EXIT COSTS AND RESTRUCTURING RESERVES - Reserve Rollforward (Details) - USD ($) $ in Millions	9 Months Ended	12 Months Ended
	Sep. 30, 2015	Dec. 31, 2014
Restructuring Reserve [Roll Forward]
Beginning balance	$ 44	$ 26
Additions	29	124
Reversals	(3)	(10)
Utilization	(32)	(96)
Ending balance	38	44
Employee Severance | Salaries & Employee Benefits
Restructuring Reserve [Roll Forward]
Beginning balance	23	2
Additions	5	43
Reversals	(2)	(1)
Utilization	(10)	(21)
Ending balance	16	23
Facility Closing | Occupancy & Equipment
Restructuring Reserve [Roll Forward]
Beginning balance	18	24
Additions	18	24
Reversals	(1)	(5)
Utilization	(16)	(25)
Ending balance	19	18
Other Restructuring | Other
Restructuring Reserve [Roll Forward]
Beginning balance	3	0
Additions	6	57
Reversals	0	(4)
Utilization	(6)	(50)
Ending balance	$ 3	$ 3