DERIVATIVES - Schedule of Fair Value Hedges (Details) - Interest rate swap - USD ($) $ in Millions	3 Months Ended	6 Months Ended
Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Interest expense - borrowed funds
Derivative Instruments, Gain (Loss) [Line Items]
Derivative	$ 5	$ 64	$ 98	$ 104
Hedged Item	(3)	(64)	(95)	(103)
Interest and fees on loans and leases
Derivative Instruments, Gain (Loss) [Line Items]
Derivative	0	(16)	17	(16)
Hedged Item	0	16	(17)	16
Interest income - investment securities
Derivative Instruments, Gain (Loss) [Line Items]
Derivative	(14)	0	(121)	0
Hedged Item	$ 14	$ 0	$ 121	$ 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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