XML 100 R73.htm IDEA: XBRL DOCUMENT v3.20.1

Significant Accounting Policies - Additional Information (Detail) - Segment	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Disclosure of accounting policies [line items]
Percentage of variation in total assets due to transition to IFRS 16	10.00%
Number of reportable segments	3
Bottom of range [member]
Disclosure of accounting policies [line items]
Consolidated companies percentage as total consolidated assets, as well as interests in their voting capital	95.00%	95.00%

X

- Definition

Aggregate percentage of consolidated companies to consolidated assets

+ References

No definition available.

+ Details

Name:	itub_AggregatePercentageOfConsolidatedCompaniesToConsolidatedAssets
Namespace Prefix:	itub_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

X

- Definition

Disclosure of accounting policies [line items]

+ References

No definition available.

+ Details

Name:	itub_DisclosureOfAccountingPoliciesLineItems
Namespace Prefix:	itub_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

X

- Definition

Number of Reportable Segments1

+ References

No definition available.

+ Details

Name:	itub_NumberOfReportableSegments1
Namespace Prefix:	itub_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

X

- Definition

Percentage of variation in total assets due to transition to IFRS 16.

+ References

No definition available.

+ Details

Name:	itub_PercentageOfVariationInTotalAssetsDueToTransitionToIFRS16
Namespace Prefix:	itub_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

X

- Details

Name:	ifrs-full_RangeAxis=ifrs-full_BottomOfRangeMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: