Income Taxes (Components Of Deferred Tax Assets and Liabilities) (Detail) - USD ($) $ in Millions	Dec. 31, 2023	Dec. 31, 2022
Deferred tax liabilities:
Unearned premium revenue	$ 34	$ 36
Deferred acquisition costs	7	4
Net gains on financial instruments at fair value and foreign exchange	92	121
Net deferred taxes on VIEs	11	27
Total gross deferred tax liabilities	144	188
Deferred tax assets:
Compensation and employee benefits	7	8
Accrued interest	292	259
Loss and loss adjustment expense reserves	62	148
Net operating loss	871	814
Foreign tax credits	56	57
Other-than-temporary impairments and capital loss carryforward	55	16
Net unrealized gains and losses in accumulated other comprehensive income	30	72
Other	16	13
Total gross deferred tax assets	1,389	1,387
Valuation allowance	1,245	1,199
Net deferred tax asset	$ 0	$ 0