MORTGAGE BANKING AND OTHER SERVICED LOANS - Changes Related to MSRs - Amortization Method (Details) - USD ($) $ in Millions	Dec. 31, 2022	Dec. 31, 2021
Education
Servicing Asset at Amortized Cost [Line Items]
Other serviced loans	$ 602	$ 761
Commercial and Industrial
Servicing Asset at Amortized Cost [Line Items]
Other serviced loans	$ 91	$ 80

Aggregate amount of servicing assets that are subsequently measured at fair value and servicing assets that are subsequently measured using the amortization method.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 860
-SubTopic 50
-Section 45
-Paragraph 2
-Subparagraph (b)
-URI https://asc.fasb.org/extlink&oid=6469459&loc=d3e122501-111745

Name:	us-gaap_ServicingAsset
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant