Commitments and Contingencies (Details) € in Millions, $ in Millions						6 Months Ended	9 Months Ended
	Apr. 17, 2020 EUR (€)	Jul. 02, 2019 EUR (€)	Jun. 17, 2019 USD ($)	May 14, 2019 USD ($)	Jul. 14, 2018 USD ($)	Jun. 30, 2016	Sep. 30, 2020 EUR (€) month claim	Dec. 19, 2018 EUR (€)
Tronox Litigation
Loss Contingencies [Line Items]
Gain contingency | $				$ 75
Loss contingency for affirmative defenses and counterclaims | $			$ 400
Neste Engineering Services Arbitration
Loss Contingencies [Line Items]
Loss contingency accrual								€ 14.0
Calais Pipeline Matter
Loss Contingencies [Line Items]
Number of pending claims | claim							2
Tronox Limited
Loss Contingencies [Line Items]
Break fee | $					$ 75
Skangass Oy (Gasum LNG Oy)
Loss Contingencies [Line Items]
Supply agreement original term (years)						10 years
Supply agreement, number of months notice required for termination | month							12
NES | Neste Engineering Services Arbitration
Loss Contingencies [Line Items]
Damages sought		€ 1.6
The Region Hauts-de-France | Calais Pipeline Matter
Loss Contingencies [Line Items]
Damages sought							€ 12.0
Skangass Oy (Gasum LNG Oy) | Gasum Arbitration
Loss Contingencies [Line Items]
Damages sought	€ 27.0