Sensitivity analysis (Details 1) - BRL (R$) R$ in Thousands	Dec. 31, 2025	Dec. 31, 2024
IfrsStatementLineItems [Line Items]
Financial assets measured at amortized cost	R$ 42,521,279	R$ 27,583,439
Financial assets measured at amortized cost - 10%	(352,850)	(270,796)
Financial assets measured at amortized cost - (10%)	352,850	270,796
Financial assets measured at fair value through profit or loss	3,102,639	1,105,089
Financial assets measured at fair value through profit or loss - 10%	39,717	46,349
Financial assets measured at fair value through profit or loss - (10%)	(39,717)	(46,349)
Other liabilities	(10,397,287)
Other Liabilities - 10%	161,526
Other Liabilities - (10%)	(161,526)
Financial liabilities measured at amortized cost	(31,699,084)	(20,841,533)
Financial liabilities measured at amortized cost - 10%	(174,536)	(59,460)
Financial liabilities measured at amortized cost - (10%)	174,536	59,460
Financial assets measured at fair value through other comprehensive income		14,394
Financial assets measured at fair value through other comprehensive income - 10%		156
Financial assets measured at fair value through other comprehensive income - (10%)		(156)
Obligations related to credit assignments		(4,459,629)
Obligations related to credit assignments - 10%		79,518
Obligations related to credit assignments - (10%)		(79,518)
Debentures [Member]
IfrsStatementLineItems [Line Items]
Financial assets measured at amortized cost	1,739,683	1,392,720
Financial assets measured at amortized cost - 10%	(10,745)	10,030
Financial assets measured at amortized cost - (10%)	10,745	(10,030)
Debentures 1 [Member]
IfrsStatementLineItems [Line Items]
Financial assets measured at amortized cost	3,941,507
Financial assets measured at amortized cost - 10%	51,111
Financial assets measured at amortized cost - (10%)	(51,111)
Gross Credit Potfolio [Member]
IfrsStatementLineItems [Line Items]
Financial assets measured at amortized cost	34,365,118	24,286,705
Financial assets measured at amortized cost - 10%	(378,095)	(265,398)
Financial assets measured at amortized cost - (10%)	378,095	265,398
Government Securities Other Countries I C O [Member]
IfrsStatementLineItems [Line Items]
Financial assets measured at amortized cost	1,511,277
Financial assets measured at amortized cost - 10%	(14,989)
Financial assets measured at amortized cost - (10%)	14,989
Government Securities Other Countries K D B [Member]
IfrsStatementLineItems [Line Items]
Financial assets measured at amortized cost	289,509	533,966
Financial assets measured at amortized cost - 10%	(2,103)	(4,247)
Financial assets measured at amortized cost - (10%)	2,103	4,247
National Treasury Notes [Member]
IfrsStatementLineItems [Line Items]
Financial assets measured at amortized cost	94,070	90,866
Financial assets measured at amortized cost - 10%	384	419
Financial assets measured at amortized cost - (10%)	(384)	(419)
Investment Securities National Treasury Bills [Member]
IfrsStatementLineItems [Line Items]
Financial assets measured at amortized cost	256,000	1,174,990
Financial assets measured at amortized cost - 10%	(2,616)	(12,729)
Financial assets measured at amortized cost - (10%)	2,616	12,729
Financial assets measured at fair value through profit or loss	646,754
Financial assets measured at fair value through profit or loss - 10%	(6,596)
Financial assets measured at fair value through profit or loss - (10%)	6,596
Financial Treasury Bills [Member]
IfrsStatementLineItems [Line Items]
Financial assets measured at amortized cost	324,115	104,192
Financial assets measured at amortized cost - 10%	4,203	1,129
Financial assets measured at amortized cost - (10%)	(4,203)	(1,129)
Financial Instruments Derivatives [Member]
IfrsStatementLineItems [Line Items]
Financial assets measured at fair value through profit or loss	250,582	407,994
Financial assets measured at fair value through profit or loss - 10%	23,175	39,330
Financial assets measured at fair value through profit or loss - (10%)	(23,175)	(39,330)
Investment Securities Financial Treasury Bills [Member]
IfrsStatementLineItems [Line Items]
Financial assets measured at fair value through profit or loss	1,722,314	555,577
Financial assets measured at fair value through profit or loss - 10%	22,335	5,991
Financial assets measured at fair value through profit or loss - (10%)	(22,335)	(5,991)
Investment Securities Financial Bills [Member]
IfrsStatementLineItems [Line Items]
Financial assets measured at fair value through profit or loss	210,891	1,073
Financial assets measured at fair value through profit or loss - 10%	2,735	12
Financial assets measured at fair value through profit or loss - (10%)	(2,735)	(12)
Investment Securities National Treasury Notes [Member]
IfrsStatementLineItems [Line Items]
Financial assets measured at fair value through profit or loss	139,335
Financial assets measured at fair value through profit or loss - 10%	(1,141)
Financial assets measured at fair value through profit or loss - (10%)	1,141
Investments Fund Quotas [Member]
IfrsStatementLineItems [Line Items]
Financial assets measured at fair value through profit or loss	132,763	140,445
Financial assets measured at fair value through profit or loss - 10%	(791)	1,016
Financial assets measured at fair value through profit or loss - (10%)	791	(1,016)
Obligations Related To Credit Assignments [Member]
IfrsStatementLineItems [Line Items]
Other liabilities	(10,397,287)
Other Liabilities - 10%	161,526
Other Liabilities - (10%)	(161,526)
Obligations related to credit assignments		(4,459,629)
Obligations related to credit assignments - 10%		79,518
Obligations related to credit assignments - (10%)		(79,518)
Demand Customer Deposits [Member]
IfrsStatementLineItems [Line Items]
Financial liabilities measured at amortized cost	(345,801)	(320,208)
Financial liabilities measured at amortized cost - 10%
Financial liabilities measured at amortized cost - (10%)
Funds From Acceptances And Issuance Of Securities [Member]
IfrsStatementLineItems [Line Items]
Financial liabilities measured at amortized cost	(6,152,941)
Financial liabilities measured at amortized cost - 10%	(79,891)
Financial liabilities measured at amortized cost - (10%)	79,891
Time Customer Deposits [Member]
IfrsStatementLineItems [Line Items]
Financial liabilities measured at amortized cost	(8,025,775)	(5,444,101)
Financial liabilities measured at amortized cost - 10%	(109,627)	(62,669)
Financial liabilities measured at amortized cost - (10%)	109,627	62,669
Debt Issued And Other Borrowed Funds [Member]
IfrsStatementLineItems [Line Items]
Financial liabilities measured at amortized cost	(530,311)	(269,173)
Financial liabilities measured at amortized cost - 10%	(6,877)	(2,916)
Financial liabilities measured at amortized cost - (10%)	6,877	2,916
Time Customer Deposits One [Member]
IfrsStatementLineItems [Line Items]
Financial liabilities measured at amortized cost	(4,368,545)	(4,486,875)
Financial liabilities measured at amortized cost - 10%	(18,133)	(20,673)
Financial liabilities measured at amortized cost - (10%)	18,133	20,673
Funds From Acceptances And Issuance Of Securities One [Member]
IfrsStatementLineItems [Line Items]
Financial liabilities measured at amortized cost	(17,588)
Financial liabilities measured at amortized cost - 10%	176
Financial liabilities measured at amortized cost - (10%)	(176)
Time Customer Deposits Two [Member]
IfrsStatementLineItems [Line Items]
Financial liabilities measured at amortized cost	(8,110,561)	(6,325,758)
Financial liabilities measured at amortized cost - 10%	87,870	63,872
Financial liabilities measured at amortized cost - (10%)	(87,870)	(63,872)
Loans And Borrowing [Member]
IfrsStatementLineItems [Line Items]
Financial liabilities measured at amortized cost	(667,089)	(480,103)
Financial liabilities measured at amortized cost - 10%	(8,651)	(5,201)
Financial liabilities measured at amortized cost - (10%)	8,651	5,201
Debt Issued And Other Borrowed Funds One [Member]
IfrsStatementLineItems [Line Items]
Financial liabilities measured at amortized cost	(229,027)	(253,109)
Financial liabilities measured at amortized cost - 10%	2,761	2,825
Financial liabilities measured at amortized cost - (10%)	(2,761)	(2,825)
Repurchase Agrements [Member]
IfrsStatementLineItems [Line Items]
Financial liabilities measured at amortized cost	(3,251,446)	(6,221)
Financial liabilities measured at amortized cost - 10%	(42,164)	59
Financial liabilities measured at amortized cost - (10%)	R$ 42,164	(59)
Securities Financial Treasury Bills [Member]
IfrsStatementLineItems [Line Items]
Financial assets measured at fair value through other comprehensive income		14,394
Financial assets measured at fair value through other comprehensive income - 10%		156
Financial assets measured at fair value through other comprehensive income - (10%)		(156)
Exchange Acceptance Resources [Member]
IfrsStatementLineItems [Line Items]
Financial liabilities measured at amortized cost		(3,227,072)
Financial liabilities measured at amortized cost - 10%		(35,035)
Financial liabilities measured at amortized cost - (10%)		35,035
Exchange Acceptance Resources One [Member]
IfrsStatementLineItems [Line Items]
Financial liabilities measured at amortized cost		(28,913)
Financial liabilities measured at amortized cost - 10%		278
Financial liabilities measured at amortized cost - (10%)		R$ (278)

Represents the financial asset at amortised cost.

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- Definition

Represents the financial assets decrease in interest change scenario.

+ References

No definition available.

+ Details

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Data Type:	xbrli:monetaryItemType
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- Definition

Represents the financial assets fair value decrease in interest change scenario.

+ References

No definition available.

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Represents the financial assets fair value increase interest change scenario.

+ References

No definition available.

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Data Type:	xbrli:monetaryItemType
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- Definition

Represents the financial assets increase in interest change scenario.

+ References

No definition available.

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- Definition

Represents the financial assets other comprehensive income decrease in interest change scenario.

+ References

No definition available.

+ Details

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- Definition

Represents the financial assets other comprehensive income increase in interest change scenario.

+ References

No definition available.

+ Details

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Data Type:	xbrli:monetaryItemType
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- Definition

Represents the financial liabilities decrease interest change scenario.

+ References

No definition available.

+ Details

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- Definition

Represents the financial liabilities increase interest change scenario.

+ References

No definition available.

+ Details

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- Definition

Represents the financial liabilities measured at amortized cost.

+ References

No definition available.

+ Details

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Namespace Prefix:	AGBK_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- References

No definition available.

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- Definition

Represents the obligations related to credit assignments.

+ References

No definition available.

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Represents the obligations related to credit assignments decrease interest change scenario.

+ References

No definition available.

+ Details

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Data Type:	xbrli:monetaryItemType
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- Definition

Represents the obligations related to credit assignments increase interest change scenario.

+ References

No definition available.

+ Details

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Data Type:	xbrli:monetaryItemType
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- Definition

Represents the other liabilities decrease interest change scenario.

+ References

No definition available.

+ Details

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Data Type:	xbrli:monetaryItemType
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- Definition

Represents the other liabilities increase interest change scenario.

+ References

No definition available.

+ Details

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Data Type:	xbrli:monetaryItemType
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- Definition

Represents the other liabilities increase interest changes scenario.

+ References

No definition available.

+ Details

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- Definition

The amount of financial assets mandatorily measured at fair value through profit or loss in accordance with IFRS 9. [Refer: Financial assets at fair value through profit or loss]

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name IFRS
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-IssueDate 2024-01-01
-Paragraph 8
-Subparagraph a
-URI https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2024-en-r&anchor=para_8_a&doctype=Standard
-URIDate 2024-03-27

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- Definition

The amount of financial assets that are measured at fair value through other comprehensive income. A financial asset shall be measured at fair value through other comprehensive income if both of the following conditions are met: (a) the financial asset is held within a business model whose objective is achieved by both collecting contractual cash flows and selling financial assets and (b) the contractual terms of the financial asset give rise on specified dates to cash flows that are solely payments of principal and interest on the principal amount outstanding. [Refer: At fair value [member]; Financial assets]

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name IFRS
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-Paragraph 8
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-URI https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2024-en-r&anchor=para_8_h&doctype=Standard
-URIDate 2024-03-27

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