Employee Benefit Plans (Estimated Fair Value on a Recurring Basis) (Details) - USD ($) $ in Millions	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Pension Benefits
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	$ 7,836	$ 8,270	$ 8,294
Pension Benefits | Fixed maturity securities AFS
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	6,409	6,714
Pension Benefits | Corporate fixed maturity securities
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	3,081	3,083
Pension Benefits | U.S. government bonds
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	1,723	1,575
Pension Benefits | Foreign government
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	731	810
Pension Benefits | Federal agencies
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	179	203
Pension Benefits | Municipals
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	79	147
Pension Benefits | Short-term Investments
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	170	197
Pension Benefits | Other (1)
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	446	699
Pension Benefits | Equity Securities
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	695	610
Pension Benefits | Other invested assets
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	727	869
Pension Benefits | Derivative assets
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	5	77
Pension Benefits | Level 1
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	2,499	2,213
Pension Benefits | Level 1 | Fixed maturity securities AFS
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	1,964	1,726
Pension Benefits | Level 1 | Corporate fixed maturity securities
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Pension Benefits | Level 1 | U.S. government bonds
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	1,693	1,537
Pension Benefits | Level 1 | Foreign government
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Pension Benefits | Level 1 | Federal agencies
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	96	62
Pension Benefits | Level 1 | Municipals
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Pension Benefits | Level 1 | Short-term Investments
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	2	13
Pension Benefits | Level 1 | Other (1)
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	173	114
Pension Benefits | Level 1 | Equity Securities
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	489	436
Pension Benefits | Level 1 | Other invested assets
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	42	41
Pension Benefits | Level 1 | Derivative assets
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	4	10
Pension Benefits | Level 2
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	4,589	5,153
Pension Benefits | Level 2 | Fixed maturity securities AFS
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	4,385	4,924
Pension Benefits | Level 2 | Corporate fixed maturity securities
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	3,025	3,029
Pension Benefits | Level 2 | U.S. government bonds
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	30	38
Pension Benefits | Level 2 | Foreign government
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	729	808
Pension Benefits | Level 2 | Federal agencies
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	83	141
Pension Benefits | Level 2 | Municipals
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	79	147
Pension Benefits | Level 2 | Short-term Investments
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	168	184
Pension Benefits | Level 2 | Other (1)
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	271	577
Pension Benefits | Level 2 | Equity Securities
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	198	162
Pension Benefits | Level 2 | Other invested assets
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	5	0
Pension Benefits | Level 2 | Derivative assets
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	1	67
Pension Benefits | Level 3
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	748	904
Pension Benefits | Level 3 | Fixed maturity securities AFS
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	60	64
Pension Benefits | Level 3 | Corporate fixed maturity securities
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	56	54	55
Pension Benefits | Level 3 | U.S. government bonds
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Pension Benefits | Level 3 | Foreign government
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	2	2	0
Pension Benefits | Level 3 | Federal agencies
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Pension Benefits | Level 3 | Municipals
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Pension Benefits | Level 3 | Short-term Investments
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Pension Benefits | Level 3 | Other (1)
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	2	8	3
Pension Benefits | Level 3 | Equity Securities
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	8	12	3
Pension Benefits | Level 3 | Other invested assets
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	680	828	855
Pension Benefits | Level 3 | Derivative assets
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Other Postretirement Benefits
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	1,329	1,334	$ 1,303
Other Postretirement Benefits | Fixed maturity securities AFS
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	1,270	1,274
Other Postretirement Benefits | Corporate fixed maturity securities
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	175	167
Other Postretirement Benefits | U.S. government bonds
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	109	58
Other Postretirement Benefits | Foreign government
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	38	46
Other Postretirement Benefits | Federal agencies
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	2	1
Other Postretirement Benefits | Municipals
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	5	8
Other Postretirement Benefits | Short-term Investments
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	875	957
Other Postretirement Benefits | Other (1)
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	66	37
Other Postretirement Benefits | Equity Securities
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	58	59
Other Postretirement Benefits | Other invested assets
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	1	1
Other Postretirement Benefits | Derivative assets
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Other Postretirement Benefits | Level 1
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	641	671
Other Postretirement Benefits | Level 1 | Fixed maturity securities AFS
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	582	611
Other Postretirement Benefits | Level 1 | Corporate fixed maturity securities
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Other Postretirement Benefits | Level 1 | U.S. government bonds
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	102	52
Other Postretirement Benefits | Level 1 | Foreign government
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Other Postretirement Benefits | Level 1 | Federal agencies
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	1	1
Other Postretirement Benefits | Level 1 | Municipals
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Other Postretirement Benefits | Level 1 | Short-term Investments
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	469	554
Other Postretirement Benefits | Level 1 | Other (1)
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	10	4
Other Postretirement Benefits | Level 1 | Equity Securities
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	58	59
Other Postretirement Benefits | Level 1 | Other invested assets
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	1	1
Other Postretirement Benefits | Level 1 | Derivative assets
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Other Postretirement Benefits | Level 2
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	688	663
Other Postretirement Benefits | Level 2 | Fixed maturity securities AFS
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	688	663
Other Postretirement Benefits | Level 2 | Corporate fixed maturity securities
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	175	167
Other Postretirement Benefits | Level 2 | U.S. government bonds
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	7	6
Other Postretirement Benefits | Level 2 | Foreign government
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	38	46
Other Postretirement Benefits | Level 2 | Federal agencies
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	1	0
Other Postretirement Benefits | Level 2 | Municipals
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	5	8
Other Postretirement Benefits | Level 2 | Short-term Investments
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	406	403
Other Postretirement Benefits | Level 2 | Other (1)
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	56	33
Other Postretirement Benefits | Level 2 | Equity Securities
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Other Postretirement Benefits | Level 2 | Other invested assets
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Other Postretirement Benefits | Level 2 | Derivative assets
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Other Postretirement Benefits | Level 3
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Other Postretirement Benefits | Level 3 | Fixed maturity securities AFS
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Other Postretirement Benefits | Level 3 | Corporate fixed maturity securities
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Other Postretirement Benefits | Level 3 | U.S. government bonds
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Other Postretirement Benefits | Level 3 | Foreign government
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Other Postretirement Benefits | Level 3 | Federal agencies
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Other Postretirement Benefits | Level 3 | Municipals
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Other Postretirement Benefits | Level 3 | Short-term Investments
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Other Postretirement Benefits | Level 3 | Other (1)
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Other Postretirement Benefits | Level 3 | Equity Securities
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Other Postretirement Benefits | Level 3 | Other invested assets
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Other Postretirement Benefits | Level 3 | Derivative assets
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	$ 0	$ 0