Financial assets and liabilities - Interest rate exposures (Details) - Interest rate risk $ in Millions	Jun. 30, 2018 CAD ($)
Disclosure of detailed information about hedging instruments [line items]
Percentage of possible change in risk variable	1.00%
Reasonably possible change in risk variable impact on net earnings	$ 31

Line items represent concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes of the table.

No definition available.

Name:	ifrs-full_DisclosureOfDetailedInformationAboutHedgingInstrumentsLineItems
Namespace Prefix:	ifrs-full_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration