FINANCIAL INSTRUMENTS CLASSIFICATION (Details) - PEN (S/)
S/ in Thousands
Dec. 31, 2019
Jan. 01, 2019
Dec. 31, 2018
Jan. 01, 2018
Dec. 31, 2017
Jan. 01, 2017
Assets [Abstract]            
Cash and due from banks S/ 25,986,762   S/ 22,168,516      
Guarantee funds, reverse repurchase agreements and securities borrowings 4,288,524   4,082,942 S/ 7,480,420    
At fair value through profit or loss 620,544   521,186      
Investments at fair value through other comprehensive income, Note 6(b) 26,202,723   25,195,835      
Available-for-sale investments 25,370,413   24,331,543      
Amortized cost investments 1,907,738   1,292,203      
Loans 110,485,717   105,806,998      
Financial assets designated at fair value through profit or loss 179,870,703   171,212,821      
Premiums and other policies receivable 838,731   887,273      
Accounts receivable from reinsurers and coinsurers 791,704   842,043      
Due from customers on acceptances 535,222   967,968      
Other assets, Note 13(a) 2,792,968   3,072,777      
Liabilities [Abstract]            
Deposits and obligations 112,005,385   104,551,310      
Payables from repurchase agreements and security lendings 7,678,016   9,415,357      
Due to banks and correspondents 8,841,732   8,448,140      
Bankers' acceptances outstanding 535,222   967,968      
Accounts payable to reinsurers and coinsurers 216,734 S/ 291,693 291,693 S/ 235,185 S/ 235,185 S/ 233,892
Lease liabilities 847,504 S/ 852,800 0      
Financial liabilities at fair value through profit or loss 493,700   362,310      
Bonds and Notes issued 14,946,363   15,457,540      
Other liabilities, Note 13(a) 4,246,826   3,694,318      
Categories of Financial Position [Member]            
Assets [Abstract]            
Cash and due from banks 25,986,762   22,168,516      
Guarantee funds, reverse repurchase agreements and securities borrowings 4,288,524   4,082,942      
At fair value through profit or loss 3,850,762   3,512,445      
Investments at fair value through other comprehensive income, Note 6(b) 26,202,723   25,195,835      
Amortized cost investments 3,477,046   4,154,838      
Loans 110,485,717   105,806,998      
Financial assets designated at fair value through profit or loss 620,544   521,186      
Premiums and other policies receivable 838,731   887,273      
Accounts receivable from reinsurers and coinsurers 791,704   842,043      
Due from customers on acceptances 535,222   967,968      
Other assets, Note 13(a) 2,792,968   3,072,777      
Financial assets, at fair value 179,870,703   171,212,821      
Liabilities [Abstract]            
Deposits and obligations 112,005,385   104,551,310      
Payables from repurchase agreements and security lendings 7,678,016   9,415,357      
Due to banks and correspondents 8,841,732   8,448,140      
Bankers' acceptances outstanding 535,222   967,968      
Accounts payable to reinsurers and coinsurers 216,734   291,693      
Lease liabilities 847,504          
Financial liabilities at fair value through profit or loss 493,700   362,310      
Bonds and Notes issued 14,946,363   15,457,540      
Other liabilities, Note 13(a) 4,246,826   3,694,318      
Financial liabilities, at fair value 149,811,482   143,188,636      
Financial assets at fair value through profit or loss, classified as held for trading, category [Member]            
Assets [Abstract]            
Financial assets designated at fair value through profit or loss [1] 4,942,869   4,278,762      
Financial assets at fair value through profit or loss, classified as held for trading, category [Member] | Categories of Financial Position [Member]            
Assets [Abstract]            
Cash and due from banks 0   0      
Guarantee funds, reverse repurchase agreements and securities borrowings 0   0      
At fair value through profit or loss 3,850,762   3,512,445      
Investments at fair value through other comprehensive income, Note 6(b) 0   0      
Amortized cost investments 0   0      
Loans 0   0      
Financial assets designated at fair value through profit or loss 0   0      
Premiums and other policies receivable 0   0      
Accounts receivable from reinsurers and coinsurers 0   0      
Due from customers on acceptances 0   0      
Other assets, Note 13(a) 1,092,107   766,317      
Financial assets, at fair value 4,942,869   4,278,762      
Liabilities [Abstract]            
Deposits and obligations 0   0      
Payables from repurchase agreements and security lendings 0   0      
Due to banks and correspondents 0   0      
Bankers' acceptances outstanding 0   0      
Accounts payable to reinsurers and coinsurers 0   0      
Lease liabilities 0   0      
Financial liabilities at fair value through profit or loss 493,700   362,310      
Bonds and Notes issued 0   0      
Other liabilities, Note 13(a) 1,040,282   715,804      
Financial liabilities, at fair value 1,533,982   1,078,114      
Designated at inception            
Assets [Abstract]            
Financial assets designated at fair value through profit or loss 620,544   521,186      
Designated at inception | Categories of Financial Position [Member]            
Assets [Abstract]            
Cash and due from banks 0   0      
Guarantee funds, reverse repurchase agreements and securities borrowings 0   0      
At fair value through profit or loss 0   0      
Investments at fair value through other comprehensive income, Note 6(b) 0   0      
Amortized cost investments 0   0      
Loans 0   0      
Financial assets designated at fair value through profit or loss 620,544   521,186      
Premiums and other policies receivable 0   0      
Accounts receivable from reinsurers and coinsurers 0   0      
Due from customers on acceptances 0   0      
Other assets, Note 13(a) 0   0      
Financial assets, at fair value 620,544   521,186      
Liabilities [Abstract]            
Deposits and obligations 0   0      
Payables from repurchase agreements and security lendings 0   0      
Due to banks and correspondents 0   0      
Bankers' acceptances outstanding 0   0      
Accounts payable to reinsurers and coinsurers 0   0      
Lease liabilities 0   0      
Financial liabilities at fair value through profit or loss 0   0      
Bonds and Notes issued 0   0      
Other liabilities, Note 13(a) 0   0      
Financial liabilities, at fair value 0   0      
At fair value through other comprehensive income [Member] | Categories of Financial Position [Member]            
Assets [Abstract]            
Cash and due from banks 0   0      
Guarantee funds, reverse repurchase agreements and securities borrowings 0   0      
At fair value through profit or loss 0   0      
Investments at fair value through other comprehensive income, Note 6(b) 25,623,934   24,546,365      
Amortized cost investments 0   0      
Loans 0   0      
Financial assets designated at fair value through profit or loss 0   0      
Premiums and other policies receivable 0   0      
Accounts receivable from reinsurers and coinsurers 0   0      
Due from customers on acceptances 0   0      
Other assets, Note 13(a) 0   0      
Financial assets, at fair value 25,623,934   24,546,365      
Liabilities [Abstract]            
Deposits and obligations 0   0      
Payables from repurchase agreements and security lendings 0   0      
Due to banks and correspondents 0   0      
Bankers' acceptances outstanding 0   0      
Accounts payable to reinsurers and coinsurers 0   0      
Lease liabilities 0   0      
Financial liabilities at fair value through profit or loss 0   0      
Bonds and Notes issued 0   0      
Other liabilities, Note 13(a) 0   0      
Financial liabilities, at fair value 0   0      
At fair value through other comprehensive income (Debt instruments)            
Assets [Abstract]            
Financial assets designated at fair value through profit or loss 26,202,723   25,195,835      
At fair value through other comprehensive income (Debt instruments) | Categories of Financial Position [Member]            
Assets [Abstract]            
Cash and due from banks 0   0      
Guarantee funds, reverse repurchase agreements and securities borrowings 0   0      
At fair value through profit or loss 0   0      
Investments at fair value through other comprehensive income, Note 6(b) 578,789   649,470      
Amortized cost investments 0   0      
Loans 0   0      
Financial assets designated at fair value through profit or loss 0   0      
Premiums and other policies receivable 0   0      
Accounts receivable from reinsurers and coinsurers 0   0      
Due from customers on acceptances 0   0      
Other assets, Note 13(a) 0   0      
Financial assets, at fair value 578,789   649,470      
Liabilities [Abstract]            
Deposits and obligations 0   0      
Payables from repurchase agreements and security lendings 0   0      
Due to banks and correspondents 0   0      
Bankers' acceptances outstanding 0   0      
Accounts payable to reinsurers and coinsurers 0   0      
Lease liabilities 0   0      
Financial liabilities at fair value through profit or loss 0   0      
Bonds and Notes issued 0   0      
Other liabilities, Note 13(a) 0   0      
Financial liabilities, at fair value 0   0      
Financial Assets And Liabilities At Amortised Cost Category [Member] | Categories of Financial Position [Member]            
Assets [Abstract]            
Cash and due from banks 25,986,762   22,168,516      
Guarantee funds, reverse repurchase agreements and securities borrowings 4,288,524   4,082,942      
At fair value through profit or loss 0   0      
Investments at fair value through other comprehensive income, Note 6(b) 0   0      
Amortized cost investments 3,477,046   4,154,838      
Loans 110,485,717   105,806,998      
Financial assets designated at fair value through profit or loss 0   0      
Premiums and other policies receivable 838,731   887,273      
Accounts receivable from reinsurers and coinsurers 791,704   842,043      
Due from customers on acceptances 535,222   967,968      
Other assets, Note 13(a) 1,700,861   2,306,460      
Financial assets, at fair value 148,104,567   141,217,038      
Liabilities [Abstract]            
Deposits and obligations 112,005,385   104,551,310      
Payables from repurchase agreements and security lendings 7,678,016   9,415,357      
Due to banks and correspondents 8,841,732   8,448,140      
Bankers' acceptances outstanding 535,222   967,968      
Accounts payable to reinsurers and coinsurers 216,734   291,693      
Lease liabilities 847,504   0      
Financial liabilities at fair value through profit or loss 0   0      
Bonds and Notes issued 14,946,363   15,457,540      
Other liabilities, Note 13(a) 3,206,544   2,978,514      
Financial liabilities, at fair value S/ 148,277,500   S/ 142,110,522      
[1] It includes non-trading investments that did not pass SPPI test.