Derivative Financial Instruments - Summary of Financial Derivatives at Fair Value (Parenthetical) (Detail) $ in Millions	Oct. 31, 2020 CAD ($)
Disclosure of financial assets [abstract]
Average fair value of trading derivatives, Favourable	$ 44,942
Average fair value of trading derivatives, Unfavourable	$ 44,332

Average fair value of trading derivative liabilities.

No definition available.

Name:	bns_AverageFairValueOfTradingDerivativeLiabilities
Namespace Prefix:	bns_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant