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	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance	$ 610	$ 481	$ 581	$ 449
Total gains (losses) recognized in net income	1	(7)	(7)	(3)
Total gains (losses) recognized in accumulated other comprehensive loss	(8)		(2)	(2)
Purchases	9	212	23	260
Sales	(20)	(202)	(30)	(191)
Settlements	(4)	(5)	(6)	(39)
Transfers into Level III	6	14	6	14
Transfers out of Level III	(50)	(26)	(21)	(21)
Ending balance	544	467	544	467
Change in unrealized gains (losses) included in net income related to assets still held	1	(3)	(6)	1
Corporate Securities [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance	142	341	137	336
Total gains (losses) recognized in net income	(2)	(5)	(3)	(4)
Total gains (losses) recognized in accumulated other comprehensive loss	1		2	(2)
Purchases	2	11	4	35
Sales	(10)	(188)	(10)	(175)
Settlements	(4)	(5)	(6)	(39)
Transfers into Level III	0	14	0	14
Transfers out of Level III	(26)	(13)	(21)	(10)
Ending balance	103	155	103	155
Change in unrealized gains (losses) included in net income related to assets still held	0	0	0	0
Residential Mortgage-Backed Securities [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance	0	4	0	5
Total gains (losses) recognized in net income	0	0	0	0
Total gains (losses) recognized in accumulated other comprehensive loss	0		0	0
Purchases	0	0	0	0
Sales	0	0	0	0
Settlements	0	0	0	0
Transfers into Level III	0	0	0	0
Transfers out of Level III	0	(4)	0	(5)
Ending balance	0	0	0	0
Change in unrealized gains (losses) included in net income related to assets still held	0	0	0	0
Other Asset-backed Securities [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance	390	37	356	19
Total gains (losses) recognized in net income	1	0	1	0
Total gains (losses) recognized in accumulated other comprehensive loss	(9)		(4)	0
Purchases	7	190	18	205
Sales	(5)	0	(11)	0
Settlements	0	0	0	0
Transfers into Level III	6	0	6	0
Transfers out of Level III	(24)	(9)	0	(6)
Ending balance	366	218	366	218
Change in unrealized gains (losses) included in net income related to assets still held	0	0	0	0
Equity Securities [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance	78	99	88	89
Total gains (losses) recognized in net income	2	(2)	(5)	1
Total gains (losses) recognized in accumulated other comprehensive loss	0		0	0
Purchases	0	11	1	20
Sales	(5)	(14)	(9)	(16)
Settlements	0	0	0	0
Transfers into Level III	0	0	0	0
Transfers out of Level III	0	0	0	0
Ending balance	75	94	75	94
Change in unrealized gains (losses) included in net income related to assets still held	$ 1	$ (3)	$ (6)	$ 1