Reserve For Losses, LAE And Future Policy Benefit Reserve (Summary Of Incurred Losses With Respect To A&E Reserve On Both Gross And Net Of Reinsurance Basis) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Reserve For Losses, LAE And Future Policy Benefit Reserve [Abstract]
Gross basis: Beginning of period reserves	$ 175	$ 219	$ 258
Gross basis: Incurred losses	144	11	2
Gross basis: Paid losses	(42)	(55)	(40)
Gross basis: End of period reserves	278	175	219
Net basis: Beginning of period reserves	156	198	229
Net basis: Incurred losses	138		(1)
Net basis: Paid losses	(37)	(42)	(30)
Net basis: End of period reserves	$ 257	$ 156	$ 198