MORTGAGE BANKING AND OTHER - Narrative (Details) - USD ($) $ in Millions	3 Months Ended
Mar. 31, 2022	Dec. 31, 2021
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases	$ 131,305	$ 128,163
Minimum
Accounts, Notes, Loans and Financing Receivable [Line Items]
Sensitivity analysis, basis spread	10.00%
Maximum
Accounts, Notes, Loans and Financing Receivable [Line Items]
Sensitivity analysis, basis spread	20.00%
Mortgage loans serviced for others \| Banking Subsidiaries
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases	$ 92,800	$ 90,200

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

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
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Reference 3: http://www.xbrl.org/2003/role/disclosureRef
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Reference 4: http://www.xbrl.org/2009/role/commonPracticeRef
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Reference 7: http://www.xbrl.org/2003/role/disclosureRef
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Reference 8: http://www.xbrl.org/2003/role/disclosureRef
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