ACCOUNTING POLICIES - Depreciation (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Property and equipment
Depreciation expense	$ 116	$ 124	$ 116
Buildings | Minimum
Property and equipment
Annual depreciation rates (as a percent)	2.00%
Buildings | Maximum
Property and equipment
Annual depreciation rates (as a percent)	10.00%
Computer Equipment | Minimum
Property and equipment
Annual depreciation rates (as a percent)	17.00%
Computer Equipment | Maximum
Property and equipment
Annual depreciation rates (as a percent)	33.00%
Machinery and equipment | Minimum
Property and equipment
Annual depreciation rates (as a percent)	5.00%
Machinery and equipment | Maximum
Property and equipment
Annual depreciation rates (as a percent)	33.00%