XML 57 R43.htm IDEA: XBRL DOCUMENT v3.10.0.1
Components of accumulated other comprehensive loss (Details) - USD ($)
$ in Millions
 3 Months Ended 9 Months Ended
Sep. 30, 2018
Sep. 30, 2017
Sep. 30, 2018
Sep. 30, 2017
Dec. 31, 2017
Accumulated Other Comprehensive Income (Loss) [Line Items]          
Other comprehensive loss before income tax effect $ (95.2)   $ (95.2)   $ (99.4)
Income tax effect 6.5   6.5   7.7
Accumulated other comprehensive loss (88.7)   (88.7)   (91.7)
AOCI Attributable to Parent, Net of Tax [Roll Forward]          
Equity, beginning balance     829.6    
Equity, ending balance 833.5   833.5    
Defined benefit plan and other postretirement liabilities [Member]          
Accumulated Other Comprehensive Income (Loss) [Line Items]          
Other comprehensive loss before income tax effect (97.7)   (97.7)   (102.1)
Income tax effect 7.0   7.0   8.2
AOCI Attributable to Parent, Net of Tax [Roll Forward]          
Equity, beginning balance (90.8) $ (115.2) (93.8) $ (116.2)  
Net amount reclassified to net income (loss) 0.1 1.0 3.2 2.0  
Equity, ending balance (90.7) (114.2) (90.7) (114.2)  
Unrealized gain (loss) on financial instruments [Member]          
Accumulated Other Comprehensive Income (Loss) [Line Items]          
Other comprehensive loss before income tax effect 2.5   2.5   2.7
Income tax effect (0.5)   (0.5)   $ (0.5)
AOCI Attributable to Parent, Net of Tax [Roll Forward]          
Equity, beginning balance 2.1 2.2 2.1 2.3  
Net amount reclassified to net income (loss) 0.0 0.0 (0.1) (0.1)  
Equity, ending balance 2.1 2.2 2.1 2.2  
AOCI Attributable to Parent [Member]          
AOCI Attributable to Parent, Net of Tax [Roll Forward]          
Equity, beginning balance (88.7) (113.0) (91.7) (113.9)  
Net amount reclassified to net income (loss) 0.1 1.0 3.1 1.9  
Equity, ending balance $ (88.7) $ (112.0) $ (88.7) $ (112.0)