v3.26.1
Revenue from Contracts with Customers - SPPC (Details) - USD ($)
$ in Millions
3 Months Ended 6 Months Ended
Jun. 30, 2026
Jun. 30, 2025
Jun. 30, 2026
Jun. 30, 2025
Disaggregation of Revenue [Line Items]        
Operating revenue $ 6,686 $ 6,394 $ 13,358 $ 12,760
Regulated | Regulated retail electric        
Disaggregation of Revenue [Line Items]        
Total Customer Revenue 3,278 3,146 6,246 5,970
Regulated | Regulated retail gas        
Disaggregation of Revenue [Line Items]        
Total Customer Revenue 119 127 488 485
SPPC        
Disaggregation of Revenue [Line Items]        
Other revenue 1 1 1 1
Operating revenue 280 258 552 543
SPPC | Electric        
Disaggregation of Revenue [Line Items]        
Other revenue 1 1 1 1
Operating revenue 262 235 497 471
SPPC | Natural Gas        
Disaggregation of Revenue [Line Items]        
Other revenue 0 0 0 0
Operating revenue 18 23 55 72
SPPC | Regulated        
Disaggregation of Revenue [Line Items]        
Total Customer Revenue 279 257 551 542
SPPC | Regulated | Wholesale, transmission and other        
Disaggregation of Revenue [Line Items]        
Total Customer Revenue 10 13 32 31
SPPC | Regulated | Electric        
Disaggregation of Revenue [Line Items]        
Total Customer Revenue 261 234 496 470
SPPC | Regulated | Electric | Wholesale, transmission and other        
Disaggregation of Revenue [Line Items]        
Total Customer Revenue 13 13 32 31
SPPC | Regulated | Natural Gas        
Disaggregation of Revenue [Line Items]        
Total Customer Revenue 18 23 55 72
SPPC | Regulated | Natural Gas | Wholesale, transmission and other        
Disaggregation of Revenue [Line Items]        
Total Customer Revenue (3) 0 0 0
SPPC | Regulated | Total retail        
Disaggregation of Revenue [Line Items]        
Total Customer Revenue 269 244 519 511
SPPC | Regulated | Total retail | Electric | Regulated retail electric        
Disaggregation of Revenue [Line Items]        
Total Customer Revenue 248 221 464 439
SPPC | Regulated | Total retail | Natural Gas | Regulated retail gas        
Disaggregation of Revenue [Line Items]        
Total Customer Revenue 21 23 55 72
SPPC | Regulated | Customer Revenue        
Disaggregation of Revenue [Line Items]        
Total Customer Revenue 267 242 515 507
SPPC | Regulated | Customer Revenue | Residential        
Disaggregation of Revenue [Line Items]        
Total Customer Revenue 102 95 214 220
SPPC | Regulated | Customer Revenue | Commercial        
Disaggregation of Revenue [Line Items]        
Total Customer Revenue 91 88 172 174
SPPC | Regulated | Customer Revenue | Industrial        
Disaggregation of Revenue [Line Items]        
Total Customer Revenue 72 58 126 110
SPPC | Regulated | Customer Revenue | Other retail        
Disaggregation of Revenue [Line Items]        
Total Customer Revenue 2 1 3 3
SPPC | Regulated | Customer Revenue | Electric | Regulated retail electric        
Disaggregation of Revenue [Line Items]        
Total Customer Revenue 246 219 460 435
SPPC | Regulated | Customer Revenue | Electric | Regulated retail electric | Residential        
Disaggregation of Revenue [Line Items]        
Total Customer Revenue 88 80 177 173
SPPC | Regulated | Customer Revenue | Electric | Regulated retail electric | Commercial        
Disaggregation of Revenue [Line Items]        
Total Customer Revenue 87 83 159 156
SPPC | Regulated | Customer Revenue | Electric | Regulated retail electric | Industrial        
Disaggregation of Revenue [Line Items]        
Total Customer Revenue 70 56 122 104
SPPC | Regulated | Customer Revenue | Electric | Regulated retail electric | Other retail        
Disaggregation of Revenue [Line Items]        
Total Customer Revenue 1 0 2 2
SPPC | Regulated | Customer Revenue | Natural Gas | Regulated retail gas        
Disaggregation of Revenue [Line Items]        
Total Customer Revenue 21 23 55 72
SPPC | Regulated | Customer Revenue | Natural Gas | Regulated retail gas | Residential        
Disaggregation of Revenue [Line Items]        
Total Customer Revenue 14 15 37 47
SPPC | Regulated | Customer Revenue | Natural Gas | Regulated retail gas | Commercial        
Disaggregation of Revenue [Line Items]        
Total Customer Revenue 4 5 13 18
SPPC | Regulated | Customer Revenue | Natural Gas | Regulated retail gas | Industrial        
Disaggregation of Revenue [Line Items]        
Total Customer Revenue 2 2 4 6
SPPC | Regulated | Customer Revenue | Natural Gas | Regulated retail gas | Other retail        
Disaggregation of Revenue [Line Items]        
Total Customer Revenue 1 1 1 1
SPPC | Regulated | Distribution only service        
Disaggregation of Revenue [Line Items]        
Total Customer Revenue 2 2 4 4
SPPC | Regulated | Distribution only service | Electric | Regulated retail electric        
Disaggregation of Revenue [Line Items]        
Total Customer Revenue 2 2 4 4
SPPC | Regulated | Distribution only service | Natural Gas | Regulated retail gas        
Disaggregation of Revenue [Line Items]        
Total Customer Revenue $ 0 $ 0 $ 0 $ 0