Employee Retirement Benefits (Fair Value Hierarchy Of Assets Measured At Fair Value On A Recurring Basis) (Details) - USD ($) $ in Millions	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Defined Benefit Plan Fair Value Disclosure
Pension plan assets at fair value	$ 332	$ 397	$ 357
Fixed Maturities
Defined Benefit Plan Fair Value Disclosure
Pension plan assets at fair value	44	49
Fixed Maturities | Level 1
Defined Benefit Plan Fair Value Disclosure
Pension plan assets at fair value	31	31
Fixed Maturities | Level 2
Defined Benefit Plan Fair Value Disclosure
Pension plan assets at fair value	13	18
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	7
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	7
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	7	11
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	7	11
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	31	31
Fixed Maturities | United States Government | Level 1
Defined Benefit Plan Fair Value Disclosure
Pension plan assets at fair value	31	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	245	332
Equity Securities | Level 1
Defined Benefit Plan Fair Value Disclosure
Pension plan assets at fair value	245	332
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	289	381
Fixed Maturities And Equity Securities | Level 1
Defined Benefit Plan Fair Value Disclosure
Pension plan assets at fair value	276	363
Fixed Maturities And Equity Securities | Level 2
Defined Benefit Plan Fair Value Disclosure
Pension plan assets at fair value	13	18
Fixed Maturities And Equity Securities | Level 3
Defined Benefit Plan Fair Value Disclosure
Pension plan assets at fair value	$ 0	$ 0