DERIVATIVES ACTIVITIES - Cash Flow Hedges (Details) (USD $)	3 Months Ended
	Mar. 31, 2015	Mar. 31, 2014
Pretax change in accumulated other comprehensive income (loss)
Cash flow hedges expected to be reclassified within 12 months	$ (400,000,000)
Maximum length of time hedged in cash flow hedge	10 years
Cash Flow Hedging
Pretax change in accumulated other comprehensive income (loss)
Effective portion of cash flow hedges included in AOCI	70,000,000	64,000,000
Effective portion of cash flow hedges reclassified from AOCI to earnings	(86,000,000)	(117,000,000)
Interest rate contracts | Cash Flow Hedging
Pretax change in accumulated other comprehensive income (loss)
Effective portion of cash flow hedges included in AOCI	220,000,000	68,000,000
Effective portion of cash flow hedges reclassified from AOCI to earnings	(46,000,000)	(61,000,000)
Foreign exchange contracts | Cash Flow Hedging
Pretax change in accumulated other comprehensive income (loss)
Effective portion of cash flow hedges included in AOCI	(150,000,000)	(6,000,000)
Effective portion of cash flow hedges reclassified from AOCI to earnings	(40,000,000)	(56,000,000)
Credit derivatives | Cash Flow Hedging
Pretax change in accumulated other comprehensive income (loss)
Effective portion of cash flow hedges included in AOCI	$ 0	$ 2,000,000