v3.25.1
Revenue Recognition - Disaggregated Revenues (Details) - USD ($)
$ in Millions
 3 Months Ended
Mar. 31, 2025
Mar. 31, 2024
Disaggregation of Revenue [Line Items]    
Revenues from Contracts with Customers $ 1,134 $ 1,003
Other revenues not from contracts with customers 8 8
Operating revenues 1,142 1,011
Other    
Disaggregation of Revenue [Line Items]    
Revenues from Contracts with Customers 93 83
Other revenues not from contracts with customers 0 0
Operating revenues 93 83
Regulated Businesses | Operating Segments    
Disaggregation of Revenue [Line Items]    
Revenues from Contracts with Customers 1,041 920
Alternative revenue programs 6 2
Lease contract revenue 2 2
Other revenues not from contracts with customers 8 8
Operating revenues 1,049 928
Regulated Businesses | Water Services | Operating Segments    
Disaggregation of Revenue [Line Items]    
Revenues from Contracts with Customers 929 826
Other revenues not from contracts with customers 0 4
Operating revenues 929 830
Regulated Businesses | Wastewater Services | Operating Segments    
Disaggregation of Revenue [Line Items]    
Revenues from Contracts with Customers 101 85
Other revenues not from contracts with customers 0  
Operating revenues 101 85
Regulated Businesses | Miscellaneous Utility Charge | Operating Segments    
Disaggregation of Revenue [Line Items]    
Revenues from Contracts with Customers 11 9
Operating revenues 11 9
Regulated Businesses | Residential | Water Services | Operating Segments    
Disaggregation of Revenue [Line Items]    
Revenues from Contracts with Customers 560 502
Other revenues not from contracts with customers 0 2
Operating revenues 560 504
Regulated Businesses | Residential | Wastewater Services | Operating Segments    
Disaggregation of Revenue [Line Items]    
Revenues from Contracts with Customers 68 59
Other revenues not from contracts with customers 0  
Operating revenues 68 59
Regulated Businesses | Commercial | Water Services | Operating Segments    
Disaggregation of Revenue [Line Items]    
Revenues from Contracts with Customers 212 186
Other revenues not from contracts with customers 0 1
Operating revenues 212 187
Regulated Businesses | Commercial | Wastewater Services | Operating Segments    
Disaggregation of Revenue [Line Items]    
Revenues from Contracts with Customers 18 16
Operating revenues 18 16
Regulated Businesses | Fire service | Water Services | Operating Segments    
Disaggregation of Revenue [Line Items]    
Revenues from Contracts with Customers 45 41
Operating revenues 45 41
Regulated Businesses | Industrial | Water Services | Operating Segments    
Disaggregation of Revenue [Line Items]    
Revenues from Contracts with Customers 45 42
Other revenues not from contracts with customers 0  
Operating revenues 45 42
Regulated Businesses | Industrial | Wastewater Services | Operating Segments    
Disaggregation of Revenue [Line Items]    
Revenues from Contracts with Customers 5 2
Operating revenues 5 2
Regulated Businesses | Public and other | Water Services | Operating Segments    
Disaggregation of Revenue [Line Items]    
Revenues from Contracts with Customers 67 55
Other revenues not from contracts with customers 0 1
Operating revenues 67 56
Regulated Businesses | Public and other | Wastewater Services | Operating Segments    
Disaggregation of Revenue [Line Items]    
Revenues from Contracts with Customers 10 8
Operating revenues $ 10 $ 8