XML 201 R120.htm IDEA: XBRL DOCUMENT v3.8.0.1
Financial and capital management - Financial instruments measured at amortized cost (Details) - Financial liabilities at amortised cost, category - CAD ($)
$ in Millions
Dec. 31, 2017
Dec. 31, 2016
CRTC tangible benefits obligation    
Disclosure of financial liabilities [line items]    
CARRYING VALUE $ 111 $ 166
FAIR VALUE 110 169
CRTC deferral account obligation    
Disclosure of financial liabilities [line items]    
CARRYING VALUE 124 136
FAIR VALUE 128 145
Debt securities, finance leases and other debt    
Disclosure of financial liabilities [line items]    
CARRYING VALUE 19,321 17,879
FAIR VALUE $ 21,298 $ 20,093