v3.26.1
Debt - Additional Information (Details)
3 Months Ended
Jul. 01, 2025
USD ($)
Mar. 31, 2026
USD ($)
extension_option
Dec. 31, 2025
USD ($)
Mar. 31, 2025
USD ($)
Debt Instrument [Line Items]        
Activity-based common stock ownership percentage   0.041    
FHLB stock   $ 33,000,000.0 $ 32,500,000  
Short-term debt, face amount   459,250,000    
FHLB borrowings        
Debt Instrument [Line Items]        
Short-term debt, face amount   70,000,000   $ 0
Estimate of Fair Value Measurement | Asset Pledged as Collateral        
Debt Instrument [Line Items]        
Fair value of pledged assets   $ 1,800,000,000    
Private Placement        
Debt Instrument [Line Items]        
Purchase price of sale of securities $ 500,000,000      
Senior Notes        
Debt Instrument [Line Items]        
Optional redemption, period from issuance date   5 years    
FHLB borrowings        
Debt Instrument [Line Items]        
Maximum borrowing capacity   $ 969,000,000    
Long-term line of credit   $ 482,000,000 $ 437,000,000  
Junior Subordinated Debentures Due 2056        
Debt Instrument [Line Items]        
Interest rate   4.25%    
Senior Notes Due 2055 | Senior Notes        
Debt Instrument [Line Items]        
Interest rate 6.58%      
Facility agreement term 30 years      
Amount of debt $ 500,000,000      
Semi-annual facility fee 1.789%      
Stockholders' equity (excluding AOCI) threshold, triggering exercise of Issuance Right $ 1,850,000,000      
Line of Credit        
Debt Instrument [Line Items]        
Maximum borrowing capacity   $ 1,000,000,000    
Potential maximum borrowing capacity   $ 1,250,000,000    
Number of extension options | extension_option   2    
Extension term   1 year