Price Risk Management Activities (Details) lb in Thousands, bu in Thousands, MMBTU in Thousands, $ in Millions	1 Months Ended	12 Months Ended
	Jan. 31, 2016 USD ($)	Dec. 31, 2015 USD ($) MMBTU lb MBbls bu	Dec. 31, 2014 USD ($)	Dec. 31, 2013 USD ($)
Price Risk Management Activities (Textual)
Compliance program costs | $		$ 440	$ 372	$ 517
Foreign Currency Contract [Member]
Price Risk Management Activities (Textual)
Monetary notional amount of derivative liabilities | $		$ 292
Foreign currency commitments maturity date		Jan. 31, 2016
Foreign Currency Contract [Member] | Subsequent Event [Member]
Price Risk Management Activities (Textual)
Gain (loss) recognized in income on derivatives | $	$ 10
Fair Value Hedging [Member]
Volume of Outstanding Contracts
Nonmonetary notional amount of price risk derivatives, volume		0
Cash Flow Hedging [Member]
Volume of Outstanding Contracts
Nonmonetary notional amount of price risk derivatives, volume		0
Economic Hedging [Member] | Swap, Maturity Year Two [Member] | Long (Purchases) [Member] | Crude Oil (in thousands of barrels) [Member]
Volume of Outstanding Contracts
Nonmonetary notional amount of price risk derivatives, volume		11,727
Economic Hedging [Member] | Swap, Maturity Year Two [Member] | Short (Sales) [Member] | Crude Oil (in thousands of barrels) [Member]
Volume of Outstanding Contracts
Nonmonetary notional amount of price risk derivatives, volume		11,559
Economic Hedging [Member] | Swap, Maturity Year Three [Member] | Long (Purchases) [Member] | Crude Oil (in thousands of barrels) [Member]
Volume of Outstanding Contracts
Nonmonetary notional amount of price risk derivatives, volume		0
Economic Hedging [Member] | Swap, Maturity Year Three [Member] | Short (Sales) [Member] | Crude Oil (in thousands of barrels) [Member]
Volume of Outstanding Contracts
Nonmonetary notional amount of price risk derivatives, volume		0
Economic Hedging [Member] | Future, Maturity Year Two [Member] | Long (Purchases) [Member] | Crude Oil (in thousands of barrels) [Member]
Volume of Outstanding Contracts
Nonmonetary notional amount of price risk derivatives, volume		73,746
Economic Hedging [Member] | Future, Maturity Year Two [Member] | Long (Purchases) [Member] | Grain (in bushels) [Member]
Volume of Outstanding Contracts
Nonmonetary notional amount of price risk derivatives, volume | bu		19,345
Economic Hedging [Member] | Future, Maturity Year Two [Member] | Long (Purchases) [Member] | Soybean Oil (in pounds) [Member]
Volume of Outstanding Contracts
Nonmonetary notional amount of price risk derivatives, mass | lb		83,340
Economic Hedging [Member] | Future, Maturity Year Two [Member] | Short (Sales) [Member] | Crude Oil (in thousands of barrels) [Member]
Volume of Outstanding Contracts
Nonmonetary notional amount of price risk derivatives, volume		85,999
Economic Hedging [Member] | Future, Maturity Year Two [Member] | Short (Sales) [Member] | Grain (in bushels) [Member]
Volume of Outstanding Contracts
Nonmonetary notional amount of price risk derivatives, volume | bu		39,995
Economic Hedging [Member] | Future, Maturity Year Two [Member] | Short (Sales) [Member] | Soybean Oil (in pounds) [Member]
Volume of Outstanding Contracts
Nonmonetary notional amount of price risk derivatives, mass | lb		128,760
Economic Hedging [Member] | Future, Maturity Year Three [Member] | Long (Purchases) [Member] | Crude Oil (in thousands of barrels) [Member]
Volume of Outstanding Contracts
Nonmonetary notional amount of price risk derivatives, volume		0
Economic Hedging [Member] | Future, Maturity Year Three [Member] | Long (Purchases) [Member] | Grain (in bushels) [Member]
Volume of Outstanding Contracts
Nonmonetary notional amount of price risk derivatives, volume | bu		10
Economic Hedging [Member] | Future, Maturity Year Three [Member] | Long (Purchases) [Member] | Soybean Oil (in pounds) [Member]
Volume of Outstanding Contracts
Nonmonetary notional amount of price risk derivatives, mass | lb		0
Economic Hedging [Member] | Future, Maturity Year Three [Member] | Short (Sales) [Member] | Crude Oil (in thousands of barrels) [Member]
Volume of Outstanding Contracts
Nonmonetary notional amount of price risk derivatives, volume		0
Economic Hedging [Member] | Future, Maturity Year Three [Member] | Short (Sales) [Member] | Grain (in bushels) [Member]
Volume of Outstanding Contracts
Nonmonetary notional amount of price risk derivatives, volume | bu		75
Economic Hedging [Member] | Future, Maturity Year Three [Member] | Short (Sales) [Member] | Soybean Oil (in pounds) [Member]
Volume of Outstanding Contracts
Nonmonetary notional amount of price risk derivatives, mass | lb		0
Economic Hedging [Member] | Forward Contracts, Maturity Year Two [Member] | Long (Purchases) [Member] | Grain (in bushels) [Member]
Volume of Outstanding Contracts
Nonmonetary notional amount of price risk derivatives, volume | bu		18,336
Economic Hedging [Member] | Forward Contracts, Maturity Year Three [Member] | Long (Purchases) [Member] | Grain (in bushels) [Member]
Volume of Outstanding Contracts
Nonmonetary notional amount of price risk derivatives, volume | bu		65
Trading Derivatives [Member] | Swap, Maturity Year Two [Member] | Long (Purchases) [Member] | Crude Oil (in thousands of barrels) [Member]
Volume of Outstanding Contracts
Nonmonetary notional amount of price risk derivatives, volume		7,739
Trading Derivatives [Member] | Swap, Maturity Year Two [Member] | Short (Sales) [Member] | Crude Oil (in thousands of barrels) [Member]
Volume of Outstanding Contracts
Nonmonetary notional amount of price risk derivatives, volume		7,739
Trading Derivatives [Member] | Swap, Maturity Year Three [Member] | Long (Purchases) [Member] | Crude Oil (in thousands of barrels) [Member]
Volume of Outstanding Contracts
Nonmonetary notional amount of price risk derivatives, volume		0
Trading Derivatives [Member] | Swap, Maturity Year Three [Member] | Short (Sales) [Member] | Crude Oil (in thousands of barrels) [Member]
Volume of Outstanding Contracts
Nonmonetary notional amount of price risk derivatives, volume		0
Trading Derivatives [Member] | Future, Maturity Year Two [Member] | Long (Purchases) [Member] | Crude Oil (in thousands of barrels) [Member]
Volume of Outstanding Contracts
Nonmonetary notional amount of price risk derivatives, volume		38,732
Trading Derivatives [Member] | Future, Maturity Year Two [Member] | Long (Purchases) [Member] | Natural Gas (in millions of btus) [Member]
Volume of Outstanding Contracts
Nonmonetary notional amount of price risk derivatives, millions of Btus | MMBTU		1,400
Trading Derivatives [Member] | Future, Maturity Year Two [Member] | Short (Sales) [Member] | Crude Oil (in thousands of barrels) [Member]
Volume of Outstanding Contracts
Nonmonetary notional amount of price risk derivatives, volume		39,279
Trading Derivatives [Member] | Future, Maturity Year Three [Member] | Long (Purchases) [Member] | Crude Oil (in thousands of barrels) [Member]
Volume of Outstanding Contracts
Nonmonetary notional amount of price risk derivatives, volume		500
Trading Derivatives [Member] | Future, Maturity Year Three [Member] | Long (Purchases) [Member] | Natural Gas (in millions of btus) [Member]
Volume of Outstanding Contracts
Nonmonetary notional amount of price risk derivatives, millions of Btus | MMBTU		0
Trading Derivatives [Member] | Future, Maturity Year Three [Member] | Short (Sales) [Member] | Crude Oil (in thousands of barrels) [Member]
Volume of Outstanding Contracts
Nonmonetary notional amount of price risk derivatives, volume		0
Trading Derivatives [Member] | Options Held, Maturity Year Two [Member] | Long (Purchases) [Member] | Crude Oil (in thousands of barrels) [Member]
Volume of Outstanding Contracts
Nonmonetary notional amount of price risk derivatives, volume		10,800
Trading Derivatives [Member] | Options Held, Maturity Year Two [Member] | Short (Sales) [Member] | Crude Oil (in thousands of barrels) [Member]
Volume of Outstanding Contracts
Nonmonetary notional amount of price risk derivatives, volume		12,400
Trading Derivatives [Member] | Options Held, Maturity Year Three [Member] | Long (Purchases) [Member] | Crude Oil (in thousands of barrels) [Member]
Volume of Outstanding Contracts
Nonmonetary notional amount of price risk derivatives, volume		0
Trading Derivatives [Member] | Options Held, Maturity Year Three [Member] | Short (Sales) [Member] | Crude Oil (in thousands of barrels) [Member]
Volume of Outstanding Contracts
Nonmonetary notional amount of price risk derivatives, volume		0