Income Taxes Income Taxes - Narrative (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	[1]	Feb. 01, 2019
Business Acquisition [Line Items]
Effective income tax rate	0.00%
Income tax benefit	$ 314	$ 0
Wildhorse Resource Development Corporation
Business Acquisition [Line Items]
Deferred tax liabilities				$ 314
Income tax benefit	314
Deferred tax liability, plant, property and equipment and prepaid compensation				401
Deferred tax assets, operating loss carryforward, limitations	$ 61
Wildhorse Resource Development Corporation | Federal
Business Acquisition [Line Items]
Deferred tax asset, operating loss carryforward				$ 87

[1] Financial information for 2018 has been recast to reflect the retrospective application of the successful efforts method of accounting. See Note 1.