Related-Party Transactions (Premiums And Losses Ceded By The Company To Affiliate) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021
Mt Logan Re [Member]
Effects of Reinsurance [Line Items]
Ceded written premiums	$ 60	$ 98	$ 122	$ 226
Ceded earned premiums	51	86	122	212
Ceded losses and LAE	82	97	142	192
Bermuda Re [Member]
Effects of Reinsurance [Line Items]
Ceded written premiums	95	78	279	224
Ceded earned premiums	95	77	279	222
Ceded losses and LAE	(2)	12	(1)	3
Assumed written premiums		5	3	5
Assumed earned premiums		4	5	4
Assumed losses and LAE
Ireland Re [Member]
Effects of Reinsurance [Line Items]
Assumed written premiums	2	7	6	13
Assumed earned premiums	2	7	6	12
Assumed losses and LAE	(4)	62	(2)	62
Ireland Insurance [Member]
Effects of Reinsurance [Line Items]
Assumed written premiums	3	4	7	6
Assumed earned premiums	2	2	6	4
Assumed losses and LAE	$ 1	$ 1	$ 3	$ 2