Financial Instruments, Derivatives and Hedging Activities - Commodity price hedging (Details) bu in Millions, MMBTU in Millions	6 Months Ended
	Jun. 30, 2021 MMBTU bu
Commodity Contracts | Minimum
Financial instruments, derivatives and hedging activities
Maturity period of price risk derivative	12 months
Commodity Contracts | Maximum
Financial instruments, derivatives and hedging activities
Maturity period of price risk derivative	24 months
Corn Commodity
Financial instruments, derivatives and hedging activities
Futures contract (in bushels for corn and gallons for ethanol) | bu	71
Natural Gas Commodity
Financial instruments, derivatives and hedging activities
Natural gas futures contract (in mmbtu) | MMBTU	35