Impairments (Tables)

12 Months Ended

Dec. 31, 2019

Asset Impairment Charges [Abstract]

Summary of impairments

A summary of our impairments of oil and natural gas properties for the years ended December 31, 2019, 2018 and 2017 is as follows:

	Years Ended December 31,
	2019		2018		2017
	($ in millions)
Impairments due to lower forecasted commodity prices	$	8	$	23	$	27
Impairments due to reduction in future development(a)	—		—		560
Impairments due to anticipated sale	—		55		222
Total impairments of oil and natural gas properties	$	8	$	78	$	809

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(a)    The impairment was the result of an updated development plan in 2017, which included a removal of PUDs from properties in the process of being divested in the Mid-Continent operating area.

A summary of our impairments of fixed assets by asset class and other charges for the years ended December 31, 2019, 2018 and 2017 is as follows:

	Years Ended December 31,
	2019		2018		2017
	($ in millions)
Natural gas compressors(a)	$	—	$	45	$	—
Buildings and land	1		4		5
Other	2		4		—
Total impairments of fixed assets and other	$	3	$	53	$	5