Fair Value Measurement - Impairment (Details) $ in Millions	3 Months Ended
	Mar. 31, 2020 USD ($)	Mar. 31, 2019 USD ($)
Impaired Long-Lived Assets Held and Used [Line Items]
Property, Plant, and Equipment	$ 96
Goodwill	0
Assets	352
Property, plant, and equipment impairment	587
Goodwill, Impairment Loss	159
Asset Impairment	746	$ 0
Equity Method Investment, Other than Temporary Impairment	61
Equity Method Investments, Fair Value Disclosure	256
Total Impairment Charges, including Equity Method Investments	807
Permian Region [Member]
Impaired Long-Lived Assets Held and Used [Line Items]
Property, plant, and equipment impairment	461
South Region [Member]
Impaired Long-Lived Assets Held and Used [Line Items]
Property, plant, and equipment impairment	126
Level 1
Impaired Long-Lived Assets Held and Used [Line Items]
Property, Plant, and Equipment	0
Goodwill	0
Assets	0
Equity Method Investments, Fair Value Disclosure	0
Level 2
Impaired Long-Lived Assets Held and Used [Line Items]
Property, Plant, and Equipment	0
Goodwill	0
Assets	0
Equity Method Investments, Fair Value Disclosure	0
Level 3
Impaired Long-Lived Assets Held and Used [Line Items]
Property, Plant, and Equipment	96
Goodwill	0
Assets	352
Equity Method Investments, Fair Value Disclosure	$ 256
Level 3 | Valuation Technique, Discounted Cash Flow | Measurement Input, Discount Rate
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Assets, Measurement Input	14
Level 3 | Valuation Technique, Discounted Cash Flow | Measurement Input, Terminal Value Multiple
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Assets, Measurement Input	8
Level 3 | Arithmetic Average | Market Approach Valuation Technique | Measurement Input, EBITDA Multiple
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Goodwill, Measurement Input	8
Level 3 | Arithmetic Average | Oil | Valuation Technique, Discounted Cash Flow | Measurement Input, Commodity Future Price
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Assets, Measurement Input	55.98
Level 3 | Arithmetic Average | Natural Gas [Member] | Valuation Technique, Discounted Cash Flow | Measurement Input, Commodity Future Price
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Assets, Measurement Input	3.35
Level 3 | Arithmetic Average | Natural Gas Liquids | Valuation Technique, Discounted Cash Flow | Measurement Input, Commodity Future Price
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Assets, Measurement Input	0.52
Level 3 | Minimum | Market Approach Valuation Technique | Measurement Input, EBITDA Multiple
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Goodwill, Measurement Input	5.2
Level 3 | Minimum | Oil | Valuation Technique, Discounted Cash Flow | Measurement Input, Commodity Future Price
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Assets, Measurement Input	34.52
Level 3 | Minimum | Natural Gas [Member] | Valuation Technique, Discounted Cash Flow | Measurement Input, Commodity Future Price
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Assets, Measurement Input	2.28
Level 3 | Minimum | Natural Gas Liquids | Valuation Technique, Discounted Cash Flow | Measurement Input, Commodity Future Price
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Assets, Measurement Input	0.30
Level 3 | Maximum | Market Approach Valuation Technique | Measurement Input, EBITDA Multiple
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Goodwill, Measurement Input	16.5
Level 3 | Maximum | Oil | Valuation Technique, Discounted Cash Flow | Measurement Input, Commodity Future Price
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Assets, Measurement Input	67.61
Level 3 | Maximum | Natural Gas [Member] | Valuation Technique, Discounted Cash Flow | Measurement Input, Commodity Future Price
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Assets, Measurement Input	4.12
Level 3 | Maximum | Natural Gas Liquids | Valuation Technique, Discounted Cash Flow | Measurement Input, Commodity Future Price
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Assets, Measurement Input	0.62