v3.20.1

Fair value of financial instruments - credit valuation (Details) - USD ($) $ in Millions	3 Months Ended		12 Months Ended
	Mar. 31, 2020	Mar. 31, 2019	Dec. 31, 2019
Asset acquisitions
Gain in change in fair value of derivative instruments	$ (5.6)	$ (2.4)
Recurring | Credit valuation adjustments
Asset acquisitions
Net increase in fair value	1.0		$ 1.1
Pre-tax gain in other comprehensive income	0.1		0.1
Gain in change in fair value of derivative instruments	$ 0.9		$ 1.0

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Aggregate net gain (loss) on all derivative instruments recognized in earnings during the period, before tax effects.

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The increase (decrease) during the period in the net carrying value of derivative instruments reported as assets and liabilities that are due to be disposed of within one year (or the normal operating cycle, if longer).

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Amount, before tax and reclassification, of gain (loss) from derivative instrument designated and qualifying cash flow hedge included in assessment of hedge effectiveness.

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