Employee Retirement Benefits (Fair Value Hierarchy Of Assets Measured At Fair Value On A Recurring Basis) (Details) - USD ($) $ in Millions	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Defined Benefit Plan Fair Value Disclosure
Pension plan assets at fair value	$ 317	$ 332	$ 397
Fixed Maturities
Defined Benefit Plan Fair Value Disclosure
Pension plan assets at fair value	32	44
Fixed Maturities | Level 1
Defined Benefit Plan Fair Value Disclosure
Pension plan assets at fair value	22	31
Fixed Maturities | Level 2
Defined Benefit Plan Fair Value Disclosure
Pension plan assets at fair value	10	13
Fixed Maturities | Level 3
Defined Benefit Plan Fair Value Disclosure
Pension plan assets at fair value	0	0
Fixed Maturities | States, Municipalities and Political Subdivisions
Defined Benefit Plan Fair Value Disclosure
Pension plan assets at fair value	6	6
Fixed Maturities | States, Municipalities and Political Subdivisions | Level 1
Defined Benefit Plan Fair Value Disclosure
Pension plan assets at fair value	0	0
Fixed Maturities | States, Municipalities and Political Subdivisions | Level 2
Defined Benefit Plan Fair Value Disclosure
Pension plan assets at fair value	6	6
Fixed Maturities | States, Municipalities and Political Subdivisions | Level 3
Defined Benefit Plan Fair Value Disclosure
Pension plan assets at fair value	0	0
Fixed Maturities | Domestic Corporate Debt Securities
Defined Benefit Plan Fair Value Disclosure
Pension plan assets at fair value	4	7
Fixed Maturities | Domestic Corporate Debt Securities | Level 1
Defined Benefit Plan Fair Value Disclosure
Pension plan assets at fair value	0	0
Fixed Maturities | Domestic Corporate Debt Securities | Level 2
Defined Benefit Plan Fair Value Disclosure
Pension plan assets at fair value	4	7
Fixed Maturities | Domestic Corporate Debt Securities | Level 3
Defined Benefit Plan Fair Value Disclosure
Pension plan assets at fair value	0	0
Fixed Maturities | United States Government
Defined Benefit Plan Fair Value Disclosure
Pension plan assets at fair value	22	31
Fixed Maturities | United States Government | Level 1
Defined Benefit Plan Fair Value Disclosure
Pension plan assets at fair value	22	31
Fixed Maturities | United States Government | Level 2
Defined Benefit Plan Fair Value Disclosure
Pension plan assets at fair value	0	0
Fixed Maturities | United States Government | Level 3
Defined Benefit Plan Fair Value Disclosure
Pension plan assets at fair value	0	0
Equity Securities
Defined Benefit Plan Fair Value Disclosure
Pension plan assets at fair value	269	245
Equity Securities | Level 1
Defined Benefit Plan Fair Value Disclosure
Pension plan assets at fair value	269	245
Equity Securities | Level 2
Defined Benefit Plan Fair Value Disclosure
Pension plan assets at fair value	0	0
Equity Securities | Level 3
Defined Benefit Plan Fair Value Disclosure
Pension plan assets at fair value	0	0
Fixed Maturities And Equity Securities
Defined Benefit Plan Fair Value Disclosure
Pension plan assets at fair value	301	289
Fixed Maturities And Equity Securities | Level 1
Defined Benefit Plan Fair Value Disclosure
Pension plan assets at fair value	291	276
Fixed Maturities And Equity Securities | Level 2
Defined Benefit Plan Fair Value Disclosure
Pension plan assets at fair value	10	13
Fixed Maturities And Equity Securities | Level 3
Defined Benefit Plan Fair Value Disclosure
Pension plan assets at fair value	$ 0	$ 0