Fair Value Measurements and Disclosures - Narrative (Details) - USD ($) $ in Millions	1 Months Ended		9 Months Ended
	Mar. 31, 2019	Jan. 31, 2019	Sep. 30, 2019	Sep. 30, 2018	Dec. 31, 2018
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Redeemable Noncontrolling Interest, Net	$ 97		$ 103		$ 0
Proceeds from issuance of preferred equity			97	$ 0
Noble Midstream
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Proceeds from issuance of preferred equity	100
Issuance costs of preferred equity	$ 3
Marcellus Shale Firm Transportation Agreement
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Firm transportation exit cost accrual		$ 92	$ 92	$ 0