DEBT - Short-Term Borrowings (Details) - USD ($) $ in Millions	Mar. 31, 2023	Dec. 31, 2022
Short-term Debt [Line Items]
Commercial paper	$ 21,627	$ 25,530
Other borrowings	18,560	21,566
Total short-term borrowings	40,187	47,096
Collateralized short-term advances from Federal Home Loan Bank	6,800	12,000
Bank
Short-term Debt [Line Items]
Commercial paper	11,036	11,185
Broker-dealer and other
Short-term Debt [Line Items]
Commercial paper	$ 10,591	$ 14,345