Commitments - Additional Information (Detail) - CAD ($) $ in Millions	12 Months Ended
Dec. 31, 2018	Dec. 31, 2017
Commitments [abstract]
Premises rental expense	$ 181.7	$ 178.1
Sublease rental income	7.2	7.4
Future minimum sublease payments expected to be received under noncancellable sublease agreements	$ 19.2	$ 16.8

The amount of future minimum sublease payments expected to be received under non-cancellable subleases for operating leases. Minimum lease payments are payments over the lease term that the lessee is, or can be, required to make, excluding contingent rent, costs for services and taxes to be paid by, and reimbursed to, the lessor, together with: (a) for a lessee, any amounts guaranteed by the lessee or by a party related to the lessee; or (b) for a lessor, any residual value guaranteed to the lessor by: (i) the lessee; (ii) a party related to the lessee; or (iii) a third party unrelated to the lessor that is financially capable of discharging the obligations under the guarantee.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Note Expiry date 2019-01-01
-Name IAS
-Number 17
-IssueDate 2018-01-01
-Paragraph 35
-Subparagraph b
-URI http://eifrs.ifrs.org/eifrs/XBRL?type=IAS&num=17&date=2018-03-02&anchor=para_35_b&doctype=Standard&book=b
-URIDate 2018-03-16

Name:	ifrs-full_ExpectedFutureMinimumSubleasePaymentsReceivableUnderNoncancellableSubleasesClassifiedAsOperatingLease
Namespace Prefix:	ifrs-full_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant