RETIREMENT BENEFITS - Contributions (Details) - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016
U.S. | Pension Plans
Defined Benefit Plan, Expected Future Employer Contributions [Abstract]
Company contributions for the nine months ended September 30	$ 90	$ 541
Company contributions made or expected to be made during the remainder of the year	16	15
U.S. | Postretirement Benefit Plans
Defined Benefit Plan, Expected Future Employer Contributions [Abstract]
Company contributions for the nine months ended September 30	30	6
Company contributions made or expected to be made during the remainder of the year	0	0
Non-U.S. plans | Pension Plans
Defined Benefit Plan, Expected Future Employer Contributions [Abstract]
Company contributions for the nine months ended September 30	103	58
Company contributions made or expected to be made during the remainder of the year	35	68
Non-U.S. plans | Postretirement Benefit Plans
Defined Benefit Plan, Expected Future Employer Contributions [Abstract]
Company contributions for the nine months ended September 30	7	4
Company contributions made or expected to be made during the remainder of the year	$ 2	$ 5