LOANS AND LEASES - Impaired Loans and Lease (Detail) - Originated Loans and Leases [Member] - USD ($) $ in Millions	6 Months Ended	12 Months Ended
Jun. 30, 2019	Dec. 31, 2018
Financial Receivables Impaired Or Restructured [Line Items]
Unpaid Contractual Principal Balance	$ 102	$ 113
Recorded Investment With No Specific Reserve	75	73
Recorded Investment With Specific Reserve	6	14
Total Recorded Investment	81	87
Specific Reserve	3	4
Average Recorded Investment	79	90
Commercial Real Estate [Member]
Financial Receivables Impaired Or Restructured [Line Items]
Unpaid Contractual Principal Balance	31	20
Recorded Investment With No Specific Reserve	21	16
Recorded Investment With Specific Reserve	6	1
Total Recorded Investment	27	17
Specific Reserve	2	0
Average Recorded Investment	24	18
Commercial and Industrial [Member]
Financial Receivables Impaired Or Restructured [Line Items]
Unpaid Contractual Principal Balance	22	46
Recorded Investment With No Specific Reserve	15	20
Recorded Investment With Specific Reserve	0	13
Total Recorded Investment	15	33
Specific Reserve	1	4
Average Recorded Investment	17	32
Commercial Leases [Member]
Financial Receivables Impaired Or Restructured [Line Items]
Unpaid Contractual Principal Balance	2	2
Recorded Investment With No Specific Reserve	2	2
Recorded Investment With Specific Reserve	0	0
Total Recorded Investment	2	2
Specific Reserve	0	0
Average Recorded Investment	2	4
Total Commercial Loans and Leases [Member]
Financial Receivables Impaired Or Restructured [Line Items]
Unpaid Contractual Principal Balance	55	68
Recorded Investment With No Specific Reserve	38	38
Recorded Investment With Specific Reserve	6	14
Total Recorded Investment	44	52
Specific Reserve	3	4
Average Recorded Investment	43	54
Direct Installment [Member]
Financial Receivables Impaired Or Restructured [Line Items]
Unpaid Contractual Principal Balance	17	17
Recorded Investment With No Specific Reserve	14	14
Recorded Investment With Specific Reserve	0	0
Total Recorded Investment	14	14
Specific Reserve	0	0
Average Recorded Investment	14	14
Residential Mortgages [Member]
Financial Receivables Impaired Or Restructured [Line Items]
Unpaid Contractual Principal Balance	18	16
Recorded Investment With No Specific Reserve	16	14
Recorded Investment With Specific Reserve	0	0
Total Recorded Investment	16	14
Specific Reserve	0	0
Average Recorded Investment	15	15
Indirect Installment [Member]
Financial Receivables Impaired Or Restructured [Line Items]
Unpaid Contractual Principal Balance	5	5
Recorded Investment With No Specific Reserve	2	2
Recorded Investment With Specific Reserve	0	0
Total Recorded Investment	2	2
Specific Reserve	0	0
Average Recorded Investment	2	2
Consumer Lines of Credit [Member]
Financial Receivables Impaired Or Restructured [Line Items]
Unpaid Contractual Principal Balance	7	7
Recorded Investment With No Specific Reserve	5	5
Recorded Investment With Specific Reserve	0	0
Total Recorded Investment	5	5
Specific Reserve	0	0
Average Recorded Investment	5	5
Consumer Loan [Member]
Financial Receivables Impaired Or Restructured [Line Items]
Unpaid Contractual Principal Balance	47	45
Recorded Investment With No Specific Reserve	37	35
Recorded Investment With Specific Reserve	0	0
Total Recorded Investment	37	35
Specific Reserve	0	0
Average Recorded Investment	$ 36	$ 36

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Average amount of investment of impaired financing receivables with related allowance for credit losses and without a related allowance for credit losses.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 15
-Subparagraph (c)(1)
-URI http://asc.fasb.org/extlink&oid=118936363&loc=d3e5212-111524

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-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 17
-URI http://asc.fasb.org/extlink&oid=118936363&loc=d3e5258-111524

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-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 14A
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=118936363&loc=SL6953550-111524

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