FINANCIAL INSTRUMENTS - Counterparty credit risk management (Details) - CAD ($) $ in Millions	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Disclosure of detailed information about financial instruments [line items]
Expected credit loss rate	1.00%
Derivative financial asset (liability), net	$ 356	$ 101	$ 489
Credit risk
Disclosure of detailed information about financial instruments [line items]
Derivative financial asset (liability), net	$ 361	$ 187

The rate of expected credit losses, calculated as percentage of the gross carrying amount. Expected credit losses are the weighted average of credit losses with the respective risks of a default occurring as the weights.

Reference 1: http://www.xbrl.org/2003/role/exampleRef
-Name IFRS
-Number 7
-IssueDate 2018-01-01
-Paragraph IG20D
-URI http://eifrs.ifrs.org/eifrs/XBRL?type=IFRS&num=7&date=2018-03-01&anchor=para_IG20D&doctype=Implementation%20Guidance
-URIDate 2018-03-16

Reference 2: http://www.xbrl.org/2003/role/exampleRef
-Name IFRS
-Number 7
-IssueDate 2018-01-01
-Paragraph 35N
-URI http://eifrs.ifrs.org/eifrs/XBRL?type=IFRS&num=7&date=2018-03-01&anchor=para_35N&doctype=Standard
-URIDate 2018-03-16

Name:	ifrs-full_ExpectedCreditLossRate
Namespace Prefix:	ifrs-full_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant