RETIREMENT BENEFITS - Contributions (Details) - USD ($) $ in Millions	3 Months Ended	6 Months Ended
	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
U.S. | Pension Plans
Defined Benefit Plan, Expected Future Employer Contributions [Abstract]
Company contributions	$ 425	$ 28	$ 463
Company contributions expected to be made during the remainder of the year	18	32	18
U.S. | Postretirement Benefit Plans
Defined Benefit Plan, Expected Future Employer Contributions [Abstract]
Company contributions		0	0
Company contributions expected to be made during the remainder of the year	4	0	4
Non-U.S. plans | Pension Plans
Defined Benefit Plan, Expected Future Employer Contributions [Abstract]
Company contributions		72	64
Company contributions expected to be made during the remainder of the year	86	74	86
Non-U.S. plans | Postretirement Benefit Plans
Defined Benefit Plan, Expected Future Employer Contributions [Abstract]
Company contributions	220	5	223
Company contributions expected to be made during the remainder of the year	$ 2	$ 3	$ 2