LONG TERM DEBT (Details 5) (BRL) In Millions	12 Months Ended
Dec. 31, 2010	Dec. 31, 2009
Debt Instrument [Line Items]
Carrying amount (excluding debentures in treasury)	1,384	2,764
Debentures 2010 [Member]
Debt Instrument [Line Items]
Original term in years	3
Currency	R$
Carrying amount (excluding debentures in treasury)	0	1,035
Coupon (%)	0	CDI + 0.29
Maturity date	Jan.10,2010
Debentures 2012 [Member]
Debt Instrument [Line Items]
Original term in years	5
Currency	R$
Carrying amount (excluding debentures in treasury)	1,037	1,033
Coupon (%)	CDI + 0.35	CDI + 0.35
Maturity date	Jan.10,2012
Debenture Others Period [Member]
Debt Instrument [Line Items]
Currency	R$
Carrying amount (excluding debentures in treasury)	347	696
Coupon (%)	0	0
Maturity date	Other

Carrying amount of long term debentures as of the reporting date.

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

- Definition

Date when the debt instrument is scheduled to be fully repaid

+ Details

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Namespace Prefix:	itub
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Description of original term in years.

+ Details

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Namespace Prefix:	itub
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Reflects the calculation as of the balance sheet date of the average interest rate weighted by the amount of long-term debt outstanding by type or by instrument at that time.

+ Details

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Namespace Prefix:	itub
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	instant

- Definition

Description of the type of currency in which the debt instrument is required to be repaid.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 129
-Paragraph 2, 4
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Section 02
-Paragraph 22
-Article 5

+ Details

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Balance Type:	na
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- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ Details

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