v3.26.1
BORROWINGS AND BORROWING CAPACITY - Narrative (Details) - USD ($)
Dec. 13, 2024
Mar. 31, 2026
Dec. 31, 2025
Debt Instrument [Line Items]      
Letters of credit, outstanding amount   $ 1,230,000,000 $ 2,170,000,000
Revolving Credit Agreement | Loan Agreement | Line of Credit      
Debt Instrument [Line Items]      
Maximum borrowing capacity $ 75,000,000.0    
Letters of credit, outstanding amount   0  
Interest payment period (in months) 24 months    
Debt service ratio 1.25    
Texas ratio (as a percent) 0.200    
Leverage ratio (as a percent) 0.080    
Federal Home Loan Bank of Dallas      
Debt Instrument [Line Items]      
Maximum borrowing capacity   3,170,000,000  
Remaining borrowing capacity   1,810,000,000  
Federal Home Loan Bank of Dallas | Federal Home Loan Bank Advances | Weighted Average      
Debt Instrument [Line Items]      
Federal Home Loan Bank, advances, interest rate (as a percent) 2.75%    
Federal Home Loan Bank of Dallas | Federal Home Loan Bank Letters Of Credit      
Debt Instrument [Line Items]      
Outstanding amount   1,230,000,000  
Federal Home Loan Bank of Dallas | Federal Home Loan Bank Advances      
Debt Instrument [Line Items]      
Short-term debt   $ 135,000,000.0  
Weighted average interest rate (as a percent)   3.77%