FAIR VALUE MEASUREMENT - Items Measured at Fair Value on a Nonrecurring Basis (Details) - USD ($) $ in Millions	Sep. 30, 2023	Dec. 31, 2022
Items Measured at Fair Value on a Nonrecurring Basis
Non-marketable equity securities measured using the measurement alternative	$ 7,759	$ 8,040
Nonrecurring | Level 2
Items Measured at Fair Value on a Nonrecurring Basis
Loans HFS	354	457
Other real estate owned	0	0
Loans	0	0
Non-marketable equity securities measured using the measurement alternative	0	0
Total assets	354	457
Nonrecurring | Level 3
Items Measured at Fair Value on a Nonrecurring Basis
Loans HFS	1,193	1,879
Other real estate owned	2	1
Loans	407	69
Non-marketable equity securities measured using the measurement alternative	60	597
Total assets	1,662	2,546
Fair value | Nonrecurring
Items Measured at Fair Value on a Nonrecurring Basis
Loans HFS	1,547	2,336
Other real estate owned	2	1
Loans	407	69
Non-marketable equity securities measured using the measurement alternative	60	597
Total assets	$ 2,016	$ 3,003