FAIR VALUE MEASUREMENT - Items Measured at Fair Value on a Nonrecurring Basis (Details) - USD ($) $ in Millions	Jun. 30, 2024	Dec. 31, 2023
Items Measured at Fair Value on a Nonrecurring Basis
Non-marketable equity securities measured using the measurement alternative	$ 7,789	$ 7,902
Nonrecurring | Level 2
Items Measured at Fair Value on a Nonrecurring Basis
Loans HFS	1,223	495
Other real estate owned	0	0
Loans	0	0
Non-marketable equity securities measured using the measurement alternative	0	0
Total assets	1,223	495
Nonrecurring | Level 3
Items Measured at Fair Value on a Nonrecurring Basis
Loans HFS	332	676
Other real estate owned	1	4
Loans	176	328
Non-marketable equity securities measured using the measurement alternative	31	359
Total assets	540	1,367
Fair value | Nonrecurring
Items Measured at Fair Value on a Nonrecurring Basis
Loans HFS	1,555	1,171
Other real estate owned	1	4
Loans	176	328
Non-marketable equity securities measured using the measurement alternative	31	359
Total assets	$ 1,763	$ 1,862