RETIREMENT BENEFITS - Post Employment and Defined Contribution Plans (Details) - USD ($)	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Defined Benefit Plan Disclosure
Funded status	$ (38,000,000)	$ (32,000,000)
Amount recognized in accumulated other comprehensive income (loss)	(15,000,000)	(15,000,000)
Service-related expense
Interest cost on benefit obligation	2,000,000	2,000,000	$ 2,000,000
Expected return on plan assets	(1,000,000)	(1,000,000)	0
Amortization of unrecognized
Prior service cost (benefit)	0	(23,000,000)	(31,000,000)
Net actuarial loss	2,000,000	2,000,000	2,000,000
Total service-related benefit	3,000,000	(20,000,000)	(27,000,000)
Non-service-related (benefit) expense	6,000,000	2,000,000	30,000,000
Total net expense	$ 9,000,000	$ (18,000,000)	3,000,000
Defined Benefit Plan, Assumptions Used in Calculations [Abstract]
Discount rate (as a percent)	2.90%	3.95%
Expected return on assets (as a percent)	3.00%	3.00%
Health care cost increase following year (as a percent)	6.75%	7.00%
Ultimate rate to which cost increase is assumed to decline (as a percent)	5.00%	5.00%
Year in which the ultimate rate is reached	2027	2027
Defined Contribution Plans
Maximum percentage contribution by employer of employees eligible pay	6.00%	6.00%
Maximum compensation to be eligible for fixed contribution from employer	$ 100,000
Percentage of fixed contribution by employer, for eligible employees whose compensation is $100,000 or less	2.00%
U.S.
Defined Benefit Plan, Assumptions Used in Calculations [Abstract]
Health care cost increase following year (as a percent)	6.75%	7.00%
Ultimate rate to which cost increase is assumed to decline (as a percent)	5.00%	5.00%
Year in which the ultimate rate is reached	2027	2027
Defined Contribution Plans
Company contributions	$ 404,000,000	$ 396,000,000	383,000,000
Non-U.S.
Defined Benefit Plan, Assumptions Used in Calculations [Abstract]
Health care cost increase following year (as a percent)	6.85%	6.90%
Ultimate rate to which cost increase is assumed to decline (as a percent)	6.85%	6.90%
Year in which the ultimate rate is reached	2020	2019
Defined Contribution Plans
Company contributions	$ 281,000,000	$ 283,000,000	$ 270,000,000