Income Taxes (Components Of Deferred Tax Assets And Liabilities) (Details) - USD ($) $ in Millions	Dec. 31, 2023	Dec. 31, 2022
Deferred tax assets:
Unearned premiums	$ 165	$ 148
Loss and loss expense reserves	120	106
Net operating loss on international earnings	26	28
Deferred international earnings	0	16
Other	70	55
Deferred tax assets before valuation allowance	381	353
Valuation allowance for international operations	0	31
Deferred tax assets net of valuation allowance	381	322
Deferred tax liabilities:
Investment gains and other, net	1,290	992
Deferred acquisition costs	184	171
Life policy reserves	104	121
Deferred international earnings	21	0
Investments	35	31
Other	71	61
Total gross deferred tax liabilities	1,705	1,376
Net deferred income tax liability	$ 1,324	$ 1,054