Income Taxes - Provision for (Recovery of) Income Taxes (Details) - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2018	Dec. 31, 2017
Current income tax
Current year expense	$ 144.1	$ 200.6
Adjustments to prior years’ income taxes	5.1	(22.6)
Current income tax	149.2	178.0
Deferred income tax
Origination and reversal of temporary differences	(108.1)	(22.5)
Adjustments to prior years' deferred income taxes	(1.6)	24.3
Change in tax rate related to U.S. tax reform	0.0	222.4
Other	4.7	6.1
Deferred income tax	(105.0)	230.3
Provision for income taxes	$ 44.2	$ 408.3

Deferred Tax Expense (Income) And Adjustments For Deferred Tax Of Prior Periods

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Deferred Tax Expense (Income) And Adjustments For Deferred Tax Of Prior Periods [Abstract]

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No definition available.

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Adjustments of tax expense (income) recognised in the period for current tax of prior periods.

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Adjustments of tax expense (income) recognised in the period for the deferred tax of prior periods.

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The amount of income taxes payable (recoverable) in respect of the taxable profit (tax loss) for a period.

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The amount of current tax expense (income) and adjustments for the current tax of prior periods. [Refer: Current tax expense (income); Adjustments for current tax of prior periods]

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The amount of deferred tax expense or income relating to the creation or reversal of temporary differences. [Refer: Temporary differences [member]; Deferred tax expense (income)]

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The amount of deferred tax expense or income relating to tax rate changes or the imposition of new taxes. [Refer: Deferred tax expense (income)]

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The aggregate amount included in the determination of profit (loss) for the period in respect of current tax and deferred tax. [Refer: Current tax expense (income); Deferred tax expense (income)]

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The amount of components of deferred tax expense or income that the entity does not separately disclose in the same statement or note. [Refer: Deferred tax expense (income)]

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