Income Taxes - Significant components of deferred tax assets and liabilities (Details) - USD ($) $ in Millions	Dec. 31, 2024	Dec. 31, 2023
Deferred tax assets:
Federal net operating loss carryforwards	$ 2	$ 2
Foreign underwriting losses	10	10
Insurance claims and reserves	283	269
Employee benefits	114	111
Deferred Tax Assets, Lease Liabilities	45	38
Other, net	20	23
Total deferred tax assets before valuation allowance	474	453
Valuation allowance against deferred tax assets	(11)	(14)
Total deferred tax assets	463	439
Deferred tax liabilities:
Investment securities	(233)	(177)
Deferred policy acquisition costs	(73)	(70)
Insurance claims and reserves transition liability	(4)	(8)
Deferred Tax Liabilities, Leasing Arrangements	42	36
Real estate, property and equipment	(7)	(12)
Total deferred tax liabilities	(359)	(303)
Net deferred tax asset	$ 104	$ 136