Credit Losses (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Accounts Receivable, Allowance for Credit Loss	$ 11
Accounts Receivable, Credit Loss Expense (Reversal)	8
Accounts Receivable, Allowance for Credit Loss	30
Accounts Receivable, Allowance for Credit Loss, Recovery	(1)
Cumulative Effect, Period of Adoption, Adjustment [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Accounts Receivable, Allowance for Credit Loss	$ 12
Trade Accounts Receivable [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Accounts Receivable, Credit Loss Expense (Reversal)		$ 2
Joint Interest Billing [JIB] Receivables [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Accounts Receivable, Credit Loss Expense (Reversal)		$ 6