corporate Obligations [Member]
Available For Sale Securities [Abstract]
Less than 12 months, fair value	52	900
Less than 12 months, unrealized losses	(1)	(41)
12 months or longer, fair value	212	335
12 months or longer, unrealized losses	(36)	(90)
Total available-for-sale, fair value	264	1,235
Total available-for-sale, unrealized losses	(37)	(131)
Residential Mortgage Backed Agency [Member]
Available For Sale Securities [Abstract]
Less than 12 months, fair value	26	29
Less than 12 months, unrealized losses	0	(1)
12 months or longer, fair value	94	118
12 months or longer, unrealized losses	(1)	(4)
Total available-for-sale, fair value	120	147
Total available-for-sale, unrealized losses	(1)	(5)
Residential Mortgage Backed Non Agency [Member]
Available For Sale Securities [Abstract]
Less than 12 months, fair value	0	2
Less than 12 months, unrealized losses	0	0
12 months or longer, fair value	12	13
12 months or longer, unrealized losses	(4)	(4)
Total available-for-sale, fair value	12	15
Total available-for-sale, unrealized losses	(4)	(4)
Commercial Mortgage Backed Securities [Member]
Available For Sale Securities [Abstract]
Less than 12 months, fair value	1	24
Less than 12 months, unrealized losses	0	0
12 months or longer, fair value	0	21
12 months or longer, unrealized losses	0	(2)
Total available-for-sale, fair value	1	45
Total available-for-sale, unrealized losses	0	(2)
Collateralized Debt Obligations [Member]
Available For Sale Securities [Abstract]
Less than 12 months, fair value	68	98
Less than 12 months, unrealized losses	(1)	(3)
12 months or longer, fair value	22	7
12 months or longer, unrealized losses	(1)	0
Total available-for-sale, fair value	90	105
Total available-for-sale, unrealized losses	(2)	(3)
Other Asset Backed [Member]
Available For Sale Securities [Abstract]
Less than 12 months, fair value	28	127
Less than 12 months, unrealized losses	0	0
12 months or longer, fair value	29	35
12 months or longer, unrealized losses	0	(1)
Total available-for-sale, fair value	57	162
Total available-for-sale, unrealized losses	$ 0	$ (1)

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- Definition

Amount of accumulated unrealized loss on investments in debt and equity securities classified as available-for-sale that have been in a continuous loss position for twelve months or longer.

+ References

No definition available.

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- Definition

Amount of accumulated unrealized loss on investments in debt and equity securities classified as available-for-sale in a continuous loss position.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 7
-URI http://asc.fasb.org/extlink&oid=82897076&loc=d3e27337-111563

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This item represents the aggregate fair value of investments in debt and equity securities in an unrealized loss position which are categorized neither as held-to-maturity nor trading securities.

+ References

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Amount of accumulated unrealized loss on investments in debt and equity securities classified as available-for-sale that have been in a continuous loss position for less than twelve months.

+ References

No definition available.

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+ References

No definition available.

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