Risk Management - Effect on Income Statement Not Designated (Details) - Energy commodity derivative contracts - USD ($) $ in Millions	3 Months Ended	6 Months Ended
Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Derivative [Line Items]
Gain/(loss) recognized in income on derivatives	$ 151	$ 15	$ 272	$ 23
Revenues-Commodity sales
Derivative [Line Items]
Gain/(loss) recognized in income on derivatives	149	14	266	24
Cost of sales
Derivative [Line Items]
Gain/(loss) recognized in income on derivatives	2	(1)	6	(3)
Earnings from equity investments
Derivative [Line Items]
Gain/(loss) recognized in income on derivatives	0	2	0	2
Derivatives not designated as hedging instruments
Derivative [Line Items]
Gain/(loss) on settlement of derivative contracts	$ 179	$ (6)	$ 253	$ (2)

Amount of realized and unrealized gain (loss) of derivative instruments not designated or qualifying as hedging instruments.

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-Publisher FASB
-Name Accounting Standards Codification
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