Foreign exchange variations, net (Details) - BRL (R$) R$ in Thousands	12 Months Ended
Dec. 31, 2025	Dec. 31, 2024	Dec. 31, 2023
IfrsStatementLineItems [Line Items]
Income	R$ 207,264	R$ 305,190	R$ 194,035
Expenses	(270,928)	(233,827)	(201,092)
Foreign exchange variations	(63,664)	71,363	(7,057)
Loans And Financing [Member]
IfrsStatementLineItems [Line Items]
Income	10,820		125,981
Expenses	(7,262)	(57,124)	(10,698)
Suppliers [Member]
IfrsStatementLineItems [Line Items]
Income	107,602	21,370	33,680
Expenses	(73,615)	(85,447)	(19,336)
Swap contract [member]
IfrsStatementLineItems [Line Items]
Income	7,276	106,453	10,698
Expenses	(10,819)	(49,310)	(125,981)
Accounts Receivables [Member]
IfrsStatementLineItems [Line Items]
Income	55,330	135,389	23,676
Expenses	(118,107)	(36,081)	(45,077)
Financial Assets [Member]
IfrsStatementLineItems [Line Items]
Income	26,236	41,978
Expenses	R$ (61,125)	R$ (5,865)

The amount of exchange differences recognised in profit or loss that arise from foreign currency transactions, excluding those arising on financial instruments measured at fair value through profit or loss in accordance with IFRS 9. [Refer: At fair value [member]; Classes of financial instruments [domain]]

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name IAS
-Number 21
-IssueDate 2024-01-01
-Paragraph 52
-Subparagraph a
-URI https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=21&code=ifrs-tx-2024-en-r&anchor=para_52_a&doctype=Standard
-URIDate 2024-03-27

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Name IAS
-Number 1
-IssueDate 2024-01-01
-Paragraph 35
-URI https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=1&code=ifrs-tx-2024-en-r&anchor=para_35&doctype=Standard
-URIDate 2024-03-27

+ Details

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

- Definition

The net gain arising from exchange differences recognised in profit or loss, excluding those arising on financial instruments measured at fair value through profit or loss in accordance with IFRS 9. [Refer: Foreign exchange gain (loss)]

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Name IAS
-Number 21
-IssueDate 2024-01-01
-Paragraph 52
-Subparagraph a
-URI https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=21&code=ifrs-tx-2024-en-r&anchor=para_52_a&doctype=Standard
-URIDate 2024-03-27

Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef
-Name IAS
-Number 1
-IssueDate 2024-01-01
-Paragraph 35
-URI https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=1&code=ifrs-tx-2024-en-r&anchor=para_35&doctype=Standard
-URIDate 2024-03-27

+ Details

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

- Definition

The net loss arising from exchange differences recognised in profit or loss, excluding those arising on financial instruments measured at fair value through profit or loss in accordance with IFRS 9. [Refer: Foreign exchange gain (loss)]

+ References

+ Details

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

- References

No definition available.

+ Details

Name:	timb_IfrsStatementLineItems
Namespace Prefix:	timb_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Details

Name:	ifrs-full_ClassesOfFinancialInstrumentsAxis=timb_LoansAndFinancingMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	ifrs-full_ClassesOfFinancialInstrumentsAxis=timb_SuppliersMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	ifrs-full_ClassesOfFinancialInstrumentsAxis=ifrs-full_SwapContractMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	ifrs-full_ClassesOfFinancialInstrumentsAxis=timb_AccountsReceivablesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	ifrs-full_ClassesOfFinancialInstrumentsAxis=timb_FinancialAssetsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: