GUARANTEES, LEASES AND COMMITMENTS - Performance Risk (Details) - USD ($) $ in Billions	Jun. 30, 2022	Dec. 31, 2021
Guarantor Obligations
Maximum potential amount of future payments	$ 419.7	$ 427.0
Investment grade
Guarantor Obligations
Maximum potential amount of future payments	90.3	91.9
Non-investment grade
Guarantor Obligations
Maximum potential amount of future payments	25.3	25.8
Not rated
Guarantor Obligations
Maximum potential amount of future payments	304.1	309.3
Financial standby letters of credit
Guarantor Obligations
Maximum potential amount of future payments	92.8	92.7
Financial standby letters of credit | Investment grade
Guarantor Obligations
Maximum potential amount of future payments	80.2	81.4
Financial standby letters of credit | Non-investment grade
Guarantor Obligations
Maximum potential amount of future payments	10.8	11.3
Financial standby letters of credit | Not rated
Guarantor Obligations
Maximum potential amount of future payments	1.8	0.0
Performance guarantees
Guarantor Obligations
Maximum potential amount of future payments	11.9	13.0
Performance guarantees | Investment grade
Guarantor Obligations
Maximum potential amount of future payments	9.7	10.5
Performance guarantees | Non-investment grade
Guarantor Obligations
Maximum potential amount of future payments	2.2	2.5
Performance guarantees | Not rated
Guarantor Obligations
Maximum potential amount of future payments	0.0	0.0
Derivative instruments deemed to be guarantees
Guarantor Obligations
Maximum potential amount of future payments	53.9	63.5
Derivative instruments deemed to be guarantees | Investment grade
Guarantor Obligations
Maximum potential amount of future payments	0.0	0.0
Derivative instruments deemed to be guarantees | Non-investment grade
Guarantor Obligations
Maximum potential amount of future payments	0.0	0.0
Derivative instruments deemed to be guarantees | Not rated
Guarantor Obligations
Maximum potential amount of future payments	53.9	63.5
Loans sold with recourse
Guarantor Obligations
Maximum potential amount of future payments	1.6	1.7
Loans sold with recourse | Investment grade
Guarantor Obligations
Maximum potential amount of future payments	0.0	0.0
Loans sold with recourse | Non-investment grade
Guarantor Obligations
Maximum potential amount of future payments	0.0	0.0
Loans sold with recourse | Not rated
Guarantor Obligations
Maximum potential amount of future payments	1.6	1.7
Securities lending indemnifications
Guarantor Obligations
Maximum potential amount of future payments	120.5	121.9
Securities lending indemnifications | Investment grade
Guarantor Obligations
Maximum potential amount of future payments	0.0	0.0
Securities lending indemnifications | Non-investment grade
Guarantor Obligations
Maximum potential amount of future payments	0.0	0.0
Securities lending indemnifications | Not rated
Guarantor Obligations
Maximum potential amount of future payments	120.5	121.9
Credit card merchant processing
Guarantor Obligations
Maximum potential amount of future payments	125.6	119.4
Credit card merchant processing | Investment grade
Guarantor Obligations
Maximum potential amount of future payments	0.0	0.0
Credit card merchant processing | Non-investment grade
Guarantor Obligations
Maximum potential amount of future payments	0.0	0.0
Credit card merchant processing | Not rated
Guarantor Obligations
Maximum potential amount of future payments	125.6	119.4
Credit card arrangements with partners
Guarantor Obligations
Maximum potential amount of future payments	0.7	0.8
Credit card arrangements with partners | Investment grade
Guarantor Obligations
Maximum potential amount of future payments	0.0	0.0
Credit card arrangements with partners | Non-investment grade
Guarantor Obligations
Maximum potential amount of future payments	0.0	0.0
Credit card arrangements with partners | Not rated
Guarantor Obligations
Maximum potential amount of future payments	0.7	0.8
Other
Guarantor Obligations
Maximum potential amount of future payments	12.7	14.0
Other | Investment grade
Guarantor Obligations
Maximum potential amount of future payments	0.4	0.0
Other | Non-investment grade
Guarantor Obligations
Maximum potential amount of future payments	12.3	12.0
Other | Not rated
Guarantor Obligations
Maximum potential amount of future payments	$ 0.0	$ 2.0