Asset Acquisitions and Dispositions (Non-Recurring Restructuring and Transition-Related Costs) (Details) - Concho Resources Incorporated [Member] - USD ($) $ in Millions	3 Months Ended	12 Months Ended
	Mar. 31, 2021	Dec. 31, 2021
Business Acquisition [Line Items]
Transaction Cost	$ 157	$ 157
Restructuring Cost		234
Total Cost		391
Production and operating expenses [Member]
Business Acquisition [Line Items]
Restructuring Cost		128
Total Cost		128
Selling, general and administrative expenses [Member]
Business Acquisition [Line Items]
Transaction Cost		135
Restructuring Cost		67
Total Cost		202
Exploration expenses [Member]
Business Acquisition [Line Items]
Transaction Cost		18
Restructuring Cost		8
Total Cost		26
Taxes other than income taxes [Member]
Business Acquisition [Line Items]
Transaction Cost		4
Restructuring Cost		2
Total Cost		6
Other expenses [Member]
Business Acquisition [Line Items]
Transaction Cost		0
Restructuring Cost		29
Total Cost		$ 29