v3.26.3
Borrowings and Other Financing Instruments, Commercial Paper (Details) - USD ($)
$ in Millions
 3 Months Ended
Sep. 30, 2026
Dec. 31, 2025
Revolving Credit Facility [Member]    
Short-term Debt [Line Items]    
Line of Credit Facility, Maximum Borrowing Capacity [1] $ 150  
Commercial Paper    
Short-term Debt [Line Items]    
Line of Credit Facility, Maximum Borrowing Capacity 150 $ 150
Amount outstanding at period end 0 0
Average amount outstanding 0 3
Maximum amount outstanding 0 $ 50
Weighted average interest rate, computed on a daily basis   4.57%
Money Pool    
Short-term Debt [Line Items]    
Line of Credit Facility, Maximum Borrowing Capacity 150 $ 150
Amount outstanding at period end 0 8
Average amount outstanding 0 2
Maximum amount outstanding $ 0 $ 42
Weighted average interest rate, computed on a daily basis   4.25%
Weighted average interest rate at period end   3.88%
[1] Expires in December 2029.