FAIR VALUE MEASUREMENT - Items Measured at Fair Value on a Nonrecurring Basis (Details) - USD ($) $ in Millions	Sep. 30, 2024	Dec. 31, 2023
Items Measured at Fair Value on a Nonrecurring Basis
Non-marketable equity securities measured using the measurement alternative	$ 7,953	$ 7,902
Nonrecurring | Level 2
Items Measured at Fair Value on a Nonrecurring Basis
Loans HFS	352	495
Other real estate owned	0	0
Loans	0	0
Non-marketable equity securities measured using the measurement alternative	0	0
Total assets	352	495
Nonrecurring | Level 3
Items Measured at Fair Value on a Nonrecurring Basis
Loans HFS	244	676
Other real estate owned	9	4
Loans	212	328
Non-marketable equity securities measured using the measurement alternative	102	359
Total assets	567	1,367
Fair value | Nonrecurring
Items Measured at Fair Value on a Nonrecurring Basis
Loans HFS	596	1,171
Other real estate owned	9	4
Loans	212	328
Non-marketable equity securities measured using the measurement alternative	102	359
Total assets	$ 919	$ 1,862