Derivatives and Risk Management Activities - Offsetting Asset and Liabilities (Details) - USD ($) $ in Millions	Mar. 31, 2020	Dec. 31, 2019
Derivative Asset Positions
Effect of Collateral Netting	$ (125)	$ (45)
Commodity Derivatives
Effect of Collateral Netting
Net Carrying Value Presented on the Balance Sheet, Total	127	85
Derivative Asset Positions
Effect of Collateral Netting	(125)	(45)
Derivative Liability Positions
Gross Position - Asset	706	235
Gross Position - Liability	(454)	(105)
Other current assets | Commodity Derivatives
Derivative Asset Positions
Gross Position - Asset	446	179
Gross Position - Liability	(256)	(37)
Effect of Collateral Netting	(125)	(45)
Net Carrying Value Presented on the Balance Sheet	65	97
Other long-term assets, net | Commodity Derivatives
Derivative Asset Positions
Gross Position - Asset	99	24
Gross Position - Liability	(15)
Net Carrying Value Presented on the Balance Sheet	84	24
Other current liabilities | Commodity Derivatives
Derivative Liability Positions
Gross Position - Asset	161	32
Gross Position - Liability	(171)	(56)
Net Carrying Value Presented on the Balance Sheet	(10)	(24)
Other long-term liabilities and deferred credits | Commodity Derivatives
Derivative Liability Positions
Gross Position - Liability	(12)	(12)
Net Carrying Value Presented on the Balance Sheet	$ (12)	$ (12)