revenue from contracts with customers - Accounts receivable (Details) - CAD ($) $ in Millions	Jun. 30, 2020	Dec. 31, 2019
revenue from contracts with customers
Customer accounts receivable	$ 1,719	$ 1,570
Accrued receivables - customer	220	180
Allowance for doubtful accounts	(94)	(46)
Total	1,845	1,704
Accrued receivables - other	159	258
Accounts receivable - current	$ 2,004	$ 1,962

The amount of current accrued income. [Refer: Accrued income]

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Name IAS
-Number 1
-IssueDate 2019-01-01
-Paragraph 112
-Subparagraph c
-URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=1&code=ifrs-tx-2019-en-r&anchor=para_112_c&doctype=Standard
-URIDate 2019-03-27

+ Details

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

- Definition

The amount of current receivables from contracts with customers. [Refer: Receivables from contracts with customers]

+ References

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

- Definition

The amount of current other receivables. [Refer: Other receivables]

+ References

Reference 1: http://www.xbrl.org/2003/role/exampleRef
-Name IAS
-Number 1
-IssueDate 2019-01-01
-Paragraph 78
-Subparagraph b
-URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=1&code=ifrs-tx-2019-en-r&anchor=para_78_b&doctype=Standard
-URIDate 2019-03-27

+ Details

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

- Definition

The amount of current trade receivables and current other receivables. [Refer: Current trade receivables; Other current receivables]

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name IAS
-Number 1
-IssueDate 2019-01-01
-Paragraph 54
-Subparagraph h
-URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=1&code=ifrs-tx-2019-en-r&anchor=para_54_h&doctype=Standard
-URIDate 2019-03-27

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Name IAS
-Number 1
-IssueDate 2019-01-01
-Paragraph 78
-Subparagraph b
-URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=1&code=ifrs-tx-2019-en-r&anchor=para_78_b&doctype=Standard
-URIDate 2019-03-27

+ Details

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

- References

No definition available.

+ Details

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

- Definition

The amount due from contracts with customers for goods or services that have been delivered or sold in the normal course of business, reduced to their estimated net realizable fair value by an allowance established by the entity of the amount it deems uncertain of collection.

+ References

No definition available.

+ Details

Name:	tu_CurrentReceivablesFromContractsWithCustomersNet
Namespace Prefix:	tu_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

For an unclassified balance sheet, a valuation allowance for receivables due a company that are expected to be uncollectible.

+ References

No definition available.

+ Details

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