EMPLOYEE BENEFITS - Textual (Details)	Dec. 31, 2019
Disclosure of defined benefit plans [abstract]
Percentage of reasonably possible increase and decrease in actuarial assumption	0.50%

Represents the percentage of reasonably possible increase decrease in actuarial assumptions.

No definition available.

Name:	aval_PercentageOfReasonablyPossibleIncreaseAndDecreaseInActuarialAssumption
Namespace Prefix:	aval_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant