CONSOLIDATED STATEMENTS OF COMPREHENSIVE LOSS - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
CONSOLIDATED STATEMENTS OF COMPREHENSIVE (LOSS) INCOME
Net loss	$ (19.8)	$ (16.3)	$ (20.3)	$ (29.3)
Other comprehensive loss, net of tax:
Unrealized loss on hedging activities	(0.1)	(0.2)	(0.3)	(0.7)
Net amount reclassified to earnings	0.1	0.2	0.4	0.4
Net unrealized gain (loss) on derivatives			0.1	(0.3)
Defined benefit plan, net of tax			0.1
Foreign currency translation adjustments	4.7	1.0	6.7	19.4
Other comprehensive income, net of tax	4.7	1.0	6.9	19.1
Comprehensive loss	(15.1)	(15.3)	(13.4)	(10.2)
Less: Comprehensive income attributable to preferred share dividends of a subsidiary company	2.1	2.2	4.3	4.2
Comprehensive loss attributable to Atlantic Power Corporation	$ (17.2)	$ (17.5)	$ (17.7)	$ (14.4)