SIGNIFICANT ACCOUNTING POLICIES - Factored Receivables (Details) - USD ($) $ in Billions	3 Months Ended	12 Months Ended
Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2017	Dec. 31, 2016
SIGNIFICANT ACCOUNTING POLICIES
Gross proceeds from factored receivables	$ 0.7	$ 0.4	$ 1.9	$ 1.2
Net gains and losses associated with the transfer of receivables

Reflects the net positive or negative amount derived from subtracting from net proceeds of sale, the carrying amounts, net of allocated reserves, of accounts receivable transferred to a third party in a transaction that qualifies for sales treatment.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 860
-SubTopic 20
-Section 50
-Paragraph 5
-URI http://asc.fasb.org/extlink&oid=82924980&loc=d3e107425-111719

Name:	us-gaap_GainLossOnSaleOfAccountsReceivable
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration