Impairment Expense

12 Months Ended

Dec. 31, 2022

Impairment expense was as follows for the years ended December 31, 2022, 2021 and 2020 (in millions):


	2022		2021		2020

Proved properties (1)	$	120	$	20	$	1,268
Unproved properties (2)	206		310		472
Other assets (3)	29		28		300
Inventories	25		13		—
Firm commitment contracts (4)	2		5		60
Total	$	382	$	376	$	2,100

(1) Impairments to proved oil and gas properties in 2020 included legacy and non-core natural gas and crude oil and combo plays. 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 in 2020 (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.