RISK MANAGEMENT - Loss allowance related with CRDS (Details) - COP ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018
Disclosure Of Financial Risk Management Explanatory [Line Items]
Exposure amount	$ 280,166,274	$ 265,822,388
CRDS
Disclosure Of Financial Risk Management Explanatory [Line Items]
Percentage of exposure	100.00%
Exposure amount	$ 761,993

Represents the information pertaining to disclosure of financial risk management explanatory line items.

No definition available.

Name:	aval_DisclosureOfFinancialRiskManagementExplanatoryLineItems
Namespace Prefix:	aval_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

The rate of expected credit losses, calculated as percentage of the gross carrying amount. Expected credit losses are the weighted average of credit losses with the respective risks of a default occurring as the weights.

+ References

Reference 1: http://www.xbrl.org/2003/role/exampleRef
-Name IFRS
-Number 7
-IssueDate 2019-01-01
-Paragraph IG20D
-URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2019-en-r&anchor=para_IG20D&doctype=Implementation%20Guidance
-URIDate 2019-03-27

Reference 2: http://www.xbrl.org/2003/role/exampleRef
-Name IFRS
-Number 7
-IssueDate 2019-01-01
-Paragraph 35N
-URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2019-en-r&anchor=para_35N&doctype=Standard
-URIDate 2019-03-27

+ Details

Name:	ifrs-full_ExpectedCreditLossRate
Namespace Prefix:	ifrs-full_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

The amount that best represents the maximum exposure to credit risk without taking into account any collateral held or other credit enhancements (for example, netting agreements that do not qualify for offset in accordance with IAS 32). [Refer: Credit risk [member]]

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name IFRS
-Number 7
-IssueDate 2019-01-01
-Paragraph 35K
-Subparagraph a
-URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2019-en-r&anchor=para_35K_a&doctype=Standard
-URIDate 2019-03-27

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Note Expiry date 2021-01-01
-Name IFRS
-Number 7
-IssueDate 2019-01-01
-Paragraph 36
-Subparagraph a
-URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2017-en-b&anchor=para_36_a&doctype=Standard&book=b
-URIDate 2019-03-27

+ Details

Name:	ifrs-full_MaximumExposureToCreditRisk
Namespace Prefix:	ifrs-full_
Data Type:	xbrli:monetaryItemType
Balance Type:	na
Period Type:	instant

- Details

Name:	ifrs-full_CategoriesOfRelatedPartiesAxis=aval_ConcesionariaRutaDelSolS.a.sMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: