MORTGAGE BANKING AND OTHER - Narrative (Details) - USD ($) $ in Millions	Jun. 30, 2021	Dec. 31, 2020
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases	$ 122,581	$ 123,090
Mortgage loans serviced for others \| Banking Subsidiaries
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases	$ 84,600	$ 81,200

Amount, before allowance for credit loss, of financing receivable.

Reference 1: http://www.xbrl.org/2003/role/exampleRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 326
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-Section 55
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Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 326
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-Section 50
-Paragraph 5
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Reference 3: http://www.xbrl.org/2003/role/exampleRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 326
-SubTopic 20
-Section 55
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