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The increase (decrease) during the reporting period in the assets (liabilities) created through trading commodity-based derivative instruments.

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Derivative and Financial Instruments - Commodity Gain (Loss) (Details) - USD ($) $ in Millions	3 Months Ended
	Jun. 30, 2021	Mar. 31, 2021	Mar. 31, 2020	Jan. 15, 2021
Concho Resources Inc [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Increase (Decrease) in Commodity Contract Assets and Liabilities		$ 692
Commodity Contract [Member] \| Concho Resources Inc [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Gains (losses) from commodity derivatives		(305)
Derivative, Fair Value, Net				$ 456
Increase (Decrease) in Commodity Contract Assets and Liabilities		692
Accelerated contracts [Member] \| Concho Resources Inc [Member] \| Subsequent Event [Member] \| Scenario, Plan [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Increase (Decrease) in Commodity Contract Assets and Liabilities	$ 69
Sales and other operating revenues [Member] \| Commodity Contract [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Gains (losses) from commodity derivatives		(279)	$ 47
Sales and other operating revenues [Member] \| Commodity Contract [Member] \| Concho Resources Inc [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Gains (losses) from commodity derivatives		(173)
Sales and other operating revenues [Member] \| Accelerated contracts [Member] \| Concho Resources Inc [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Gains (losses) from commodity derivatives		(132)
Other Income [Member] \| Commodity Contract [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Gains (losses) from commodity derivatives		17	2
Purchased commodities [Member] \| Commodity Contract [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Gains (losses) from commodity derivatives		$ 13	$ (27)