Income Taxes - Components of Net Deferred Tax Assets (Details) - USD ($) $ in Millions	Dec. 31, 2023	Jan. 01, 2023	Dec. 31, 2022	Dec. 31, 2021
Deferred tax assets:
Unearned premium reserves, net	$ 11		$ 26
Net unrealized investment losses	49		70
Intangible assets	149		0
Value of in-force business	45		0
Rent	15		18
Investments	0		4
Net operating loss	30		37
Depreciation	45		30
Deferred compensation	32		30
Other	6		28
Total deferred tax assets	382		243
Deferred tax liabilities:
Investments	65		0
DAC	12		15
Loss and LAE reserve	13		74
Lease	13		14
Other	29		21
Total deferred tax liabilities	132		124
Less: Valuation allowance	0	$ 2	5	$ 24
Net deferred tax assets (liabilities)	$ 250		$ 114