RELATED PARTY TRANSACTIONS - Transactions (Details) - Joint ventures - CAD ($) $ in Millions	12 Months Ended
Mar. 31, 2021	Mar. 31, 2020
Disclosure of transactions between related parties [line items]
Revenue	$ 129.2	$ 166.0
Purchases	2.8	2.5
Other income	$ 1.4	$ 1.5

Other income, related party transactions

No definition available.

Name:	cae_Otherincomerelatedpartytransactions
Namespace Prefix:	cae_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

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.

+ References

No definition available.

+ Details

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

- Definition

The amount of goods purchased by the entity in related party transactions. [Refer: Related parties [member]]

+ References

Reference 1: http://www.xbrl.org/2003/role/exampleRef
-Name IAS
-Number 24
-IssueDate 2020-01-01
-Paragraph 21
-Subparagraph a
-URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=24&code=ifrs-tx-2020-en-r&anchor=para_21_a&doctype=Standard
-URIDate 2020-01-01

+ Details

Name:	ifrs-full_PurchasesOfGoodsRelatedPartyTransactions
Namespace Prefix:	ifrs-full_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

The amount of revenue arising from the sale of goods in related party transactions. [Refer: Revenue; Related parties [member]]

+ References

+ Details

Name:	ifrs-full_RevenueFromSaleOfGoodsRelatedPartyTransactions
Namespace Prefix:	ifrs-full_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Details

Name:	ifrs-full_CategoriesOfRelatedPartiesAxis=ifrs-full_JointVenturesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: