Fair Value Measurements (Fair Value Of Deferred Annuities, Structured Settlements And Other Items) (Details) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis
Fair value of deferred annuities and structured settlements	$ 1,063	$ 982
Deferred Annuities
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis
Fair value of deferred annuities and structured settlements	836	770
Structured Settlements
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis
Fair value of deferred annuities and structured settlements	227	212
Level 1
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis
Fair value of deferred annuities and structured settlements	0	0
Level 1 | Deferred Annuities
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis
Fair value of deferred annuities and structured settlements	0	0
Level 1 | Structured Settlements
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis
Fair value of deferred annuities and structured settlements	0	0
Level 2
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis
Fair value of deferred annuities and structured settlements	227	212
Level 2 | Deferred Annuities
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis
Fair value of deferred annuities and structured settlements	0	0
Level 2 | Structured Settlements
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis
Fair value of deferred annuities and structured settlements	227	212
Level 3
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis
Fair value of deferred annuities and structured settlements	836	770
Level 3 | Deferred Annuities
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis
Fair value of deferred annuities and structured settlements	836	770
Level 3 | Structured Settlements
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis
Fair value of deferred annuities and structured settlements	$ 0	$ 0