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DERIVATIVE FINANCIAL INSTRUMENTS - Asset and Liability Managemen Add Info (Details Add Info)

v3.8.0.1
DERIVATIVE FINANCIAL INSTRUMENTS - Asset and Liability Managemen Add Info (Details Add Info) - USD ($)
 9 Months Ended 12 Months Ended
Sep. 30, 2017
Dec. 31, 2016
Derivative [Line Items]    
Derivative, Notional Amount $ 9,700,000,000 $ 10,800,000,000
Additional information about the interest rate swaps used in companies Asset and Liability Management    
Notional Value $ 9,700,000,000 $ 10,800,000,000
Average Maturity (years) 2 years 4 months 2 years 4 months
Fair Value $ (60,387,000) $ (53,556,000)
Weighted-Average Rate Receive  
Weighted-Average Rate Pay  
Asset conversion swaps - Receive Fixed - Generic    
Additional information about the interest rate swaps used in companies Asset and Liability Management    
Notional Value $ 1,325,000,000 $ 3,325,000,000
Average Maturity (years) 1 month 17 days 7 months 6 days
Fair Value $ (1,239,000) $ (2,060,000)
Weighted-Average Rate Receive 0.72% 1.04%
Weighted-Average Rate Pay 1.23% 0.91%
Liability conversion swaps - Receive Fixed - Generic    
Additional information about the interest rate swaps used in companies Asset and Liability Management    
Notional Value $ 8,375,000,000 $ 7,475,000,000
Average Maturity (years) 2 years 10 months 3 years 1 month 6 days
Fair Value $ (59,148,000) $ (51,496,000)
Weighted-Average Rate Receive 1.56% 1.49%
Weighted-Average Rate Pay 1.29% 0.88%