Fair Value (Reconciliation Of The Beginning And Ending Balances Of Assets Measured At Fair Value On A Recurring Basis Using Level III Inputs) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance	$ 449	$ 392	$ 397
Gains (losses) recognized in net income	$ (1)	$ 19	$ (22)
Fair Value, Asset, Recurring Basis, Unobservable Input Reconciliation, Gain (Loss), Statement of Income or Comprehensive Income [Extensible Enumeration]	Net Income	Net Income	Net Income
Gains (losses) recognized in accumulated other comprehensive loss/income	$ (17)	$ 3	$ (5)
Purchases	443	216	101
Sales	(242)	(22)	(41)
Settlements	(41)	(157)	(46)
Transfers into Level III	9	3	10
Transfers out of Level III	(19)	(5)	(2)
Ending balance	581	449	392
Change in unrealized losses included in net income related to assets still held	0	18	(19)
Corporate Securities [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance	336	325	303
Gains (losses) recognized in net income	0	2	(3)
Gains (losses) recognized in accumulated other comprehensive loss/income	(1)	3	(5)
Purchases	56	179	85
Sales	(210)	(18)	(19)
Settlements	(41)	(157)	(44)
Transfers into Level III	9	3	10
Transfers out of Level III	(12)	(1)	(2)
Ending balance	137	336	325
Change in unrealized losses included in net income related to assets still held	0	0	0
Residential Mortgage-Backed Securities [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance	5	2	2
Gains (losses) recognized in net income	0	0	0
Gains (losses) recognized in accumulated other comprehensive loss/income	0	0	0
Purchases	0	4	0
Sales	0	0	0
Settlements	0	0	0
Transfers into Level III	0	0	0
Transfers out of Level III	(5)	(1)	0
Ending balance	0	5	2
Change in unrealized losses included in net income related to assets still held	0	0	0
Other Asset-Backed Securities [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance	19	5	7
Gains (losses) recognized in net income	(1)	0	0
Gains (losses) recognized in accumulated other comprehensive loss/income	(16)	0	0
Purchases	370	17	0
Sales	(14)	0	0
Settlements	0	0	(2)
Transfers into Level III	0	0	0
Transfers out of Level III	(2)	(3)	0
Ending balance	356	19	5
Change in unrealized losses included in net income related to assets still held	0	0	0
Equity Securities [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance	89	60	85
Gains (losses) recognized in net income	0	17	(19)
Gains (losses) recognized in accumulated other comprehensive loss/income	0	0	0
Purchases	17	16	16
Sales	(18)	(4)	(22)
Settlements	0	0	0
Transfers into Level III	0	0	0
Transfers out of Level III	0	0	0
Ending balance	88	89	60
Change in unrealized losses included in net income related to assets still held	$ 0	$ 18	$ (19)