LOANS - Corporate Troubled Debt Restructurings (Details) - Corporate - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Financing receivable impaired
Carrying Value	$ 77	$ 8	$ 78	$ 52
TDRs involving changes in the amount and/or timing of principal payments	35	7	36	34
TDRs involving changes in the amount and/or timing of interest payments	0	1	0	18
TDRs involving changes in the amount and/or timing of both principal and interest payments	43	0	$ 43	0
Period within which default occurred post-modification			1 year
Number of days past due, default status			60 days
Carrying Value	558	673	$ 558	673
TDR in payment default	1		$ 1	0
Commercial market loans
Financing receivable impaired
Number of days past due, default status			90 days
Commercial and industrial
Financing receivable impaired
Carrying Value	66	7	$ 66	47
TDRs involving changes in the amount and/or timing of principal payments	34	7	34	30
TDRs involving changes in the amount and/or timing of interest payments	0	0	0	17
TDRs involving changes in the amount and/or timing of both principal and interest payments	33	0	33	0
Carrying Value	118	203	118	203
TDR in payment default	0		0	0
Financial institutions
Financing receivable impaired
Carrying Value	0	0	0	0
TDRs involving changes in the amount and/or timing of principal payments	0	0	0	0
TDRs involving changes in the amount and/or timing of interest payments	0	0	0	0
TDRs involving changes in the amount and/or timing of both principal and interest payments	0	0	0	0
Carrying Value	1	0	1	0
TDR in payment default	1		1	0
Mortgage and real estate
Financing receivable impaired
Carrying Value	11	1	12	5
TDRs involving changes in the amount and/or timing of principal payments	1	0	2	4
TDRs involving changes in the amount and/or timing of interest payments	0	1	0	1
TDRs involving changes in the amount and/or timing of both principal and interest payments	10	0	10	0
Carrying Value	113	130	113	130
TDR in payment default	0		0	0
Other
Financing receivable impaired
Carrying Value	0	0	0	0
TDRs involving changes in the amount and/or timing of principal payments	0	0	0	0
TDRs involving changes in the amount and/or timing of interest payments	0	0	0	0
TDRs involving changes in the amount and/or timing of both principal and interest payments	0	0	0	0
Carrying Value	326	$ 340	326	340
TDR in payment default	$ 0		$ 0	$ 0