LOANS (Details 8) (USD $) In Millions, unless otherwise specified	3 Months Ended		3 Months Ended	12 Months Ended	3 Months Ended	12 Months Ended	3 Months Ended	12 Months Ended	3 Months Ended	12 Months Ended	3 Months Ended	12 Months Ended	3 Months Ended	12 Months Ended
	Mar. 31, 2011	Sep. 30, 2011	Mar. 31, 2012 Corporate	Dec. 31, 2011 Corporate	Mar. 31, 2012 Corporate Commercial and industrial	Dec. 31, 2011 Corporate Commercial and industrial	Mar. 31, 2012 Corporate Loans to financial institutions	Dec. 31, 2011 Corporate Loans to financial institutions	Mar. 31, 2012 Corporate Mortgage and real estate	Dec. 31, 2011 Corporate Mortgage and real estate	Mar. 31, 2012 Corporate Lease financing	Dec. 31, 2011 Corporate Lease financing	Mar. 31, 2012 Corporate Other	Dec. 31, 2011 Corporate Other
Financing receivable impaired
Recorded investment		$ 1,170	$ 2,973	$ 3,236	$ 1,228	$ 1,144	$ 615	$ 779	$ 942	$ 1,029	$ 11	$ 13	$ 177	$ 271
Unpaid principal balance			4,078	4,488	1,571	1,538	807	1,213	1,312	1,240	19	21	369	476
Related specific allowance		467	419	420	182	186	25	20	158	151			54	63
Average Carrying Value			3,804	4,434	1,267	1,448	940	1,060	1,264	1,485	17	25	316	416
Interest Income Recognized	13		26	109	7	76			18	14			1	17
Impaired financing receivable with specific allowance			1,228	1,239	500	501	56	68	548	540			124	130
Impaired financing receivable without specific allowance			$ 1,745	$ 1,997	$ 728	$ 643	$ 559	$ 711	$ 394	$ 489	$ 11	$ 13	$ 53	$ 141