Fair Value of Financial Instruments (Equity Investments) (Narrative) (Details) - USD ($)	6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Dec. 31, 2019
Fair Value, Financial Instruments Measured on a Non-Recurring Basis [Line Items]
Equity investments, adjusted cost basis, amount	$ 17,000,000		$ 18,000,000
Equity investments, carrying value	197,000,000		196,000,000
Equity investments, impairments	$ 0	$ 0
Waha JVs [Member]
Fair Value, Financial Instruments Measured on a Non-Recurring Basis [Line Items]
Equity method investment, ownership percentage	33.00%
Equity investments, carrying value	$ 157,000,000		$ 174,000,000
CCI [Member]
Fair Value, Financial Instruments Measured on a Non-Recurring Basis [Line Items]
Equity investments, adjusted cost basis, amount	$ 15,000,000