ALLOWANCE FOR CREDIT LOSSES, NONPERFORMING ASSETS, AND CONCENTRATIONS OF CREDIT RISK - Recorded Investment in Loan and Leases (Details) - USD ($) $ in Millions	Dec. 31, 2018	Dec. 31, 2017
Financing Receivable, Recorded Investment [Line Items]
Individually evaluated	$ 1,114	$ 1,131
Formula-based evaluation	115,546	109,486
Total loans and leases	116,660	110,617
Commercial
Financing Receivable, Recorded Investment [Line Items]
Individually evaluated	391	370
Formula-based evaluation	56,392	51,661
Total loans and leases	56,783	52,031
Retail
Financing Receivable, Recorded Investment [Line Items]
Individually evaluated	723	761
Formula-based evaluation	59,154	57,825
Total loans and leases	$ 59,877	$ 58,586

The balance of financing receivables that were collectively evaluated for impairment.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 11B
-Subparagraph (h)
-URI http://asc.fasb.org/extlink&oid=84173941&loc=SL6953423-111524

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- Definition

The balance of financing receivables that were individually evaluated for impairment.

+ References

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- Definition

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+ References

No definition available.

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Net amount of the investment in a contractual right to receive money on demand or on fixed or determinable dates that is recognized as an asset in the creditor's statement of financial position. Examples include, but are not limited to, credit card receivables, notes receivable and receivables relating to lessor's rights to payments from leases other than operating leases that have been recorded as assets. Excludes trade accounts receivable with contractual maturity of one year or less and arose from the sale of goods or services.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.3)
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

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