Investments (Aggregate Fair Value And Gross Unrealized Loss Of Fixed Maturity Securities In An Unrealized Loss Position) (Details) - Fixed Maturities [Member] securities in Millions, $ in Millions	Jun. 30, 2023 USD ($) securities	Dec. 31, 2022 USD ($) securities
Debt Securities, Available-for-sale [Line Items]
Number of securities, less than 12 months | securities	4,162	7,781
Estimated fair value, less than 12 months	$ 9,949	$ 16,035
Gross unrealized loss, less than 12 months	$ (310)	$ (1,071)
Number of securities, 12 months or greater | securities	7,108	4,060
Estimated fair value, 12 months or greater	$ 14,285	$ 7,537
Gross unrealized loss, 12 months or greater	$ (1,715)	$ (1,307)
United States Government Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Number of securities, less than 12 months | securities	58	61
Estimated fair value, less than 12 months	$ 1,019	$ 701
Gross unrealized loss, less than 12 months	$ (29)	$ (40)
Number of securities, 12 months or greater | securities	48	38
Estimated fair value, 12 months or greater	$ 278	$ 442
Gross unrealized loss, 12 months or greater	$ (46)	$ (63)
Government Sponsored Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Number of securities, less than 12 months | securities	18	39
Estimated fair value, less than 12 months	$ 63	$ 73
Gross unrealized loss, less than 12 months	$ (2)	$ (4)
Number of securities, 12 months or greater | securities	29	6
Estimated fair value, 12 months or greater	$ 18	$ 5
Gross unrealized loss, 12 months or greater	$ (2)	$ (1)
Foreign Government Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Number of securities, less than 12 months | securities	97	150
Estimated fair value, less than 12 months	$ 56	$ 100
Gross unrealized loss, less than 12 months	$ (2)	$ (10)
Number of securities, 12 months or greater | securities	224	198
Estimated fair value, 12 months or greater	$ 186	$ 142
Gross unrealized loss, 12 months or greater	$ (39)	$ (36)
States, Municipalities And Political Subdivisions [Member]
Debt Securities, Available-for-sale [Line Items]
Number of securities, less than 12 months | securities	702	1,398
Estimated fair value, less than 12 months	$ 1,278	$ 2,615
Gross unrealized loss, less than 12 months	$ (20)	$ (147)
Number of securities, 12 months or greater | securities	925	396
Estimated fair value, 12 months or greater	$ 1,598	$ 652
Gross unrealized loss, 12 months or greater	$ (187)	$ (118)
Corporate Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Number of securities, less than 12 months | securities	2,051	3,551
Estimated fair value, less than 12 months	$ 4,323	$ 7,826
Gross unrealized loss, less than 12 months	$ (129)	$ (549)
Number of securities, 12 months or greater | securities	3,216	2,204
Estimated fair value, 12 months or greater	$ 6,910	$ 3,521
Gross unrealized loss, 12 months or greater	$ (868)	$ (669)
Residential Mortgage-Backed Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Number of securities, less than 12 months | securities	642	1,341
Estimated fair value, less than 12 months	$ 1,251	$ 1,435
Gross unrealized loss, less than 12 months	$ (38)	$ (121)
Number of securities, 12 months or greater | securities	1,286	496
Estimated fair value, 12 months or greater	$ 1,714	$ 982
Gross unrealized loss, 12 months or greater	$ (275)	$ (203)
Commercial Mortgage-Backed Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Number of securities, less than 12 months | securities	246	457
Estimated fair value, less than 12 months	$ 701	$ 1,082
Gross unrealized loss, less than 12 months	$ (28)	$ (76)
Number of securities, 12 months or greater | securities	553	324
Estimated fair value, 12 months or greater	$ 1,316	$ 719
Gross unrealized loss, 12 months or greater	$ (152)	$ (100)
Other Asset-Backed Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Number of securities, less than 12 months | securities	348	784
Estimated fair value, less than 12 months	$ 1,258	$ 2,203
Gross unrealized loss, less than 12 months	$ (62)	$ (124)
Number of securities, 12 months or greater | securities	827	398
Estimated fair value, 12 months or greater	$ 2,265	$ 1,074
Gross unrealized loss, 12 months or greater	$ (146)	$ (117)