XML 192 R164.htm IDEA: XBRL DOCUMENT v3.20.4
Common Shares - The effects of the Corporation's purchase and cancellation of the common shares (Details)
$ / shares in Units, $ in Millions
 12 Months Ended
Dec. 31, 2020
CAD ($)
$ / shares
shares
Dec. 31, 2019
CAD ($)
$ / shares
shares
Dec. 31, 2018
CAD ($)
$ / shares
shares
Disclosure of classes of share capital [line items]      
Deficit $ (1,826) $ (1,455)  
Number of shares issued and fully paid that were not cancelled due to timing differences between the transaction date and settlement date | shares 456,200 189,900  
NCIB Program      
Disclosure of classes of share capital [line items]      
Number of shares issued and fully paid | shares 7,352,600 7,716,300 3,264,500
Par value per share | $ / shares $ 8.33 $ 8.80 $ 7.02
Issued capital $ 61 $ 68 $ 23
Weighted average share price 79 83  
Deficit $ 18 $ 15  
Par value per share | $ / shares $ 8.33 $ 8.80 $ 7.02
Common shares      
Disclosure of classes of share capital [line items]      
Issued capital $ 2,896 $ 2,978 $ 3,059