Quarterly report pursuant to Section 13 or 15(d)

COMMITMENTS AND CONTINGENT LIABILITIES - Narrative (Details)

v3.5.0.2
COMMITMENTS AND CONTINGENT LIABILITIES - Narrative (Details)
 2 Months Ended 3 Months Ended 9 Months Ended 12 Months Ended
Mar. 31, 2016
lawsuit
complaint
Sep. 30, 2015
USD ($)
Sep. 30, 2016
USD ($)
lawsuit
Dec. 31, 2010
lawsuit
Dec. 31, 2015
USD ($)
Sep. 28, 2015
USD ($)
Mar. 30, 2012
USD ($)
Loss Contingencies [Line Items]              
Maturity period of majority of standby letters of credit     P2Y        
Maturity period of Commercial letters of credit     P90D        
Maturity period of forward contracts relating mortgage banking business     1 year        
Cyberco Litigation              
Loss Contingencies [Line Items]              
Number of lawsuits | lawsuit     2        
Fraudulent transfers alleged by Teleservices bankruptcy trustee             $ 73,000,000
Bankruptcy Court recommended judgment amount in Cyberco case, principal           $ 72,000,000  
Loss contingency period increase (decrease)   $ 38,000,000          
FirstMerit Merger Litigation              
Loss Contingencies [Line Items]              
Number of lawsuits | lawsuit 5     2      
Number of complaints | complaint 1            
Standby Letters of Credit              
Loss Contingencies [Line Items]              
Carrying amount of deferred revenue associated with guarantees     $ 8,000,000   $ 7,000,000    
Outstanding standby letters of credit     $ 644,470,000   511,706,000    
Percentage of Outstanding standby letters of credit collateralized     81.00%        
Commercial letters-of-credit              
Loss Contingencies [Line Items]              
Outstanding standby letters of credit     $ 14,440,000   56,119,000    
Commitments to Sell Loans              
Loss Contingencies [Line Items]              
Commitments to sell residential real estate loans     1,000,000,000   $ 659,000,000    
Risk Level, Low              
Loss Contingencies [Line Items]              
Outstanding standby letters of credit     142,000,000        
Risk Level, High              
Loss Contingencies [Line Items]              
Outstanding standby letters of credit     0        
Risk Level, Medium              
Loss Contingencies [Line Items]              
Outstanding standby letters of credit     502,000,000        
Maximum              
Loss Contingencies [Line Items]              
Aggregate range of reasonably possible losses current legal proceedings     50,000,000        
Minimum              
Loss Contingencies [Line Items]              
Aggregate range of reasonably possible losses current legal proceedings     $ 0