Commitments and Contingencies (Litigation and Environmental Narrative) (Details) R$ in Millions	1 Months Ended	12 Months Ended
	Sep. 30, 2010 BRL (R$)	Sep. 30, 2020 USD ($)	Sep. 30, 2020 BRL (R$) site	Sep. 30, 2020 USD ($) site	Sep. 30, 2019 USD ($)
Alleged Anticompete Litigation
Loss Contingencies [Line Items]
Civil fines imposed	R$ 179.2	$ 32,000,000
Provision for litigation		$ 0
Maximum of loss contingency range subject to interest			R$ 179.2	$ 32,000,000
Environmental
Loss Contingencies [Line Items]
Approximate number of sites on which settlement has not been reached | site			31	31
Accrual for environmental loss contingencies				$ 84,700,000	$ 68,900,000
Accrual for environmental loss contingencies, maximum payout period		30 years
Environmental | Minimum
Loss Contingencies [Line Items]
Estimate of possible exposure from environment loss contingencies				84,000,000
Environmental | Maximum
Loss Contingencies [Line Items]
Estimate of possible exposure from environment loss contingencies				$ 98,000,000