Commitments and Contingencies (Litigation and Environmental - Narrative) (Details) R$ in Millions	1 Months Ended	6 Months Ended
	Sep. 30, 2010 BRL (R$)	Mar. 31, 2020 USD ($) site	Mar. 31, 2020 BRL (R$) site	Sep. 30, 2019 USD ($)
Alleged Anticompete Litigation
Loss Contingencies [Line Items]
Civil fines imposed	R$ 179.2	$ 34,000,000
Provision for litigation		0
Maximum of loss contingency range subject to interest		$ 34,000,000	R$ 179.2
Environmental
Loss Contingencies [Line Items]
Approximate number of sites on which settlement has not been reached | site		31	31
Accrual for environmental loss contingencies		$ 87,200,000		$ 68,900,000
Accrual for environmental loss contingencies, maximum payout period		30 years
Environmental | Minimum
Loss Contingencies [Line Items]
Estimate of possible exposure from environmental loss contingencies		$ 87,000,000
Environmental | Maximum
Loss Contingencies [Line Items]
Estimate of possible exposure from environmental loss contingencies		$ 100,000,000