v3.25.2
Borrowings and Other Financing Instruments Commercial Paper (Details) - USD ($)
$ in Millions
3 Months Ended 12 Months Ended
Jun. 30, 2025
Dec. 31, 2024
Short-term Debt [Line Items]    
Amount outstanding at period end $ 0 $ 195
Commercial Paper    
Short-term Debt [Line Items]    
Borrowing limit 800 700
Amount outstanding at period end 0 195
Average amount outstanding 14 54
Maximum amount outstanding $ 85 $ 400
Weighted average interest rate, computed on a daily basis 4.66% 5.39%
Weighted average interest rate at period end   4.63%