Income Taxes - Significant components of deferred tax assets and liabilities (Details) - USD ($) $ in Millions	Dec. 31, 2023	Dec. 31, 2022
Deferred tax assets:
Federal net operating loss carryforwards	$ 2	$ 2
Foreign underwriting losses	10	10
Insurance claims and reserves	269	255
Employee benefits	111	108
Other, net	25	24
Total deferred tax assets before valuation allowance	417	399
Valuation allowance against deferred tax assets	(14)	(16)
Total deferred tax assets	403	383
Deferred tax liabilities:
Investment securities	(177)	(52)
Deferred policy acquisition costs	(70)	(66)
Insurance claims and reserves transition liability	(8)	(12)
Real estate, property and equipment	(12)	(23)
Total deferred tax liabilities	(267)	(153)
Net deferred tax asset	$ 136	$ 230