Quarterly report pursuant to Section 13 or 15(d)

Derivative Instruments and Hedging Activities Schedule of Interest Rate Swap Receivers (Details)

v3.7.0.1
Derivative Instruments and Hedging Activities Schedule of Interest Rate Swap Receivers (Details) - USD ($)
$ in Thousands
 3 Months Ended 12 Months Ended
Mar. 31, 2017
Dec. 31, 2016
Mar. 31, 2016
Dec. 31, 2015
Derivative [Line Items]        
Derivative, Notional Amount $ 15,935,535 $ 18,802,500 $ 26,390,596 $ 21,998,381
Interest Rate Swap [Member]        
Derivative [Line Items]        
Derivative, Notional Amount 18,252,440 20,371,063 $ 15,425,513 $ 14,268,806
Interest Rate Swap [Member] | Short [Member]        
Derivative [Line Items]        
Derivative, Notional Amount $ 4,162,856 $ 5,064,000    
Derivative, Average Variable Interest Rate 1.062% 0.941%    
Derivative, Average Fixed Interest Rate 1.863% 1.894%    
Derivative, Average Remaining Maturity 4 years 7 months 18 days 4 years 6 months 27 days    
Interest Rate Swap [Member] | Derivative Maturity Over One And Within Two Years From Balance Sheet Date [Member] | Short [Member]        
Derivative [Line Items]        
Derivative, Notional Amount $ 575,000 $ 575,000    
Derivative, Average Variable Interest Rate 1.052% 0.911%    
Derivative, Average Fixed Interest Rate 1.44% 1.44%    
Derivative, Average Remaining Maturity 1 year 7 months 21 days 1 year 10 months 21 days    
Interest Rate Swap [Member] | Derivative Maturity Over Two And Within Three Years From Balance Sheet Date [Member] | Short [Member]        
Derivative [Line Items]        
Derivative, Notional Amount $ 500,000 $ 500,000    
Derivative, Average Variable Interest Rate 1.041% 0.882%    
Derivative, Average Fixed Interest Rate 1.042% 1.042%    
Derivative, Average Remaining Maturity 1 year 9 months 22 days 2 years 22 days    
Interest Rate Swap [Member] | Derivative Maturity Over Three And Within Four Years From Balance Sheet Date [Member] | Short [Member]        
Derivative [Line Items]        
Derivative, Notional Amount $ 510,000 $ 510,000    
Derivative, Average Variable Interest Rate 1.034% 0.881%    
Derivative, Average Fixed Interest Rate 1.58% 1.58%    
Derivative, Average Remaining Maturity 3 years 4 months 4 days 3 years 7 months 4 days    
Interest Rate Swap [Member] | Derivative Maturity Over Four Years From Balance Sheet Date [Member] | Short [Member]        
Derivative [Line Items]        
Derivative, Notional Amount $ 2,577,856 $ 3,479,000    
Derivative, Average Variable Interest Rate 1.073% 0.963%    
Derivative, Average Fixed Interest Rate 2.173% 2.137%    
Derivative, Average Remaining Maturity 6 years 1 month 8 days 5 years 6 months 8 days