PENSION AND OTHER POSTRETIREMENT BENEFIT PLANS - Changes in Fair Value of Plan Assets (Details) - USD ($)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Defined Benefit Plan Disclosure [Line Items]
Actual return on plan assets	$ 1.00	$ 1.00	$ 1.00
Pension
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets at beginning of year (estimated)	5,351,000,000	5,491,000,000
Adjustment for final fair value of plan assets	18,000,000	7,000,000
Actual return on plan assets	553,000,000	27,000,000
Foreign currency translation	59,000,000	29,000,000
Employer contributions and benefit payments	57,000,000	78,000,000
Plan participants’ contributions	0	0
Plan transfers	3,000,000	1,000,000
Plan acquisitions	0	137,000,000
Benefits paid (includes lump sum settlements)	(527,000,000)	(419,000,000)
Fair value of plan assets at end of year (estimated)	5,514,000,000	5,351,000,000	5,491,000,000
Other Postretirement Benefits
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets at beginning of year (estimated)	0	0
Adjustment for final fair value of plan assets	0	0
Actual return on plan assets	0	0
Foreign currency translation	0	0
Employer contributions and benefit payments	20,000,000	21,000,000
Plan participants’ contributions	6,000,000	7,000,000
Plan transfers	0	0
Plan acquisitions	0	0
Benefits paid (includes lump sum settlements)	(26,000,000)	(28,000,000)
Fair value of plan assets at end of year (estimated)	$ 0	$ 0	$ 0