Impairment Expense (Details) - USD ($) $ in Millions		3 Months Ended	12 Months Ended
		Dec. 31, 2021	Dec. 31, 2021		Dec. 31, 2020		Dec. 31, 2019
Impairment of Oil and Gas Properties [Line Items]
Impairment of Oil and Gas Properties			$ 376		$ 2,100		$ 518
Proved Properties
Impairment of Oil and Gas Properties [Line Items]
Impairment of Oil and Gas Properties	[1]		20		1,268		207
Unproved Properties
Impairment of Oil and Gas Properties [Line Items]
Impairment of Oil and Gas Properties		$ 38	310	[2]	472	[2]	220	[2]
Leasehold Costs of Impairments of Unproved Oil and Gas Properties					252
Other Assets
Impairment of Oil and Gas Properties [Line Items]
Other Assets Impairments Related to Commodity Price-Related Write-Down					72		90
Impairment of Oil and Gas Properties	[3]		28		300		91
Impairments for Owned and Leased Sand and Crude-by-Rail Assets					228
Inventories
Impairment of Oil and Gas Properties [Line Items]
Impairment of Oil and Gas Properties			13		0		0
Firm Commitments Contracts
Impairment of Oil and Gas Properties [Line Items]
Impairment of Oil and Gas Properties			$ 5	[4]	60		$ 0
Canadian Firm Commitment Contracts					$ 60

[1] Impairments to proved oil and gas properties in 2020 included legacy and non-core natural gas and crude oil and combo plays. Impairments to proved oil and gas properties in 2019 included domestic legacy natural gas assets. See Notes 1 and 13.

[2] Unproved properties with acquisition costs that are not individually significant are aggregated, and the portion of such costs estimated to be nonproductive is amortized over the remaining lease term. Unproved properties with individually significant acquisition costs are reviewed individually for impairment. Impairments of unproved oil and gas properties included $38 million in 2021 for the decision in the fourth quarter of 2021 to exit Block 36 and Block 49 in Oman. Impairments of unproved oil and gas properties included charges of $252 million in 2020 for certain leasehold costs that are no longer expected to be developed before expiration in the United States. See Note 1.

[3] Includes impairment charges for owned and leased sand and crude-by-rail assets of $228 million in 2020 (see Note 18) and a commodity price-related write-down of other assets of $72 million and $90 million in 2020 and 2019, respectively (see Note 13).

[4] Includes impairment charges of $60 million in 2020 for firm commitment contracts related to its decision to exit the Horn River Basin in British Columbia, Canada.