v3.26.1
Related Party Transactions - Narrative (Details)
$ in Millions
 12 Months Ended
Dec. 31, 2025
USD ($)
Dec. 31, 2024
USD ($)
Dec. 31, 2023
USD ($)
Dec. 31, 2022
USD ($)
Related Party Transaction [Line Items]        
Plus component of annual investment management fee 0.25      
Annual fee cap 0.15      
Privately-held Investments [1] $ 121.8 $ 286.8    
Other Investments [2] 279.6 267.2    
Net Investment Income 326.3 [3] 318.0 $ 275.7  
Accrued expenses and other payables [4] 317.1 237.2    
Gain (loss) on investments 61.4 52.6 75.9  
Net premiums earned [5] 2,831.9 2,889.7 2,614.5  
Losses and loss adjustment expenses [5] 1,546.7 1,717.8 1,553.0  
Premiums Receivable, Net [6] 1,700.8 1,617.0    
Liability for Claims and Claims Adjustment Expense 8,725.0 [6] 8,122.6 [6] 7,810.6 $ 7,710.9
Unearned Premiums [6] 2,725.8 2,645.8    
Asset Management Arrangement        
Related Party Transaction [Line Items]        
Net Investment Income 6.4 9.2 9.4  
Accrued expenses and other payables 2.0 4.0    
Apollo real estate fund        
Related Party Transaction [Line Items]        
Gain (loss) on investments 2.1 0.4 (0.4)  
Apollo real estate fund | Fair Value, Recurring [Member]        
Related Party Transaction [Line Items]        
Other Investments 81.4      
Beneficial owner        
Related Party Transaction [Line Items]        
Accounts Payable, Current 0.0 1.2    
Funds managed by Apollo | Fair Value, Recurring [Member]        
Related Party Transaction [Line Items]        
Other Investments 81.4 78.6    
Apollo Notes, SPV        
Related Party Transaction [Line Items]        
Privately-held investment, losses incurred (3.4) (5.5) 5.5  
Apollo Notes, SPV | Fair Value, Recurring [Member]        
Related Party Transaction [Line Items]        
Privately-held Investments 0.0 66.6    
CLOs        
Related Party Transaction [Line Items]        
Net Investment Income 8.3 11.3 17.4  
CLOs | Fair Value, Recurring [Member]        
Related Party Transaction [Line Items]        
Debt Securities, Trading 88.8 88.9    
Middle Market Term Loans managed by a subsidiary of Apollo        
Related Party Transaction [Line Items]        
Net Investment Income (1.9) 0.5 $ 5.8  
Middle Market Term Loans managed by a subsidiary of Apollo | Fair Value, Recurring [Member]        
Related Party Transaction [Line Items]        
Debt Securities, Trading 4.8 $ 7.0    
Apollo and Subsidiaries        
Related Party Transaction [Line Items]        
Net premiums earned 5.9      
Losses and loss adjustment expenses 3.7      
Premiums Receivable, Net 1.6      
Liability for Claims and Claims Adjustment Expense 3.7      
Unearned Premiums $ 1.2      
Maximum        
Related Party Transaction [Line Items]        
Percentage of consolidated group's net income due to Apollo Management 1.00%      
Dollar amount option to percentage fee $ 5.0      
[1] Privately-held investments, trading at fair value include related party investments totaling $4.8 million (2024 — $73.6 million).
[2] Other investments includes related party investments of $81.4 million (2024 — $78.6 million).
[3] Net investment income includes related party net investment income of $13.6 million (2024 — $15.2 million, 2023 — $19.6 million) and related party investment management fees of $6.4 million (2024 — $9.2 million, 2023 — $9.4 million).
[4] Includes amounts due to related parties of $2.0 million for investment management fees (2024 — $4.0 million), and $Nil for management consulting fees (2024 — $1.3 million).
[5] Net earned premiums and losses and loss adjustment expenses include related party balances of $5.9 million and $3.7 million, respectively, for the twelve months ended December 31, 2025. Refer to Note 20, “Related Party Transactions” for further details.
[6] Included within underwriting premiums receivables, reserve for losses and loss adjustment expenses and unearned premiums are related party balances of $1.6 million, $3.7 million and $1.2 million, respectively. Refer to Note 20, “Related Party Transactions” for further details.