Organization and Summary of Significant Accounting Policies (Summary of Other Property and Equipment) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Property, Plant and Equipment [Line Items]
Less: Accumulated depreciation and impairment	$ (311)	$ (300)
Total	212	220
Water facilities
Property, Plant and Equipment [Line Items]
Other property and equipment gross	$ 228	217
Water facilities | Minimum
Property, Plant and Equipment [Line Items]
Long lived assets, useful life	5 years
Water facilities | Maximum
Property, Plant and Equipment [Line Items]
Long lived assets, useful life	10 years
Gathering systems
Property, Plant and Equipment [Line Items]
Other property and equipment gross	$ 54	32
Gathering systems | Minimum
Property, Plant and Equipment [Line Items]
Long lived assets, useful life	15 years
Gathering systems | Maximum
Property, Plant and Equipment [Line Items]
Long lived assets, useful life	25 years
Technology infrastructure
Property, Plant and Equipment [Line Items]
Other property and equipment gross	$ 133	154
Technology infrastructure | Minimum
Property, Plant and Equipment [Line Items]
Long lived assets, useful life	3 years
Technology infrastructure | Maximum
Property, Plant and Equipment [Line Items]
Long lived assets, useful life	7 years
Drilling rigs and equipment
Property, Plant and Equipment [Line Items]
Long lived assets, useful life	3 years
Other property and equipment gross	$ 26	32
Land, buildings and leasehold improvements
Property, Plant and Equipment [Line Items]
Other property and equipment gross	$ 41	41
Land, buildings and leasehold improvements | Minimum
Property, Plant and Equipment [Line Items]
Long lived assets, useful life	10 years
Land, buildings and leasehold improvements | Maximum
Property, Plant and Equipment [Line Items]
Long lived assets, useful life	30 years
Other
Property, Plant and Equipment [Line Items]
Other property and equipment gross	$ 41	$ 44