DERIVATIVES - Schedule of Fair Value Hedges (Details) - Hedge of interest rate risk - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Interest expense - long-term borrowed funds
Derivative Instruments, Gain (Loss) [Line Items]
Derivative	$ 107	$ 8	$ (26)
Hedged Item	(107)	(9)	27
Interest and fees on loans and leases
Derivative Instruments, Gain (Loss) [Line Items]
Derivative	(17)	0	0
Hedged Item	17	0	0
Interest income - investment securities
Derivative Instruments, Gain (Loss) [Line Items]
Derivative	8	0	0
Hedged Item	$ (8)	$ 0	$ 0

Amount of gain (loss) from the increase (decrease) in fair value of derivative and nonderivative instruments designated as fair value hedging instruments recognized in the income statement.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 25
-Section 50
-Paragraph 1
-Subparagraph (a)(1)
-URI http://asc.fasb.org/extlink&oid=109977999&loc=d3e76258-113986

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Amount of the increase (decrease) in fair value of the hedged item in a fair value hedge recognized in the income statement.

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