BASIS OF PRESENTATION AND SIGNIFICANT EVENTS - Narrative (Details) $ / shares in Units, $ in Millions		12 Months Ended
Feb. 16, 2017 USD ($)	Dec. 31, 2017 USD ($) employee $ / shares	Sep. 30, 2018 USD ($)
Business Acquisition [Line Items]
Number of associates impacted \| employee		3,600
Percentage of workforce associated impacted		7.80%
Restructuring charges		$ 148
Restructuring charges per diluted share (in dollars per share) \| $ / shares		$ 0.64
Restructuring liability, current		$ 140	$ 29
Break up fee received	$ 1,000
Accounts receivable		$ 854	1,062
Services Accounts Receivable
Business Acquisition [Line Items]
Accounts receivable			$ 148

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Restructuring Charges, Per Diluted Share

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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The number of positions eliminated during the period as a result of restructuring activities.

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The number of positions eliminated during the period as a percentage of total positions eliminated during the period in connection with the restructuring plan(s).

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Amount of expenses associated with exit or disposal activities pursuant to an authorized plan. Excludes expenses related to a discontinued operation or an asset retirement obligation.

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Carrying amount as of the balance sheet date of known and estimated obligations associated with exit from or disposal of business activities or restructurings pursuant to a duly authorized plan, which are expected to be paid in the next twelve months or in the normal operating cycle if longer. Costs of such activities include those for one-time termination benefits, termination of an operating lease or other contract, consolidating or closing facilities, relocating employees, and costs associated with an ongoing benefit arrangement, but excludes costs associated with the retirement of a long-lived asset.

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