THE ACQUISITION - NARRATIVE (Details) - USD ($)		5 Months Ended	12 Months Ended
	Aug. 08, 2019	Dec. 31, 2019	Dec. 31, 2019	Aug. 07, 2019
WES
Business Acquisition [Line Items]
Limited partner interest			55.40%
WES | WES | Public Ownership
Business Acquisition [Line Items]
Limited partner interest			44.60%
Revolving Credit Facility
Business Acquisition [Line Items]
Revolving credit facility, maximum borrowing capacity				$ 3,000,000,000.0
Anadarko Petroleum Corporation
Business Acquisition [Line Items]
Cash of acquirer in exchange for acquiree (usd per share)	$ 59.00
Exchange ratio (per share of Anadarko common stock)	0.2934
Closing price per share, common stock (usd per share)	$ 46.31
Debt instrument issued	$ 21,800,000,000
Amount from exercise of warrants	10,000,000,000
Assumed debt	13,240,000,000
Property, plant and equipment	49,074,000,000
Revenues from date of merger		$ 4,200,000,000
Net loss attributable to common shareholders from date of merger		1,700,000,000
Anadarko Petroleum Corporation | Proved gas and oil properties
Business Acquisition [Line Items]
Property, plant and equipment	19,100,000,000
Anadarko Petroleum Corporation | Unproved Properties
Business Acquisition [Line Items]
Property, plant and equipment	27,400,000,000
Anadarko Petroleum Corporation | Land, Mineral Interests And Corporate Properties
Business Acquisition [Line Items]
Property, plant and equipment	$ 2,500,000,000
Anadarko Petroleum Corporation | Customer Relationships
Business Acquisition [Line Items]
Amortization period	30 years
Anadarko Petroleum Corporation | Level 2
Business Acquisition [Line Items]
Assumed debt	$ 2,500,000,000
Anadarko Petroleum Corporation | WES
Business Acquisition [Line Items]
Assumed debt	7,407,000,000
Property, plant and equipment	10,160,000,000
Anadarko Petroleum Corporation | WES | Level 2
Business Acquisition [Line Items]
Assumed debt	730,000,000
Anadarko Petroleum Corporation | WES
Business Acquisition [Line Items]
Revenues from date of merger		$ 1,100,000,000
Anadarko Petroleum Corporation | Revolving Credit Facility
Business Acquisition [Line Items]
Revolving credit facility, additional commitment	$ 2,000,000,000.0
Anadarko Petroleum Corporation | Series A Preferred Stock
Business Acquisition [Line Items]
Shares issued (in shares)	100,000
Anadarko Petroleum Corporation | Common Stock
Business Acquisition [Line Items]
Closing price per share, common stock (usd per share)	$ 46.31
Shares issued (in shares)	144,000,000
Number of securities called by warrant (in shares)	80,000,000
Exercise price of warrant (usd per share)	$ 62.50
Anadarko Petroleum Corporation | Senior notes
Business Acquisition [Line Items]
Debt instrument issued	$ 13,000,000,000.0
Anadarko Petroleum Corporation | Secured Debt
Business Acquisition [Line Items]
Debt instrument issued	$ 8,800,000,000