General - Narrative (Details) - USD ($) shares in Millions, $ in Millions	1 Months Ended		3 Months Ended			9 Months Ended
	Oct. 31, 2021	Mar. 31, 2021	Sep. 30, 2021	Mar. 31, 2021	Sep. 30, 2020	Sep. 30, 2021	Dec. 31, 2020
Summary of Significant Accounting Policies [Line Items]
Equity method investment amounts			$ 3,266			$ 3,266	$ 3,250
WES Midstream segment
Summary of Significant Accounting Policies [Line Items]
Impairment of equity method investment					$ 2,700
Equity method investment amounts					$ 1,900
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, Held-for-sale | Ghana Operations
Summary of Significant Accounting Policies [Line Items]
Income (loss) from discontinued operations			3			(32)
Property, plant and equipment, net			1,000			1,000	1,400
Deferred income taxes, asset retirement obligations and finance lease liability			$ 550			$ 550	$ 670
Discontinued Operations, Held-for-sale | Ghana Operations | Subsequent Event
Summary of Significant Accounting Policies [Line Items]
Agreement consideration	$ 750
Net proceeds from sale	555
Settlement of certain tax claims	$ 170
Discontinued Operations | Ecuador Operations
Summary of Significant Accounting Policies [Line Items]
Income (loss) from discontinued operations				$ (403)
WES Midstream segment
Summary of Significant Accounting Policies [Line Items]
Non-voting general partner interest						2.00%
Limited partner interest						49.60%
Non-voting limited partner interest						2.00%
Effective economic interest						51.70%