v3.26.1
Recent Financing Transactions - NPC (Details) - NPC - USD ($)
$ in Millions
1 Months Ended 3 Months Ended
Mar. 31, 2026
Mar. 31, 2026
Mar. 31, 2025
Debt Instrument [Line Items]      
Repayments of debt   $ 93 $ 0
NPC Pollution Control Refunding Revenue Bonds, 3.750%, Series 2017, Due 2036 | Subsidiary debt      
Debt Instrument [Line Items]      
Repayments of debt $ 40    
NPC Pollution Control Refunding Revenue Bonds, 4.125%, Series 2017A, Due 2032 | Subsidiary debt      
Debt Instrument [Line Items]      
Repayments of debt 40    
NPC Pollution Control Refunding Revenue Bonds, 3.750%, Series 2017B, due 2039 | Subsidiary debt      
Debt Instrument [Line Items]      
Repayments of debt $ 13