Reinsurance and Indemnification - Michigan Catastrophic Claims Association (Details) - USD ($)	6 Months Ended	12 Months Ended	24 Months Ended
	Jun. 30, 2021	Dec. 31, 2021	Jun. 30, 2023	Jun. 30, 2021	Nov. 03, 2021	Dec. 31, 2020
Reinsurance Retention Policy [Line Items]
Assets		$ 99,440,000,000				$ 125,987,000,000
Retained income		53,294,000,000				52,767,000,000
Michigan Catastrophic Claim Association
Reinsurance Retention Policy [Line Items]
Reinsurance and indemnification recoverables, net		6,700,000,000				$ 5,650,000,000
Program funding, per vehicle annual assessment		$ 86
Reinsurance increase, percentage		6.00%
Retention level per claim				$ 580,000
Term of catastrophe reinsurance agreement contract				2 years
Assets	$ 27,260,000,000			$ 27,260,000,000
Retained income	5,040,000,000.00			$ 5,040,000,000.00
Retained earnings accumulated deficit decrease	$ 31,280,000,000
Program surplus, per vehicle refund					$ 400
Program surplus, per historical vehicle refund					$ 80
Subsequent Event | Michigan Catastrophic Claim Association
Reinsurance Retention Policy [Line Items]
Retention level per claim			$ 600,000
Term of catastrophe reinsurance agreement contract			2 years