v3.26.1
Debt and Credit Agreements - Issuances and Redemptions (Details) - USD ($)
$ in Millions
3 Months Ended
Mar. 31, 2026
Mar. 31, 2025
Debt Instrument [Line Items]    
Retirement of long-term debt $ (5,254) $ (57)
Total long-term debt issued (redeemed) (2,484)  
2028 Senior Notes    
Debt Instrument [Line Items]    
Issuance $ 900  
Interest Rate 390.00%  
2066 Senior Notes    
Debt Instrument [Line Items]    
Issuance $ 800  
Interest Rate 587.50%  
2031 Senior Unsecured Notes    
Debt Instrument [Line Items]    
Issuance $ 750  
Interest Rate 440.00%  
2028 Floating Rate Senior Notes    
Debt Instrument [Line Items]    
Issuance $ 300  
Basis spread 0.60%  
Pin Oak Creek Energy Center    
Debt Instrument [Line Items]    
Issuance $ 16  
Interest Rate 300.00%  
Energy Efficiency Project Financing    
Debt Instrument [Line Items]    
Issuance $ 4  
Interest Rate 551.00%  
RPG Nonrecourse Debt    
Debt Instrument [Line Items]    
Retirement of long-term debt $ (2)  
Interest Rate 411.00%  
2031 Unsecured Notes    
Debt Instrument [Line Items]    
Retirement of long-term debt $ (2)  
Interest Rate 500.00%  
2029 Unsecured Notes    
Debt Instrument [Line Items]    
Retirement of long-term debt $ (3)  
Interest Rate 462.50%  
Antelope Valley DOE Nonrecourse Debt    
Debt Instrument [Line Items]    
Retirement of long-term debt $ (6)  
Antelope Valley DOE Nonrecourse Debt | Maximum    
Debt Instrument [Line Items]    
Interest Rate 3.56%  
Antelope Valley DOE Nonrecourse Debt | Minimum    
Debt Instrument [Line Items]    
Interest Rate 2.29%  
Greenfield    
Debt Instrument [Line Items]    
Retirement of long-term debt $ (7)  
Basis spread 1.875%  
Nova Power    
Debt Instrument [Line Items]    
Retirement of long-term debt $ (10)  
Basis spread 1.75%  
Calpine Development Holdings    
Debt Instrument [Line Items]    
Retirement of long-term debt $ (11)  
Basis spread 2.25%  
Continental Wind Nonrecourse Debt    
Debt Instrument [Line Items]    
Retirement of long-term debt $ (18)  
Interest Rate 600.00%  
Geysers Power Company    
Debt Instrument [Line Items]    
Retirement of long-term debt $ (35)  
Basis spread 1.625%  
Calpine Term Loan B-5    
Debt Instrument [Line Items]    
Retirement of long-term debt $ (860)  
Basis spread 1.75%  
Calpine Senior Secured Notes    
Debt Instrument [Line Items]    
Retirement of long-term debt $ (1,250)  
Interest Rate 450.00%  
Calpine Senior Unsecured Notes    
Debt Instrument [Line Items]    
Retirement of long-term debt $ (1,400)  
Interest Rate 512.50%  
Calpine Term Loan B-10    
Debt Instrument [Line Items]    
Retirement of long-term debt $ (1,650)  
Basis spread 1.75%