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	Mar. 31, 2023 USD ($) securities	Dec. 31, 2022 USD ($) securities
Debt Securities, Available-for-sale [Line Items]
Number of securities, less than 12 months | securities	3,636	7,781
Estimated fair value, less than 12 months	$ 7,474	$ 16,035
Gross unrealized loss, less than 12 months	$ (251)	$ (1,071)
Number of securities, 12 months or greater | securities	7,039	4,060
Estimated fair value, 12 months or greater	$ 14,151	$ 7,537
Gross unrealized loss, 12 months or greater	$ (1,671)	$ (1,307)
United States Government Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Number of securities, less than 12 months | securities	39	61
Estimated fair value, less than 12 months	$ 490	$ 701
Gross unrealized loss, less than 12 months	$ (13)	$ (40)
Number of securities, 12 months or greater | securities	47	38
Estimated fair value, 12 months or greater	$ 393	$ 442
Gross unrealized loss, 12 months or greater	$ (53)	$ (63)
Government Sponsored Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Number of securities, less than 12 months | securities	15	39
Estimated fair value, less than 12 months	$ 38	$ 73
Gross unrealized loss, less than 12 months	$ (1)	$ (4)
Number of securities, 12 months or greater | securities	30	6
Estimated fair value, 12 months or greater	$ 19	$ 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	80	150
Estimated fair value, less than 12 months	$ 40	$ 100
Gross unrealized loss, less than 12 months	$ (3)	$ (10)
Number of securities, 12 months or greater | securities	231	198
Estimated fair value, 12 months or greater	$ 186	$ 142
Gross unrealized loss, 12 months or greater	$ (40)	$ (36)
States, Municipalities And Political Subdivisions [Member]
Debt Securities, Available-for-sale [Line Items]
Number of securities, less than 12 months | securities	468	1,398
Estimated fair value, less than 12 months	$ 945	$ 2,615
Gross unrealized loss, less than 12 months	$ (12)	$ (147)
Number of securities, 12 months or greater | securities	967	396
Estimated fair value, 12 months or greater	$ 1,689	$ 652
Gross unrealized loss, 12 months or greater	$ (180)	$ (118)
Corporate Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Number of securities, less than 12 months | securities	1,878	3,551
Estimated fair value, less than 12 months	$ 3,636	$ 7,826
Gross unrealized loss, less than 12 months	$ (114)	$ (549)
Number of securities, 12 months or greater | securities	3,207	2,204
Estimated fair value, 12 months or greater	$ 6,687	$ 3,521
Gross unrealized loss, 12 months or greater	$ (842)	$ (669)
Residential Mortgage-Backed Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Number of securities, less than 12 months | securities	532	1,341
Estimated fair value, less than 12 months	$ 579	$ 1,435
Gross unrealized loss, less than 12 months	$ (25)	$ (121)
Number of securities, 12 months or greater | securities	1,224	496
Estimated fair value, 12 months or greater	$ 1,730	$ 982
Gross unrealized loss, 12 months or greater	$ (256)	$ (203)
Commercial Mortgage-Backed Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Number of securities, less than 12 months | securities	260	457
Estimated fair value, less than 12 months	$ 679	$ 1,082
Gross unrealized loss, less than 12 months	$ (24)	$ (76)
Number of securities, 12 months or greater | securities	558	324
Estimated fair value, 12 months or greater	$ 1,298	$ 719
Gross unrealized loss, 12 months or greater	$ (149)	$ (100)
Other Asset-Backed Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Number of securities, less than 12 months | securities	364	784
Estimated fair value, less than 12 months	$ 1,067	$ 2,203
Gross unrealized loss, less than 12 months	$ (59)	$ (124)
Number of securities, 12 months or greater | securities	775	398
Estimated fair value, 12 months or greater	$ 2,149	$ 1,074
Gross unrealized loss, 12 months or greater	$ (149)	$ (117)