Price Risk Management Activities (Details) bu in Thousands, $ in Millions	3 Months Ended
	Mar. 31, 2019 USD ($) MBbls bu	Mar. 31, 2018 USD ($)
Price Risk Management Activities (Textual)
Compliance program costs | $	$ 21,978	$ 23,756
Environmental Compliance Program Price Risk [Member]
Price Risk Management Activities (Textual)
Compliance program costs | $	$ 91	$ 206
Economic Hedges [Member] | Future, 2019 Maturity [Member] | Long (Purchases) [Member] | Crude Oil and Refined Petroleum Products (in thousands of barrels) [Member]
Volume of Outstanding Contracts
Nonmonetary notional amount of price risk derivatives, volume	123,087
Economic Hedges [Member] | Future, 2019 Maturity [Member] | Long (Purchases) [Member] | Corn (in thousands of bushels) [Member]
Volume of Outstanding Contracts
Nonmonetary notional amount of price risk derivatives, volume | bu	19,005
Economic Hedges [Member] | Future, 2019 Maturity [Member] | Short (Sales) [Member] | Crude Oil and Refined Petroleum Products (in thousands of barrels) [Member]
Volume of Outstanding Contracts
Nonmonetary notional amount of price risk derivatives, volume	130,923
Economic Hedges [Member] | Future, 2019 Maturity [Member] | Short (Sales) [Member] | Corn (in thousands of bushels) [Member]
Volume of Outstanding Contracts
Nonmonetary notional amount of price risk derivatives, volume | bu	43,770
Economic Hedges [Member] | Future, 2020 Maturity [Member] | Long (Purchases) [Member] | Crude Oil and Refined Petroleum Products (in thousands of barrels) [Member]
Volume of Outstanding Contracts
Nonmonetary notional amount of price risk derivatives, volume	3,856
Economic Hedges [Member] | Future, 2020 Maturity [Member] | Long (Purchases) [Member] | Corn (in thousands of bushels) [Member]
Volume of Outstanding Contracts
Nonmonetary notional amount of price risk derivatives, volume | bu	1,275
Economic Hedges [Member] | Future, 2020 Maturity [Member] | Short (Sales) [Member] | Crude Oil and Refined Petroleum Products (in thousands of barrels) [Member]
Volume of Outstanding Contracts
Nonmonetary notional amount of price risk derivatives, volume	5,456
Economic Hedges [Member] | Future, 2020 Maturity [Member] | Short (Sales) [Member] | Corn (in thousands of bushels) [Member]
Volume of Outstanding Contracts
Nonmonetary notional amount of price risk derivatives, volume | bu	3,515
Economic Hedges [Member] | Options, 2019 Maturity [Member] | Long (Purchases) [Member] | Crude Oil and Refined Petroleum Products (in thousands of barrels) [Member]
Volume of Outstanding Contracts
Nonmonetary notional amount of price risk derivatives, volume	21,000
Economic Hedges [Member] | Options, 2019 Maturity [Member] | Short (Sales) [Member] | Crude Oil and Refined Petroleum Products (in thousands of barrels) [Member]
Volume of Outstanding Contracts
Nonmonetary notional amount of price risk derivatives, volume	21,000
Economic Hedges [Member] | Options, 2020 Maturity [Member] | Long (Purchases) [Member] | Crude Oil and Refined Petroleum Products (in thousands of barrels) [Member]
Volume of Outstanding Contracts
Nonmonetary notional amount of price risk derivatives, volume	0
Economic Hedges [Member] | Options, 2020 Maturity [Member] | Short (Sales) [Member] | Crude Oil and Refined Petroleum Products (in thousands of barrels) [Member]
Volume of Outstanding Contracts
Nonmonetary notional amount of price risk derivatives, volume	0
Economic Hedges [Member] | Physical Contracts, 2019 Maturity [Member] | Long (Purchases) [Member] | Corn (in thousands of bushels) [Member]
Volume of Outstanding Contracts
Nonmonetary notional amount of price risk derivatives, volume | bu	23,726
Economic Hedges [Member] | Physical Contracts, 2020 Maturity [Member] | Long (Purchases) [Member] | Corn (in thousands of bushels) [Member]
Volume of Outstanding Contracts
Nonmonetary notional amount of price risk derivatives, volume | bu	2,238
Economic Hedges [Member] | Foreign Exchange Contract, US Dollars [Member]
Price Risk Management Activities (Textual)
Monetary notional amount of derivative liabilities | $	$ 418
Economic Hedges [Member] | Foreign Exchange Contract, US Dollar Equivalent Canadian Dollars [Member]
Price Risk Management Activities (Textual)
Monetary notional amount of derivative liabilities | $	1,700
Economic Hedges [Member] | Foreign Exchange Contract, US Dollar Equivalent Pounds Sterling [Member]
Price Risk Management Activities (Textual)
Monetary notional amount of derivative liabilities | $	$ 300