The following table presents a summary of Devon’s asset impairments. Unproved impairments shown below are included in exploration expenses in the consolidated statements of comprehensive earnings.

	Three Months Ended March 31,
	2020		2019
Proved oil and gas assets	$	2,664	$	—
Other assets		2		—
Total asset impairments	$	2,666	$	—

Unproved impairments	$	110	$	1

Reduced demand from the COVID-19 pandemic caused an unprecedented downturn in the price of oil. As a result, Devon reduced planned 2020 capital investment by 45%. With materially lower commodity prices and reduced near-term investment, Devon assessed all of its oil and gas fields for impairment as of March 31, 2020. For impairment determinations, Devon historically utilized NYMEX forward strip prices for the first five years and applied internally generated price forecasts for subsequent years. In response to the COVID-19 pandemic, the NYMEX forward market became highly illiquid as evidenced by materially reduced trading volumes for periods beyond 2021. Therefore, Devon supplemented the NYMEX forward strip prices with price forecasts published by reputable investment banks and reservoir engineering firms to estimate future revenues as of March 31, 2020. To measure indicated impairments, Devon used a market-based weighted-average cost of capital to discount the future net cash flows.

Devon recognized approximately $2.7 billion of proved asset impairments during the first three months of 2020. These impairments related to the Anadarko Basin and Rockies fields in which the cost basis included acquisitions completed in 2016 and 2015, respectively, when commodity prices were much higher than they are today. In the first quarter of 2020, Devon recognized $2 million of product line fill impairments.

Due to the recent downturn in the commodity price environment and reduced near-term investment as discussed above, Devon also recognized $110 million of unproved impairments during the first three months of 2020, primarily in the Rockies field. During the first three months of 2019, Devon allowed certain non-core acreage to expire without plans for development resulting in unproved impairments of $1 million.