Income taxes (Tables)

6 Months Ended

Jun. 30, 2018

Income taxes

Schedule of components of income tax benefit

	Three Months Ended June 30,				Six Months Ended June 30,
	2018		2017		2018		2017
Current income tax expense	$	1.1	$	1.4	$	2.2	$	2.3
Deferred income tax (benefit) expense		(0.2)		(23.7)		2.0		(24.9)
Total income tax expense (benefit), net	$	0.9	$	(22.3)	$	4.2	$	(22.6)