CASH AND CASH EQUIVALENTS - Textual (Details) - COP ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018
Disclosure of cash and cash equivalents [Abstract]
Cash reserves	$ 16,806,578	$ 15,710,055

The amount of reserve that is kept in deposit at a central bank to fulfil regulatory reserve requirements.

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Name IAS
-Number 1
-IssueDate 2019-01-01
-Paragraph 112
-Subparagraph c
-URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=1&code=ifrs-tx-2019-en-r&anchor=para_112_c&doctype=Standard
-URIDate 2019-03-27

Name:	ifrs-full_MandatoryReserveDepositsAtCentralBanks
Namespace Prefix:	ifrs-full_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant