RISK MANAGEMENT - Participation for loan portfolio in foreign currency (Details) $ in Millions	12 Months Ended
Dec. 31, 2019 USD ($)
Disclosure of risk management [abstract]
Percentage of maximum participation of dollar for loan portfolio in foreign currency	37.90%
Value of dollars in maximum participation for loan portfolio in foreign currency	$ 21,084

Percentage of maximum participation of dollar for loan portfolio in foreign currency.

No definition available.

Name:	aval_PercentageOfMaximumParticipationOfDollarForLoanPortfolioInForeignCurrency
Namespace Prefix:	aval_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration