Employee Retirement Benefits (Fair Value Hierarchy Of Assets Measured At Fair Value On A Recurring Basis) (Details) - USD ($) $ in Millions	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Defined Benefit Plan Fair Value Disclosure
Pension plan assets at fair value	$ 397	$ 357	$ 354
Fixed Maturities
Defined Benefit Plan Fair Value Disclosure
Pension plan assets at fair value	49	60
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	18	29
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	7	9
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	7	9
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	11	20
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	11	20
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	332	266
Equity Securities | Level 1
Defined Benefit Plan Fair Value Disclosure
Pension plan assets at fair value	332	266
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	381	326
Fixed Maturities And Equity Securities | Level 1
Defined Benefit Plan Fair Value Disclosure
Pension plan assets at fair value	363	297
Fixed Maturities And Equity Securities | Level 2
Defined Benefit Plan Fair Value Disclosure
Pension plan assets at fair value	18	29
Fixed Maturities And Equity Securities | Level 3
Defined Benefit Plan Fair Value Disclosure
Pension plan assets at fair value	$ 0	$ 0