GUARANTEES AND COMMITMENTS - Performance Risk (Details) - USD ($) $ in Billions	Mar. 31, 2026	Dec. 31, 2025
Guarantor Obligations
Maximum potential amount of future payments	$ 666.9	$ 649.7
Classified based on internal and external credit ratings
Guarantor Obligations
Maximum potential amount of future payments	89.6	92.3
Investment grade
Guarantor Obligations
Maximum potential amount of future payments	68.1	70.0
Non-investment grade
Guarantor Obligations
Maximum potential amount of future payments	20.6	21.4
Not rated
Guarantor Obligations
Maximum potential amount of future payments	0.9	0.9
Financial standby letters of credit
Guarantor Obligations
Maximum potential amount of future payments	80.5	83.2
Financial standby letters of credit \| Classified based on internal and external credit ratings
Guarantor Obligations
Maximum potential amount of future payments	80.5	83.2
Financial standby letters of credit \| Investment grade
Guarantor Obligations
Maximum potential amount of future payments	68.1	70.0
Financial standby letters of credit \| Non-investment grade
Guarantor Obligations
Maximum potential amount of future payments	12.4	13.2
Financial standby letters of credit \| Not rated
Guarantor Obligations
Maximum potential amount of future payments	0.0	0.0
Loans sold with recourse
Guarantor Obligations
Maximum potential amount of future payments	0.9	0.9
Loans sold with recourse \| Classified based on internal and external credit ratings
Guarantor Obligations
Maximum potential amount of future payments	0.9	0.9
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	0.9	0.9
Other
Guarantor Obligations
Maximum potential amount of future payments	8.2	8.2
Other \| Classified based on internal and external credit ratings
Guarantor Obligations
Maximum potential amount of future payments	8.2	8.2
Other \| Investment grade
Guarantor Obligations
Maximum potential amount of future payments	0.0	0.0
Other \| Non-investment grade
Guarantor Obligations
Maximum potential amount of future payments	8.2	8.2
Other \| Not rated
Guarantor Obligations
Maximum potential amount of future payments	$ 0.0	$ 0.0