v3.26.3
Revenue Recognition - Disaggregated Revenues (Details) - USD ($)
$ in Millions
 3 Months Ended 9 Months Ended
Sep. 30, 2026
Sep. 30, 2025
Sep. 30, 2026
Sep. 30, 2025
Disaggregation of Revenue [Line Items]        
Revenues from Contracts with Customers $ 1,502 $ 1,454 $ 4,055 $ 3,855
Other revenues not from contracts with customers 8 (3) 17 14
Operating revenues 1,510 1,451 4,072 3,869
Operating Segments | Regulated Businesses        
Disaggregation of Revenue [Line Items]        
Revenues from Contracts with Customers 1,395 1,346 3,765 3,555
Other revenues not from contracts with customers 8 (3) 17 15
Operating revenues 1,403 1,343 3,782 3,570
Alternative revenue programs 7 (4) 13 11
Lease contract revenue 1 1 4 4
Operating Segments | Water Services | Regulated Businesses        
Disaggregation of Revenue [Line Items]        
Revenues from Contracts with Customers 1,263 1,220 3,389 3,201
Other revenues not from contracts with customers 0 0 0 0
Operating revenues 1,263 1,220 3,389 3,201
Operating Segments | Wastewater Services | Regulated Businesses        
Disaggregation of Revenue [Line Items]        
Revenues from Contracts with Customers 120 113 340 316
Other revenues not from contracts with customers 0 0 0 0
Operating revenues 120 113 340 316
Operating Segments | Miscellaneous utility charges | Regulated Businesses        
Disaggregation of Revenue [Line Items]        
Revenues from Contracts with Customers 12 13 36 38
Other revenues not from contracts with customers 0 0 0 0
Operating revenues 12 13 36 38
Operating Segments | Residential | Water Services | Regulated Businesses        
Disaggregation of Revenue [Line Items]        
Revenues from Contracts with Customers 762 739 2,044 1,936
Other revenues not from contracts with customers 0 0 0 0
Operating revenues 762 739 2,044 1,936
Operating Segments | Residential | Wastewater Services | Regulated Businesses        
Disaggregation of Revenue [Line Items]        
Revenues from Contracts with Customers 81 75 229 214
Other revenues not from contracts with customers 0 0 0 0
Operating revenues 81 75 229 214
Operating Segments | Commercial | Water Services | Regulated Businesses        
Disaggregation of Revenue [Line Items]        
Revenues from Contracts with Customers 297 287 785 742
Other revenues not from contracts with customers 0 0 0 0
Operating revenues 297 287 785 742
Operating Segments | Commercial | Wastewater Services | Regulated Businesses        
Disaggregation of Revenue [Line Items]        
Revenues from Contracts with Customers 26 25 73 64
Other revenues not from contracts with customers 0 0 0 0
Operating revenues 26 25 73 64
Operating Segments | Fire service | Water Services | Regulated Businesses        
Disaggregation of Revenue [Line Items]        
Revenues from Contracts with Customers 49 46 146 139
Other revenues not from contracts with customers 0 0 0 0
Operating revenues 49 46 146 139
Operating Segments | Industrial | Water Services | Regulated Businesses        
Disaggregation of Revenue [Line Items]        
Revenues from Contracts with Customers 60 55 164 146
Other revenues not from contracts with customers 0 0 0 0
Operating revenues 60 55 164 146
Operating Segments | Industrial | Wastewater Services | Regulated Businesses        
Disaggregation of Revenue [Line Items]        
Revenues from Contracts with Customers 3 7 8 17
Other revenues not from contracts with customers 0 0 0 0
Operating revenues 3 7 8 17
Operating Segments | Public and other | Water Services | Regulated Businesses        
Disaggregation of Revenue [Line Items]        
Revenues from Contracts with Customers 95 93 250 238
Other revenues not from contracts with customers 0 0 0
Operating revenues 95 93 250 238
Operating Segments | Public and other | Wastewater Services | Regulated Businesses        
Disaggregation of Revenue [Line Items]        
Revenues from Contracts with Customers 10 6 30 21
Other revenues not from contracts with customers 0 0 0
Operating revenues 10 6 30 21
Other        
Disaggregation of Revenue [Line Items]        
Revenues from Contracts with Customers 107 108 290 300
Other revenues not from contracts with customers 0 0 0 (1)
Operating revenues $ 107 $ 108 $ 290 $ 299