Income Taxes Incomes Taxes (Details) $ in Millions, $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2020 USD ($)	Sep. 30, 2019 USD ($)	Sep. 30, 2020 USD ($)	Sep. 30, 2020 CAD ($)	Sep. 30, 2019 USD ($)	Jul. 31, 2020 USD ($)	Oct. 31, 2016 USD ($)	Oct. 31, 2016 CAD ($)
Operating Loss Carryforwards [Line Items]
Effective Income Tax Rate Reconciliation, Percent	155.00%	14.60%	9.40%	9.40%	17.10%
Effective Income Tax Rate Reconciliation, Tax Settlement, Amount			$ 25.0
Income tax provision (benefit)	$ 13.0	$ (19.0)	(33.0)		$ (113.0)
Income (Loss) from Continuing Operations before Equity Method Investments, Income Taxes, Noncontrolling Interest	(9.0)	133.0	346.0		665.0
Less: Net earnings attributable to noncontrolling interest	32.0	$ 49.0	83.0		$ 114.0
Income Tax Examination, Liability (Refund) Adjustment from Settlement with Taxing Authority	108.0		108.0
Unrecognized Tax Benefits, Decrease Resulting from Settlements with Taxing Authorities	12.0		19.0
Unrecognized Tax Benefits, Decrease Resulting from Prior Period Tax Positions	7.0
Income Tax Examination, Liability (Refund) Adjustment from Settlement with Taxing Authority, Withholding Tax Matter	40.0		40.0			$ 2.0
Income Tax Examination, Liability (Refund) Adjustment from Settlement with Taxing Authority, Income Tax Matter	(68.0)		$ (68.0)
Income Tax Examination, Interest Income, Net of Tax	$ 13.0
Effective Income Tax Rate Reconciliation, period increase/(decrease) due to noncontrolling interest	121.60%	8.50%	3.00%	3.00%	3.50%
Line of Credit Facility, Fair Value of Amount Outstanding	$ 500.0		$ 500.0
Deferred Tax Assets, Capital Loss Carryforwards	90.0		90.0
Deferred Tax Assets, Valuation Allowance	90.0		90.0
Canada Revenue Agency [Member]
Operating Loss Carryforwards [Line Items]
Income Tax Examination, Estimate of Possible Loss			131.0	$ 174
Line of Credit Facility, Fair Value of Amount Outstanding							$ 74.0	$ 98
Foreign Currency Translation Adjustment
Operating Loss Carryforwards [Line Items]
Other Comprehensive Income Pension and Other Postretirement Benefit Plans Arising During Period Before Tax			$ 0.0		$ 0.0
Domestic Tax Authority [Member]
Operating Loss Carryforwards [Line Items]
Income tax provision (benefit)	16.0
Income Tax Examination, Interest Income	$ 16.0
LOUISIANA | State and Local Jurisdiction
Operating Loss Carryforwards [Line Items]
Effective Income Tax Rate Reconciliation, Tax Credit, Investment, Amount					$ (30.0)