DERIVATIVE FINANCIAL INSTRUMENTS - Cash Flow Hedges) (Details) - USD ($) $ in Millions |
3 Months Ended | 12 Months Ended | |
---|---|---|---|
Dec. 31, 2018 |
Dec. 31, 2017 |
Dec. 31, 2016 |
|
Derivative Instruments, Gain (Loss) [Line Items] | |||
Unrealized gains (losses) on derivatives used in cash flow hedging relationships arising during the period | $ 3 | $ 2 | |
Subordinated notes | Interest expense subordinated notes and other long term debt | |||
Derivative Instruments, Gain (Loss) [Line Items] | |||
Increase or (decrease) to interest expense for derivatives designated as fair value hedges | $ 112 | (53) | (122) |
Hedged subordinated notes | Interest expense subordinated notes and other long term debt | |||
Derivative Instruments, Gain (Loss) [Line Items] | |||
Increase or (decrease) to interest expense for derivatives designated as fair value hedges | $ (104) | $ 54 | $ 112 |