Reinsurance and Indemnification - Florida Hurricane Catastrophe Fund (Narrative) (Details) $ in Millions	12 Months Ended
	Dec. 31, 2025 USD ($) contract	Dec. 31, 2024 USD ($)	Dec. 31, 2023 USD ($)
Reinsurance Retention Policy [Line Items]
Property-liability insurance premiums earned	$ 2,681	$ 2,260	$ 2,036
Florida Hurricane Catastrophe Fund
Reinsurance Retention Policy [Line Items]
Property-liability insurance premiums earned	18	23	28
Reinsurance recoverable, qualifying losses (recoveries), amount	$ (28)	(1)	$ (6)
Contracts number | contract	3
Retention level for losses related to hurricanes	$ 173
Percent of losses in excess of retention level to be reimbursed (as a percent)	90.00%
Maximum retention level for losses related to hurricanes	$ 97
Retention level for losses related to other hurricanes	51
Reinsurance and indemnification recoverables, net	$ 29	$ 73
Florida Hurricane Catastrophe Fund | National General Lender Services Standalone Program
Reinsurance Retention Policy [Line Items]
Contracts number | contract	1
Florida Hurricane Catastrophe Fund
Reinsurance Retention Policy [Line Items]
Emergency assessment maximum percentage of premiums first year (as a percent)	6.00%
Emergency assessment maximum percentage of premiums subsequent years (as a percent)	10.00%