Property, Plant and Equipment - Schedule of Major Classes (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Public Utility, Property, Plant and Equipment [Line Items]
Construction work in progress	$ 1,040	$ 974
Other plant	24	23
Total utility plant	32,050	29,627
Nonutility property	139	109
Total property, plant and equipment	32,189	29,736
Utility Plant | Land and other non-depreciable assets
Public Utility, Property, Plant and Equipment [Line Items]
Utility plant excluding Construction work in progress	293	239
Utility Plant | Sources of supply
Public Utility, Property, Plant and Equipment [Line Items]
Utility plant excluding Construction work in progress	$ 1,081	1,003
Weighted Average Useful Life	46 years
Utility Plant | Sources of supply | Minimum
Public Utility, Property, Plant and Equipment [Line Items]
Range of Remaining Useful Lives	10 years
Utility Plant | Sources of supply | Maximum
Public Utility, Property, Plant and Equipment [Line Items]
Range of Remaining Useful Lives	127 years
Utility Plant | Treatment and pumping facilities
Public Utility, Property, Plant and Equipment [Line Items]
Utility plant excluding Construction work in progress	$ 4,594	4,298
Weighted Average Useful Life	39 years
Utility Plant | Treatment and pumping facilities | Minimum
Public Utility, Property, Plant and Equipment [Line Items]
Range of Remaining Useful Lives	3 years
Utility Plant | Treatment and pumping facilities | Maximum
Public Utility, Property, Plant and Equipment [Line Items]
Range of Remaining Useful Lives	101 years
Utility Plant | Transmission and distribution facilities
Public Utility, Property, Plant and Equipment [Line Items]
Utility plant excluding Construction work in progress	$ 13,900	12,971
Weighted Average Useful Life	68 years
Utility Plant | Transmission and distribution facilities | Minimum
Public Utility, Property, Plant and Equipment [Line Items]
Range of Remaining Useful Lives	6 years
Utility Plant | Transmission and distribution facilities | Maximum
Public Utility, Property, Plant and Equipment [Line Items]
Range of Remaining Useful Lives	128 years
Utility Plant | Services, meters and fire hydrants
Public Utility, Property, Plant and Equipment [Line Items]
Utility plant excluding Construction work in progress	$ 5,696	5,162
Weighted Average Useful Life	32 years
Utility Plant | Services, meters and fire hydrants | Minimum
Public Utility, Property, Plant and Equipment [Line Items]
Range of Remaining Useful Lives	5 years
Utility Plant | Services, meters and fire hydrants | Maximum
Public Utility, Property, Plant and Equipment [Line Items]
Range of Remaining Useful Lives	90 years
Utility Plant | General structures and equipment
Public Utility, Property, Plant and Equipment [Line Items]
Utility plant excluding Construction work in progress	$ 2,512	2,289
Weighted Average Useful Life	16 years
Utility Plant | General structures and equipment | Minimum
Public Utility, Property, Plant and Equipment [Line Items]
Range of Remaining Useful Lives	1 year
Utility Plant | General structures and equipment | Maximum
Public Utility, Property, Plant and Equipment [Line Items]
Range of Remaining Useful Lives	109 years
Utility Plant | Waste collection
Public Utility, Property, Plant and Equipment [Line Items]
Utility plant excluding Construction work in progress	$ 1,719	1,539
Weighted Average Useful Life	57 years
Utility Plant | Waste collection | Minimum
Public Utility, Property, Plant and Equipment [Line Items]
Range of Remaining Useful Lives	5 years
Utility Plant | Waste collection | Maximum
Public Utility, Property, Plant and Equipment [Line Items]
Range of Remaining Useful Lives	113 years
Utility Plant | Waste treatment, pumping and disposal
Public Utility, Property, Plant and Equipment [Line Items]
Utility plant excluding Construction work in progress	$ 1,191	$ 1,129
Weighted Average Useful Life	37 years
Utility Plant | Waste treatment, pumping and disposal | Minimum
Public Utility, Property, Plant and Equipment [Line Items]
Range of Remaining Useful Lives	2 years
Utility Plant | Waste treatment, pumping and disposal | Maximum
Public Utility, Property, Plant and Equipment [Line Items]
Range of Remaining Useful Lives	153 years
Nonutility Plant
Public Utility, Property, Plant and Equipment [Line Items]
Weighted Average Useful Life	12 years
Nonutility Plant | Minimum
Public Utility, Property, Plant and Equipment [Line Items]
Range of Remaining Useful Lives	3 years
Nonutility Plant | Maximum
Public Utility, Property, Plant and Equipment [Line Items]
Range of Remaining Useful Lives	50 years