ALLOWANCE FOR LOAN AND LEASE LOSSES - Schedule of Allowance for Loan and Lease Losses (Details) - USD ($) $ in Millions	3 Months Ended
Mar. 31, 2025	Mar. 31, 2024
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Allowance for loan and lease losses, beginning balance	$ 1,676	$ 1,747
Provision (benefit) for loan and lease losses	148	93
Charge-offs	(167)	(128)
Recoveries	23	25
Allowance for loan and lease losses, ending balance	1,680	1,737
Commercial
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Allowance for loan and lease losses, beginning balance	1,063	1,126
Provision (benefit) for loan and lease losses	105	59
Charge-offs	(105)	(75)
Recoveries	15	10
Allowance for loan and lease losses, ending balance	1,078	1,120
Consumer
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Allowance for loan and lease losses, beginning balance	158	166
Provision (benefit) for loan and lease losses	10	(6)
Charge-offs	(8)	(7)
Recoveries	3	2
Allowance for loan and lease losses, ending balance	163	155
SVB
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Allowance for loan and lease losses, beginning balance	455	455
Provision (benefit) for loan and lease losses	33	40
Charge-offs	(54)	(46)
Recoveries	5	13
Allowance for loan and lease losses, ending balance	$ 439	$ 462

Financing Receivable, Credit Loss, Expense

No definition available.

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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Amount excluding accrued interest, of allowance for credit loss on financing receivable. Excludes net investment in lease.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 326
-SubTopic 20
-Name Accounting Standards Codification
-Section 45
-Paragraph 1
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479344/326-20-45-1

+ Details

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- Definition

A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.

+ References

No definition available.

+ Details

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- Definition

Amount, excluding accrued interest, of increase in allowance for credit loss on financing receivable from recovery. Excludes net investment in lease.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 326
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 13
-Subparagraph (e)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479319/326-20-50-13

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Amount, excluding accrued interest, of decrease in allowance for credit loss on financing receivable from writeoff. Excludes net investment in lease.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 326
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 6
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479319/326-20-50-6

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 326
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 13
-Subparagraph (d)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479319/326-20-50-13

+ Details

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- Details

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- Details

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