FAIR VALUE MEASUREMENT - Items Measured at Fair Value on a Nonrecurring Basis (Details) - USD ($) $ in Millions	Sep. 30, 2025	Dec. 31, 2024
Items Measured at Fair Value on a Nonrecurring Basis
Non-marketable equity securities measured using the measurement alternative	$ 7,413	$ 7,399
Nonrecurring | Level 2
Items Measured at Fair Value on a Nonrecurring Basis
Loans HFS	331	413
Other real estate owned	0	0
Loans	0	0
Non-marketable equity securities measured using the measurement alternative	0	0
Total assets	331	413
Nonrecurring | Level 3
Items Measured at Fair Value on a Nonrecurring Basis
Loans HFS	236	271
Other real estate owned	2	1
Loans	620	353
Non-marketable equity securities measured using the measurement alternative	291	184
Total assets	1,149	809
Fair value | Nonrecurring
Items Measured at Fair Value on a Nonrecurring Basis
Loans HFS	567	684
Other real estate owned	2	1
Loans	620	353
Non-marketable equity securities measured using the measurement alternative	291	184
Total assets	$ 1,480	$ 1,222