DERIVATIVES - Schedule of Fair Value Hedges (Details) - Interest rate swap - USD ($) $ in Millions	3 Months Ended	9 Months Ended
Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Interest expense - borrowed funds
Derivative Instruments, Gain (Loss) [Line Items]
Derivative	$ 18	$ (6)	$ 122	$ (32)
Hedged Item	(18)	7	(121)	31
Interest and fees on loans and leases
Derivative Instruments, Gain (Loss) [Line Items]
Derivative	(10)	0	(26)	0
Hedged Item	10	0	26	0
Interest income - investment securities
Derivative Instruments, Gain (Loss) [Line Items]
Derivative	(13)	0	(13)	0
Hedged Item	$ 13	$ 0	$ 13	$ 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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- Definition

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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