XML 95 R78.htm IDEA: XBRL DOCUMENT v3.8.0.1
Summary of Significant Accounting Policies (Cash, Short-term Investments and Receivables) (Narrative) (Details) - CAD ($)
$ in Millions
12 Months Ended
Dec. 31, 2017
Dec. 31, 2016
Cash and Cash Equivalents [Abstract]    
Short-term Investments $ 222 $ 183
Investment Interest Rate 1.40% 0.60%