Contingencies (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2014	Dec. 31, 2018	Oct. 24, 2016
Applicability, Impact and Conclusion of Environmental Loss Contingencies
Environmental contingency accrual	$ 39.3		$ 58.6
Water loss incident | Sinkhole closure remediation plan
Loss Contingencies [Line Items]
Expense related to environmental remediation	80.2
Brazilian subsidiary judicial and administrative proceedings
Loss Contingencies [Line Items]
Estimated loss contingency	90.5
Brazilian subsidiary labor claims
Loss Contingencies [Line Items]
Loss Contingency Accrual	63.2
Brazilian subsidiary Potash Mine occupational hazard
Loss Contingencies [Line Items]
Loss Contingency Accrual	2.7
Brazilian subsidiary mining claims
Loss Contingencies [Line Items]
Loss Contingency Accrual	10.2
Brazilian subsidiary other civil contingent liabilities and other claims
Loss Contingencies [Line Items]
Estimated loss contingency	11.5
Uberaba gypstacks settled litigation
Loss Contingencies [Line Items]
Loss Contingency, Damages Awarded, Value		$ 0.3
Uberaba EHS Class Action pending litigation
Loss Contingencies [Line Items]
Estimated loss contingency	31.8
Tapira Overtime Pay Matter
Loss Contingencies [Line Items]
Loss Contingency Accrual	7.4
Sergipe Overime Pay Matter
Loss Contingencies [Line Items]
Loss Contingency Accrual	4.9
Maximum | Brazilian subsidiary judicial and administrative proceedings
Loss Contingencies [Line Items]
Estimated loss contingency	1,100.0
Maximum | Brazilian Non Income Tax Proceedings
Loss Contingencies [Line Items]
Estimated loss contingency	408.2
Maximum | Brazilian Non Income Tax Proceedings | Indemnification Agreement
Loss Contingencies [Line Items]
Estimated loss contingency	212.0
Maximum | Brazilian Non Income Tax Proceedings | PIS And Cofins cases
Loss Contingencies [Line Items]
Estimated loss contingency	271.0
Maximum | Brazilian subsidiary labor claims
Loss Contingencies [Line Items]
Estimated loss contingency	775.5
Maximum | Brazilian subsidiary environmental claims
Loss Contingencies [Line Items]
Estimated loss contingency	145.9
Loss Contingency Accrual	5.6
Maximum | Brazilian subsidiary mining claims
Loss Contingencies [Line Items]
Estimated loss contingency	16.7
Maximum | Brazilian subsidiary other civil contingent liabilities and other claims
Loss Contingencies [Line Items]
Estimated loss contingency	$ 180.8
Minimum | Water loss incident
Loss Contingencies [Line Items]
Financial assurance to support off-site monitoring and sinkhole remediation costs				$ 40.0