Property, Plant, and Equipment - Narrative (Details) $ in Millions	1 Months Ended		3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2021 plant	Sep. 30, 2020 plant	Sep. 30, 2021 USD ($) plant	Sep. 30, 2020 USD ($) plant	Sep. 30, 2021 USD ($)	Sep. 30, 2020 USD ($)	Dec. 31, 2020 plant	Dec. 31, 2019 plant
Ethanol Plants, Jefferson, Wisconsin [Member]
Property, Plant and Equipment (Textual)
Number of ethanol plants with reduced estimated useful life	1
Additional depreciation expense | $			$ 48		$ 48
Number of ethanol plants temporarily idled							1
Number of ethanol plants ceased operations			1
Ethanol Plants, Riga, Michigan [Member]
Property, Plant and Equipment (Textual)
Number of ethanol plants with reduced estimated useful life		1
Additional depreciation expense | $				$ 30		$ 30
Number of ethanol plants temporarily idled								1
Number of ethanol plants ceased operations				1