Other Comprehensive Income (Loss) (Reclassification From Accumulated Other Comprehensive Income) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Income tax expense (benefit)	$ 9	$ (167)	$ (71)
NET INCOME (LOSS)	597	1,379	$ 514
URA(D) On Securities [Member] | Reclassification From Accumulated Other Comprehensive Income [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Other net realized capital gains (losses)	107	5
Income tax expense (benefit)	(18)	(2)
NET INCOME (LOSS)	89	4
Benefit Plan Net Gain (Loss) [Member] | Reclassification From Accumulated Other Comprehensive Income [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Other underwriting expenses	3	8
Income tax expense (benefit)	(1)	(2)
NET INCOME (LOSS)	$ 2	$ 6