Finance Costs, Net - Components of Net Interest Expense (Detail) - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2025	Dec. 31, 2024
Interest expense:
Debt	$ 113	$ 140
Other, net	30	23
Fair value (gains) losses on financial instruments (see note 20)
Debt	(14)	0
Fair value hedges	14	0
Cash flow hedges, transfer from equity	(27)	88
Net foreign exchange losses (gains) on debt	27	(88)
Net interest expense - debt and other	143	163
Net interest expense - leases	14	14
Net interest expense - pension and other post-employment benefit plans	26	24
Interest income	(40)	(76)
Net interest expense	$ 143	$ 125

No definition available.

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

- References

No definition available.

+ Details

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

- References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Name IAS
-Number 19
-IssueDate 2025-01-01
-Paragraph 135
-Subparagraph b
-URI https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=19&code=ifrs-tx-2025-en-r&anchor=para_135_b&doctype=Standard
-URIDate 2025-03-27

+ Details

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

- References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Note Expiry date 2027-01-01
-Name IAS
-Number 1
-IssueDate 2025-01-01
-Paragraph 112
-Subparagraph c
-URI https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=1&code=ifrs-tx-2025-en-b&anchor=para_112_c&doctype=Standard
-URIDate 2025-03-27

+ Details

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

- References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name IFRS
-Number 16
-IssueDate 2025-01-01
-Paragraph 53
-Subparagraph b
-URI https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=16&code=ifrs-tx-2025-en-r&anchor=para_53_b&doctype=Standard
-URIDate 2025-03-27

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Note Effective 2027-01-01
-Name IFRS
-Number 19
-IssueDate 2025-01-01
-Paragraph 115
-Subparagraph b
-URI https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=19&code=ifrs-tx-2025-en-r&anchor=para_115_b&doctype=Standard
-URIDate 2025-03-27

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Note Effective 2027-01-01
-Name IFRS
-Number 19
-IssueDate 2025-01-01
-Paragraph 115
-Subparagraph b
-URI https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=19&code=ifrs-tx-2025-en-r&anchor=para_115_b&doctype=Standard
-URIDate 2025-03-27

+ Details

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

- References

+ Details

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

- References

+ Details

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

- References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name IFRS
-Number 8
-IssueDate 2025-01-01
-Paragraph 28
-Subparagraph e
-URI https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=8&code=ifrs-tx-2025-en-r&anchor=para_28_e&doctype=Standard
-URIDate 2025-03-27

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Name IFRS
-Number 8
-IssueDate 2025-01-01
-Paragraph 23
-URI https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=8&code=ifrs-tx-2025-en-r&anchor=para_23&doctype=Standard
-URIDate 2025-03-27

Reference 3: http://www.xbrl.org/2009/role/commonPracticeRef
-Note Expiry date 2027-01-01
-Name IAS
-Number 1
-IssueDate 2025-01-01
-Paragraph 85
-URI https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=1&code=ifrs-tx-2025-en-b&anchor=para_85&doctype=Standard
-URIDate 2025-03-27

+ Details

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

- Definition

Fair Value (Gains) Losses On Financial Instruments On Debt

+ References

No definition available.

+ Details

Name:	tri_FairValueGainsLossesOnFinancialInstrumentsOnDebt
Namespace Prefix:	tri_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Fair Value (Gains) Losses On Financial Instruments On Fair value hedges.

+ References

No definition available.

+ Details

Name:	tri_FairValueGainsLossesOnFinancialInstrumentsOnFairValueHedges
Namespace Prefix:	tri_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

The amount of exchange differences recognised in profit or loss that arise from foreign currency transactions related to with debt instruments.

+ References

No definition available.

+ Details

Name:	tri_GainsLossesRecognizedInProfitLossAriseFromForeignCurrencyTranslationRelatedToDebt
Namespace Prefix:	tri_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Net interest expense from debt and other.

+ References

No definition available.

+ Details

Name:	tri_NetInterestExpenseFromDebtAndOther
Namespace Prefix:	tri_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Reclassification adjustments on cash flow hedges, net of tax foreign exchange

+ References

No definition available.

+ Details

Name:	tri_ReclassificationAdjustmentsOnCashFlowHedgesNetOfTaxForeignExchange
Namespace Prefix:	tri_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration