XML 151 R95.htm IDEA: XBRL DOCUMENT v3.8.0.1
Pension and Non-pension Post-employment Benefit Plans - Actuarial Gains and Losses, Net of Tax, Recognized in OCI (Details) - USD ($)
 1 Months Ended 12 Months Ended
Mar. 31, 2017
Dec. 31, 2017
Dec. 31, 2016
Dec. 31, 2015
Disclosure of analysis of other comprehensive income by item [line items]        
Loss on pension annuity purchase (see note 16(c))   $ 17,000,000 $ 0 $ 0
Actuarial losses recognized during the year   1,200,000 (17,100,000) 7,000,000
Income tax (recovery) expense   0 1,400,000 0
Income tax (recovery) expense   (700,000) (700,000) (2,100,000)
Pension and non-pension post-employment benefit plans        
Disclosure of analysis of other comprehensive income by item [line items]        
Cumulative losses, beginning of year   (4,100,000) 13,000,000 6,000,000
Actuarial losses recognized during the year $ 17,000,000      
Cumulative losses (gains), end of year   $ 14,100,000 $ (4,100,000) $ 13,000,000