POSTRETIREMENT BENEFIT PLANS - Narrative (Details) - USD ($)	3 Months Ended		6 Months Ended
	Jun. 28, 2020	Jun. 30, 2019	Jun. 28, 2020	Jun. 30, 2019
Defined Benefit Plan Disclosure [Line Items]
Recognition of previously deferred postretirement benefit plan amounts, before tax	$ 140,000,000	$ 288,000,000	$ 280,000,000	$ 577,000,000
Recognition of previously deferred postretirement benefit plan amounts, net of tax	110,000,000	227,000,000	220,000,000	454,000,000
Retiree medical and life insurance plans
Defined Benefit Plan Disclosure [Line Items]
Recognition of previously deferred postretirement benefit plan amounts, before tax	5,000,000	9,000,000	10,000,000	20,000,000
Qualified defined benefit pension plans
Defined Benefit Plan Disclosure [Line Items]
Material contributions to qualified defined benefit pension plans	$ 0	$ 0	$ 0	$ 0