Insurance Company Subsidiary Operations - Additional Information (Details) $ in Millions			1 Months Ended	3 Months Ended	6 Months Ended	12 Months Ended	31 Months Ended
	Jun. 10, 2024 USD ($)	Apr. 28, 2023 USD ($)	Dec. 31, 2021 USD ($)	Jun. 30, 2024 USD ($)	Jun. 30, 2024 USD ($) Reinsurer	Dec. 31, 2023 USD ($)	Jun. 30, 2024 USD ($)	Jun. 30, 2023 USD ($)
SEC Schedule, 12-17, Insurance Companies, Reinsurance [Line Items]
Ceded rate of premiums under insurance program				100.00%	100.00%		100.00%
Ceded unpaid loss				$ 98	$ 98		$ 98
Prepaid reinsurance premiums				483	483	$ 462	483
Increase (decrease) in loss and loss adjustment expense reserve					0
Reinsurance recoverable				100	100	125	100
Reserve for losses and loss adjustment expense				98	$ 98		98
Number of reinsurers | Reinsurer					2
Premium net written					$ 106
Net earned premiums					28
Ultimate loss reserve expense inclusive of IBNR claims				108	108	131	108
Hurricane Ian
SEC Schedule, 12-17, Insurance Companies, Reinsurance [Line Items]
Loss reserve inclusive of IBNR claims				3	3		3	$ 3
Reported insured losses				$ 2	$ 2		$ 2
Wright National Flood Insurance Company
SEC Schedule, 12-17, Insurance Companies, Reinsurance [Line Items]
Ceded rate of premiums under insurance program				100.00%	100.00%		100.00%
Prepaid reinsurance premiums				$ 483	$ 483		$ 483
Expenses and allowance rate received in premiums				29.50%	29.50%		29.50%
Premiums written net					$ 475
Ceded to highly rated carriers for excess flood policies					2
Statutory capital and surplus required				$ 8	8		$ 8
Statutory capital and surplus				$ 42	42	39	$ 42
Statutory net Income					$ 9	$ 7
Percentage of adjusted net income				100.00%	100.00%		100.00%
Maximum dividend payout that may be made without prior approval				$ 7	$ 7		$ 7
Dividend paid	$ 7	$ 3
Wright National Flood Insurance Company | Maximum
SEC Schedule, 12-17, Insurance Companies, Reinsurance [Line Items]
Preferred stock, dividend rate, percentage					10.00%
Wright National Flood Insurance Company | FEMA
SEC Schedule, 12-17, Insurance Companies, Reinsurance [Line Items]
Premiums written net					$ 473
Quota Share Captive
SEC Schedule, 12-17, Insurance Companies, Reinsurance [Line Items]
Deferred acquisitions costs				63	63		63
Reinsurance payable				6	6		6
Reserve for losses and loss adjustment expense				7	7		7
Premiums written net					22
Premium net written				106
Net earned premiums				27
Initial funding			$ 6
Addition to earnings							4
Ultimate loss reserve expense inclusive of IBNR claims				$ 11	11		$ 11	$ 11
Captive Insurance Facility
SEC Schedule, 12-17, Insurance Companies, Reinsurance [Line Items]
Maximum aggregate annual underwriting exposure					$ 2