General - Narrative (Details) - USD ($) shares in Millions, $ in Millions	3 Months Ended
	Mar. 31, 2021	Dec. 31, 2020
WES Midstream segment
Summary of Significant Accounting Policies [Line Items]
Non-voting general partner interest	2.00%
Limited partner interest	49.10%
Non-voting limited partner interest	2.00%
Effective economic interest	51.20%
Discontinued Operations, Held-for-sale | Ghana Operations
Summary of Significant Accounting Policies [Line Items]
Loss from discontinued operations	$ 42
Property, plant and equipment, net	1,200	$ 1,400
Deferred income taxes, asset retirement obligations and finance lease liability	$ 607	$ 670
Disposed of by Sale, Not Discontinued Operations | WES Midstream segment
Summary of Significant Accounting Policies [Line Items]
Number of limited partner units sold (in units)	11.5
Proceeds from sale of limited partner units	$ 200
Gain on sale	102
Discontinued Operations | Ecuador Operations
Summary of Significant Accounting Policies [Line Items]
Loss from discontinued operations	$ 403