RETIREMENT AND OTHER BENEFIT PROGRAMS - Changes in Fair Value Measurements that Used Significant Unobservable Inputs (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Significant unobservable inputs (Level 3)
Defined Benefit Plan, Change in Fair Value of Plan Assets, Level 3 Reconciliation [Roll Forward]
Beginning of period	$ 10	$ 18
Transfers out		(8)
Purchases	0
End of period	10	10
Common/Collective Trust Funds
Defined Benefit Plan, Change in Fair Value of Plan Assets, Level 3 Reconciliation [Roll Forward]
Beginning of period	919
End of period	668	919
Common/Collective Trust Funds | Significant unobservable inputs (Level 3)
Defined Benefit Plan, Change in Fair Value of Plan Assets, Level 3 Reconciliation [Roll Forward]
Beginning of period	0	8
Transfers out		(8)
Purchases	0
End of period	0	0
Other Holdings
Defined Benefit Plan, Change in Fair Value of Plan Assets, Level 3 Reconciliation [Roll Forward]
Beginning of period	172
End of period	76	172
Other Holdings | Significant unobservable inputs (Level 3)
Defined Benefit Plan, Change in Fair Value of Plan Assets, Level 3 Reconciliation [Roll Forward]
Beginning of period	10	10
Transfers out		0
Purchases	0
End of period	$ 10	$ 10