Municipal Bond Guarantee Reinsurance - Schedule of Municipal Bond Guarantee Insured Obligations (Details) $ in Millions	12 Months Ended
	Dec. 31, 2024 USD ($) contract	Dec. 31, 2023 USD ($) contract
Subsidiary - HG Global | Maximum
Guarantor Obligations [Line Items]
Percentage of par value of policy reinsured	15.00%
HG Global
Guarantor Obligations [Line Items]
Contracts outstanding | contract	15,884	14,485
Remaining weighted average contract period(in years)	11 years 2 months 12 days	11 years 1 month 6 days
Outstanding par value of policies assumed (in millions)	$ 18,503.3	$ 16,575.2
Gross unearned insurance premiums (in millions)	$ 297.3	273.9
HG/BAM
Guarantor Obligations [Line Items]
Outstanding par value of policies assumed (in millions)		109,673.8
Gross unearned insurance premiums (in millions)		325.8
Total debt service outstanding		165,686.0
Interest		$ 56,012.2