advance billings and customer deposits (Details) - CAD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018
advance billings and customer deposits
Advance billings	$ 522	$ 538
Deferred customer activation and connection fees	9	10
Customer deposits	14	13
Contract liabilities	545	561
Other	130	95
Total	$ 675	$ 656

The amount of current contract liabilities. [Refer: Contract liabilities]

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name IFRS
-Number 15
-IssueDate 2019-01-01
-Paragraph 105
-URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=15&code=ifrs-tx-2019-en-r&anchor=para_105&doctype=Standard
-URIDate 2019-03-27

+ Details

Name:	ifrs-full_CurrentContractLiabilities
Namespace Prefix:	ifrs-full_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

The amount of deposit liabilities from customers held by the entity.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Name IAS
-Number 1
-IssueDate 2019-01-01
-Paragraph 55
-URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=1&code=ifrs-tx-2019-en-r&anchor=para_55&doctype=Standard
-URIDate 2019-03-27

+ Details

Name:	ifrs-full_DepositsFromCustomers
Namespace Prefix:	ifrs-full_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

The amount of current liabilities that the entity does not separately disclose in the same statement or note. [Refer: Current liabilities]

+ References

+ Details

Name:	ifrs-full_OtherCurrentLiabilities
Namespace Prefix:	ifrs-full_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Represents the amount of liability representing advance billings for income that is received but not yet earned.

+ References

No definition available.

+ Details

Name:	tu_AdvanceBilling
Namespace Prefix:	tu_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

The amount of advance billings, deferred customer activation and connection fees, customer deposits, and regulatory deferral accounts.

+ References

No definition available.

+ Details

Name:	tu_AdvanceBillingsAndCustomerDeposits
Namespace Prefix:	tu_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

n/a

+ References

No definition available.

+ Details

Name:	tu_AdvanceBillingsAndCustomerDepositsAbstract
Namespace Prefix:	tu_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Represents the deferred customer activation and connection fees component of advance billings and customer deposits recognized in current liabilities.

+ References

No definition available.

+ Details

Name:	tu_DeferredCustomerActivationAndConnectionFeesCurrentLiabilities
Namespace Prefix:	tu_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant