FAIR VALUE MEASUREMENTS (Details 8) (Maiden Lane III, USD $)	1 Months Ended
	Apr. 30, 2012	Mar. 31, 2012
VARIABLE INTEREST ENTITY
Fair Value Change		$ 450,000,000
ML III assets sold by FRBNY	7,500,000,000
200 basis point increase
VARIABLE INTEREST ENTITY
Fair Value Change		(717,000,000)
200 basis point decrease
VARIABLE INTEREST ENTITY
Fair Value Change		824,000,000
400 basis point increase
VARIABLE INTEREST ENTITY
Fair Value Change		(1,346,000,000)
400 basis point decrease
VARIABLE INTEREST ENTITY
Fair Value Change		1,777,000,000
10% increase
VARIABLE INTEREST ENTITY
Fair Value Change		711,000,000
10% decrease
VARIABLE INTEREST ENTITY
Fair Value Change		(720,000,000)
20% increase
VARIABLE INTEREST ENTITY
Fair Value Change		1,415,000,000
20% decrease
VARIABLE INTEREST ENTITY
Fair Value Change		$ (1,451,000,000)