v3.26.1
Borrowings and Other Financing Instruments - Borrowings and Other Financing Instruments, Long-Term Borrowings and Other Financing Instruments (Details) - Bonds [Member]
$ in Millions
Jun. 30, 2026
USD ($)
Series Due March 13, 2029  
Debt Instrument [Line Items]  
Debt Instrument, Face Amount $ 700
Debt Instrument, Interest Rate, Stated Percentage 4.15%
Series Due June 15, 2036  
Debt Instrument [Line Items]  
Debt Instrument, Face Amount $ 600
Debt Instrument, Interest Rate, Stated Percentage 5.05%