CASH COLLATERAL, REVERSE REPURCHASE AGREEMENTS AND SECURITIES BORROWING AND PAYABLES FROM REPURCHASE AGREEMENTS AND SECURITIES LENDING - Composition of cash collateral, reverse repurchase agreements and securities borrowing (Details) - PEN (S/) S/ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Disclosure of Cash Collateral, Reverse Repurchase Agreements And Securities Borrowings And Payables From Repurchase Agreements And Security Lendings [Line Items]
Reverse repurchase agreements and cash collateral on securities borrowed	S/ 2,394,302	S/ 4,288,524
Cash collateral on repurchase agreements and security lendings [Member]
Disclosure of Cash Collateral, Reverse Repurchase Agreements And Securities Borrowings And Payables From Repurchase Agreements And Security Lendings [Line Items]
Reverse repurchase agreements and cash collateral on securities borrowed	1,601,200	3,293,837
Reverse repurchase agreement and security borrowings [Member]
Disclosure of Cash Collateral, Reverse Repurchase Agreements And Securities Borrowings And Payables From Repurchase Agreements And Security Lendings [Line Items]
Reverse repurchase agreements and cash collateral on securities borrowed	626,925	899,435
Receivables for short sales [Member]
Disclosure of Cash Collateral, Reverse Repurchase Agreements And Securities Borrowings And Payables From Repurchase Agreements And Security Lendings [Line Items]
Reverse repurchase agreements and cash collateral on securities borrowed	S/ 166,177	S/ 95,252