v2.4.0.6
Guarantees and condensed consolidating financial information (Details 4) (USD $)
In Millions, unless otherwise specified
 3 Months Ended
Mar. 31, 2013
Mar. 31, 2012
Condensed consolidating statement of operations and comprehensive income    
Net income (loss) $ 7.8 $ (39.2)
Other comprehensive income (loss):    
Net amount reclassified to earnings 0.3 0.3
Net unrealized losses on derivatives 0.3 0.3
Foreign currency translation adjustments (12.1) 17.2
Other comprehensive loss, net of tax (11.8) 17.5
Comprehensive income loss (4.0) (21.7)
Less: Comprehensive income attributable to noncontrolling interests 1.3 3.1
Comprehensive income loss attributable to Atlantic Power Corporation (5.3) (24.8)
Guarantor Subsidiaries
    
Condensed consolidating statement of operations and comprehensive income    
Net income (loss) 12.9  
Other comprehensive income (loss):    
Net amount reclassified to earnings 0.3  
Net unrealized losses on derivatives 0.3  
Foreign currency translation adjustments (12.1)  
Other comprehensive loss, net of tax (11.8)  
Comprehensive income loss 1.1  
Less: Comprehensive income attributable to noncontrolling interests 1.3  
Comprehensive income loss attributable to Atlantic Power Corporation (0.2)  
Curtis Palmer
    
Condensed consolidating statement of operations and comprehensive income    
Net income (loss) 0.6  
Other comprehensive income (loss):    
Comprehensive income loss 0.6  
Comprehensive income loss attributable to Atlantic Power Corporation 0.6  
Atlantic Power
    
Condensed consolidating statement of operations and comprehensive income    
Net income (loss) (5.6)  
Other comprehensive income (loss):    
Comprehensive income loss (5.6)  
Comprehensive income loss attributable to Atlantic Power Corporation (5.6)  
Eliminations
    
Condensed consolidating statement of operations and comprehensive income    
Net income (loss) (0.1)  
Other comprehensive income (loss):    
Comprehensive income loss (0.1)  
Comprehensive income loss attributable to Atlantic Power Corporation $ (0.1)