BORROWED FUNDS - Short Term Debt (Details) (USD $) In Millions, unless otherwise specified	Sep. 30, 2014	Dec. 31, 2013
Short-term Debt [Line Items]
Total short-term borrowed funds	$ 11,899	$ 7,042
Federal funds purchased
Short-term Debt [Line Items]
Total short-term borrowed funds	0	689
Securities sold under agreements to repurchase
Short-term Debt [Line Items]
Total short-term borrowed funds	5,184	4,102
Other short-term borrowed funds
Short-term Debt [Line Items]
Total short-term borrowed funds	$ 6,715	$ 2,251