EXIT COSTS AND RESTRUCTURING RESERVES - Reserve Rollforward (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Restructuring Reserve [Roll Forward]
Beginning balance	$ 44	$ 26	$ 30
Additions	31	124	31
Reversals	(5)	(10)	(5)
Utilization	(37)	(96)	(30)
Ending balance	33	44	26
Employee Severance | Salaries & Employee Benefits
Restructuring Reserve [Roll Forward]
Beginning balance	23	2	3
Additions	5	43	6
Reversals	(4)	(1)	(1)
Utilization	(12)	(21)	(6)
Ending balance	12	23	2
Facility Closing | Occupancy & Equipment
Restructuring Reserve [Roll Forward]
Beginning balance	18	24	27
Additions	18	24	22
Reversals	(1)	(5)	(4)
Utilization	(19)	(25)	(21)
Ending balance	16	18	24
Other Restructuring | Other
Restructuring Reserve [Roll Forward]
Beginning balance	3	0	0
Additions	8	57	3
Reversals	0	(4)	0
Utilization	(6)	(50)	(3)
Ending balance	$ 5	$ 3	$ 0