DEBT - Short-Term Borrowings (Details) - USD ($) $ in Millions	Sep. 30, 2023	Dec. 31, 2022
Short-term Debt [Line Items]
Commercial paper	$ 22,843	$ 25,530
Other borrowings	20,323	21,566
Total short-term borrowings	43,166	47,096
Collateralized short-term advances from Federal Home Loan Bank	9,000	12,000
Series A
Short-term Debt [Line Items]
Other borrowings	1,500
Bank
Short-term Debt [Line Items]
Commercial paper	11,124	11,185
Broker-dealer and other
Short-term Debt [Line Items]
Commercial paper	$ 11,719	$ 14,345