Revenue

3 Months Ended

Mar. 31, 2021

Revenue from Contract with Customer [Abstract]

Revenue

8. Revenue

The following table shows revenue disaggregated by operating area and product type:

	Successor
	Period from February 10, 2021 through March 31, 2021
	Oil		Natural Gas		NGL		Total
Appalachia	$	—	$	163	$	—	$	163
Gulf Coast	—		70		—		70
South Texas	117		28		19		164
Brazos Valley	89		15		4		108
Powder River Basin	28		14		6		48
Oil, natural gas and NGL revenue	$	234	$	290	$	29	$	553
Marketing revenue	$	162	$	97	$	18	$	277
	Predecessor
	Period from January 1, 2021 through February 9, 2021
	Oil		Natural Gas		NGL		Total
Appalachia	$	—	$	119	$	—	$	119
Gulf Coast	—		53		—		53
South Texas	92		15		15		122
Brazos Valley	67		2		2		71
Powder River Basin	20		7		6		33
Oil, natural gas and NGL revenue	$	179	$	196	$	23	$	398
Marketing revenue	$	141	$	78	$	20	$	239

	Predecessor
	Three Months Ended March 31, 2020
	Oil		Natural Gas		NGL		Total
Appalachia	$	—	$	175	$	—	$	175
Gulf Coast	—		85		—		85
South Texas	277		31		20		328
Brazos Valley	172		4		4		180
Powder River Basin	68		15		7		90
Mid-Continent	22		10		4		36
Oil, natural gas and NGL revenue	$	539	$	320	$	35	$	894
Marketing revenue from contracts with customers	$	508	$	124	$	30	$	662
Other marketing revenue	61		1		—		62
Marketing revenue	$	569	$	125	$	30	$	724

Accounts Receivable

Our accounts receivable are primarily from purchasers of oil, natural gas and NGL and from exploration and production companies that own interests in properties we operate. This industry concentration could affect our overall exposure to credit risk, either positively or negatively, because our purchasers and joint working interest owners may be similarly affected by changes in economic, industry or other conditions. We monitor the creditworthiness of all our counterparties and we generally require letters of credit or parent guarantees for receivables from parties deemed to have sub-standard credit, unless the credit risk can otherwise be mitigated. We estimate expected credit losses using forecasts based on historical information and current information, in addition to specifically identifying receivables that may be uncollectible.

Accounts receivable as of March 31, 2021 and December 31, 2020 are detailed below:

	Successor		Predecessor
	March 31, 2021		December 31, 2020
Oil, natural gas and NGL sales	$	575	$	589
Joint interest	93		119
Other	36		68
Allowance for doubtful accounts	—		(30)
Total accounts receivable, net	$	704	$	746