v3.26.1
Segment Information - SPPC (Details)
$ in Millions
 3 Months Ended 6 Months Ended
Jun. 30, 2026
USD ($)
Jun. 30, 2025
USD ($)
Jun. 30, 2026
USD ($)
reportableSegment
operatingSegment
Jun. 30, 2025
USD ($)
Dec. 31, 2025
USD ($)
Segment Reporting [Line Items]          
Number of reportable segments | operatingSegment     8    
Revenues $ 6,686 $ 6,394 $ 13,358 $ 12,760  
Cost of sales 1,376 1,434 3,046 2,965  
Interest expense 791 709 1,537 1,395  
Interest and dividend income 67 63 121 125  
Income tax expense (benefit) (333) (357) (763) (756)  
Other segment items (65) (80) (256) (162)  
Net income (loss) attributable to parent 891 702 2,005 1,889  
Capital expenditures 2,531 2,445 4,949 4,573  
Assets 154,029   $ 154,029   $ 148,327
SPPC          
Segment Reporting [Line Items]          
Number of reportable segments | reportableSegment     2    
Revenues 280 258 $ 552 543  
Cost of sales 131 119 262 262  
Operations and maintenance 69 61 140 121  
Depreciation and amortization 48 40 93 80  
Interest expense 36 24 67 48  
Interest and dividend income 3 3 7 6  
Income tax expense (benefit) (3) 3 (2) 6  
Other segment items 34 8 64 17  
Net income (loss) attributable to parent 36 22 63 49  
Capital expenditures 464 341 715 514  
Assets 7,974   7,974   7,045
SPPC | Regulated common assets          
Segment Reporting [Line Items]          
Assets 136   136   19
SPPC | Electric          
Segment Reporting [Line Items]          
Revenues 262 235 497 471  
SPPC | Electric | Operating segments          
Segment Reporting [Line Items]          
Revenues 262 235 497 471  
Cost of sales 127 110 240 225  
Operations and maintenance 63 54 130 107  
Depreciation and amortization 44 35 84 70  
Interest expense 34 22 62 44  
Interest and dividend income 3 3 7 6  
Income tax expense (benefit) (4) 3 (4) 6  
Other segment items 34 8 63 18  
Net income (loss) attributable to parent 35 22 55 43  
Capital expenditures 433 315 668 474  
Assets 7,286   7,286   6,541
SPPC | Natural Gas          
Segment Reporting [Line Items]          
Revenues 18 23 55 72  
SPPC | Natural Gas | Operating segments          
Segment Reporting [Line Items]          
Revenues 18 23 55 72  
Cost of sales 4 9 22 37  
Operations and maintenance 6 7 10 14  
Depreciation and amortization 4 5 9 10  
Interest expense 2 2 5 4  
Interest and dividend income 0 0 0 0  
Income tax expense (benefit) 1 0 2 0  
Other segment items 0 0 1 (1)  
Net income (loss) attributable to parent 1 0 8 6  
Capital expenditures 31 $ 26 47 $ 40  
Assets $ 552   $ 552   $ 485