v3.26.1
Revenue Recognition - Disaggregated Revenues (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]        
Revenues from Contracts with Customers $ 1,350 $ 1,272 $ 2,553 $ 2,406
Other revenues not from contracts with customers 5 4 9 12
Operating revenues 1,355 1,276 2,562 2,418
Other        
Disaggregation of Revenue [Line Items]        
Revenues from Contracts with Customers 87 99 183 192
Other revenues not from contracts with customers 0 (1) 0 (1)
Operating revenues 87 98 183 191
Regulated Businesses | Operating Segments        
Disaggregation of Revenue [Line Items]        
Revenues from Contracts with Customers 1,263 1,173 2,370 2,214
Other revenues not from contracts with customers 5 5 9 13
Alternative revenue programs 4 4 6 10
Lease contract revenue 1 1 3 3
Operating revenues 1,268 1,178 2,379 2,227
Regulated Businesses | Water services: | Operating Segments        
Disaggregation of Revenue [Line Items]        
Revenues from Contracts with Customers 1,138 1,052 2,126 1,981
Other revenues not from contracts with customers 0 0 0 0
Operating revenues 1,138 1,052 2,126 1,981
Regulated Businesses | Wastewater services: | Operating Segments        
Disaggregation of Revenue [Line Items]        
Revenues from Contracts with Customers 113 107 220 208
Other revenues not from contracts with customers 0 0 0 0
Operating revenues 113 107 220 208
Regulated Businesses | Miscellaneous utility charges | Operating Segments        
Disaggregation of Revenue [Line Items]        
Revenues from Contracts with Customers 12 14 24 25
Other revenues not from contracts with customers 0 0 0 0
Operating revenues 12 14 24 25
Regulated Businesses | Residential | Water services: | Operating Segments        
Disaggregation of Revenue [Line Items]        
Revenues from Contracts with Customers 689 637 1,282 1,197
Other revenues not from contracts with customers 0 0 0 0
Operating revenues 689 637 1,282 1,197
Regulated Businesses | Residential | Wastewater services: | Operating Segments        
Disaggregation of Revenue [Line Items]        
Revenues from Contracts with Customers 74 71 148 139
Other revenues not from contracts with customers 0 0 0 0
Operating revenues 74 71 148 139
Regulated Businesses | Commercial | Water services: | Operating Segments        
Disaggregation of Revenue [Line Items]        
Revenues from Contracts with Customers 259 243 488 455
Other revenues not from contracts with customers 0 0 0 0
Operating revenues 259 243 488 455
Regulated Businesses | Commercial | Wastewater services: | Operating Segments        
Disaggregation of Revenue [Line Items]        
Revenues from Contracts with Customers 25 21 47 39
Other revenues not from contracts with customers 0 0 0 0
Operating revenues 25 21 47 39
Regulated Businesses | Fire service | Water services: | Operating Segments        
Disaggregation of Revenue [Line Items]        
Revenues from Contracts with Customers 49 48 97 93
Other revenues not from contracts with customers 0 0 0 0
Operating revenues 49 48 97 93
Regulated Businesses | Industrial | Water services: | Operating Segments        
Disaggregation of Revenue [Line Items]        
Revenues from Contracts with Customers 56 46 104 91
Other revenues not from contracts with customers 0 0 0 0
Operating revenues 56 46 104 91
Regulated Businesses | Industrial | Wastewater services: | Operating Segments        
Disaggregation of Revenue [Line Items]        
Revenues from Contracts with Customers 3 5 5 10
Other revenues not from contracts with customers 0 0 0 0
Operating revenues 3 5 5 10
Regulated Businesses | Public and other | Water services: | Operating Segments        
Disaggregation of Revenue [Line Items]        
Revenues from Contracts with Customers 85 78 155 145
Other revenues not from contracts with customers 0 0 0 0
Operating revenues 85 78 155 145
Regulated Businesses | Public and other | Wastewater services: | Operating Segments        
Disaggregation of Revenue [Line Items]        
Revenues from Contracts with Customers 11 10 20 20
Other revenues not from contracts with customers 0 0 0 0
Operating revenues $ 11 $ 10 $ 20 $ 20