CASH COLLATERAL, REVERSE REPURCHASE AGREEMENTS AND SECURITIES BORROWING AND PAYABLES FROM REPURCHASE AGREEMENTS AND SECURITIES LENDING - Repurchase agreements (Details) - PEN (S/)
S/ in Thousands
 12 Months Ended
Dec. 31, 2019
Dec. 31, 2018
Jan. 01, 2018
Disclosure of Cash Collateral, Reverse Repurchase Agreements And Securities Borrowings And Payables From Repurchase Agreements And Security Lendings [Line Items]      
Financial liabilities     S/ 139,747,905
Debt instruments [Member]      
Disclosure of Cash Collateral, Reverse Repurchase Agreements And Securities Borrowings And Payables From Repurchase Agreements And Security Lendings [Line Items]      
Financial liabilities S/ 6,331,465 S/ 7,944,790  
BCRP one [Member] | Debt instruments [Member]      
Disclosure of Cash Collateral, Reverse Repurchase Agreements And Securities Borrowings And Payables From Repurchase Agreements And Security Lendings [Line Items]      
Description of presentation currency Soles    
Borrowings, maturity February 2020 / October 2020 January 2019 / November 2019  
Financial liabilities S/ 2,800,400 S/ 2,948,500  
Description of collateral held as security and other credit enhancements Cash with BCRP Cash with BCRP  
BCRP two [Member] | Debt instruments [Member]      
Disclosure of Cash Collateral, Reverse Repurchase Agreements And Securities Borrowings And Payables From Repurchase Agreements And Security Lendings [Line Items]      
Description of presentation currency Soles    
Borrowings, maturity June 2020 / November 2020 January 2019 / November 2020  
Financial liabilities S/ 1,504,088 S/ 2,220,265  
Description of collateral held as security and other credit enhancements Investments Investments  
Natixis SA one [Member] | Debt instruments [Member]      
Disclosure of Cash Collateral, Reverse Repurchase Agreements And Securities Borrowings And Payables From Repurchase Agreements And Security Lendings [Line Items]      
Description of presentation currency Soles    
Borrowings, maturity August 2020 / August 2028 August 2020 / August 2028  
Financial liabilities S/ 570,000 S/ 570,000  
Description of collateral held as security and other credit enhancements Investments Investments  
Banco Central de Bolivia [Member] | Debt instruments [Member]      
Disclosure of Cash Collateral, Reverse Repurchase Agreements And Securities Borrowings And Payables From Repurchase Agreements And Security Lendings [Line Items]      
Description of presentation currency Bolivianos    
Borrowings, maturity May 2020 / February 2021 May 2019  
Financial liabilities S/ 398,586 S/ 89,941  
Description of collateral held as security and other credit enhancements Cash Cash  
Nomura International PLC two [Member] | Debt instruments [Member]      
Disclosure of Cash Collateral, Reverse Repurchase Agreements And Securities Borrowings And Payables From Repurchase Agreements And Security Lendings [Line Items]      
Description of presentation currency [1] U.S. Dollar    
Borrowings, maturity [1] August 2020 August 2020  
Financial liabilities [1] S/ 265,120 S/ 269,840  
Description of collateral held as security and other credit enhancements [1] Investments and cash Investments and cash  
Nomura International PLC three [Member] | Debt instruments [Member]      
Disclosure of Cash Collateral, Reverse Repurchase Agreements And Securities Borrowings And Payables From Repurchase Agreements And Security Lendings [Line Items]      
Description of presentation currency U.S. Dollar    
Borrowings, maturity August 2020 August 2020  
Financial liabilities S/ 231,980 S/ 236,110  
Description of collateral held as security and other credit enhancements Investments and cash Investments and cash  
Citigroup Global Markets Limited one [Member] | Debt instruments [Member]      
Disclosure of Cash Collateral, Reverse Repurchase Agreements And Securities Borrowings And Payables From Repurchase Agreements And Security Lendings [Line Items]      
Description of presentation currency U.S. Dollar    
Borrowings, maturity August 2026 August 2026  
Financial liabilities S/ 149,130 S/ 151,785  
Description of collateral held as security and other credit enhancements Investments Investments  
Citigroup Global Markets Limited two [Member] | Debt instruments [Member]      
Disclosure of Cash Collateral, Reverse Repurchase Agreements And Securities Borrowings And Payables From Repurchase Agreements And Security Lendings [Line Items]      
Description of presentation currency Soles    
Borrowings, maturity August 2020 August 2020  
Financial liabilities S/ 100,000 S/ 100,000  
Description of collateral held as security and other credit enhancements Investments Investments  
Natixis S.A Five [Member] | Debt instruments [Member]      
Disclosure of Cash Collateral, Reverse Repurchase Agreements And Securities Borrowings And Payables From Repurchase Agreements And Security Lendings [Line Items]      
Description of presentation currency U.S. Dollar    
Borrowings, maturity August 2026 August 2026  
Financial liabilities S/ 82,850 S/ 84,325  
Description of collateral held as security and other credit enhancements Investments Investments  
Banco De Le Republica [Member] | Debt instruments [Member]      
Disclosure of Cash Collateral, Reverse Repurchase Agreements And Securities Borrowings And Payables From Repurchase Agreements And Security Lendings [Line Items]      
Description of presentation currency Colombian pesos    
Borrowings, maturity January 2020 January 2019  
Financial liabilities S/ 64,540 S/ 42,607  
Description of collateral held as security and other credit enhancements Investments Investments  
Nomura International PLC five [Member] | Debt instruments [Member]      
Disclosure of Cash Collateral, Reverse Repurchase Agreements And Securities Borrowings And Payables From Repurchase Agreements And Security Lendings [Line Items]      
Description of presentation currency U.S. Dollar    
Borrowings, maturity - March 2019 / December 2019  
Financial liabilities   S/ 505,950  
Description of collateral held as security and other credit enhancements - Investments  
Natixis [Member] | Debt instruments [Member]      
Disclosure of Cash Collateral, Reverse Repurchase Agreements And Securities Borrowings And Payables From Repurchase Agreements And Security Lendings [Line Items]      
Description of presentation currency U.S. Dollar    
Borrowings, maturity - January 2019 / March 2019  
Financial liabilities   S/ 566,962  
Description of collateral held as security and other credit enhancements - Investments  
Others | Debt instruments [Member]      
Disclosure of Cash Collateral, Reverse Repurchase Agreements And Securities Borrowings And Payables From Repurchase Agreements And Security Lendings [Line Items]      
Description of presentation currency -    
Borrowings, maturity January 2020 / April 2033 January 2019 / October 2033  
Financial liabilities S/ 64,970 S/ 70,298  
Description of collateral held as security and other credit enhancements Investments Investments  
Accrued Interest [Member] | Debt instruments [Member]      
Disclosure of Cash Collateral, Reverse Repurchase Agreements And Securities Borrowings And Payables From Repurchase Agreements And Security Lendings [Line Items]      
Financial liabilities S/ 99,801 S/ 88,207  
[1] (i)    At December 31, 2019, the Group maintains an IRS and a CCS which were together designated as a cash flow hedge of a repurchase agreement in U.S. Dollars at variable rate for a notional amount of US$80.0 million, equivalent to S/265.1 million (approximately US$80.0 million, equivalent to S/269.8 million, at December 31, 2018). By means of the IRS and the CCS, said repurchase agreement was economically converted to soles at fixed interest rate; see note 13(b).