POSTRETIREMENT BENEFIT PLANS - Narrative (Details) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 29, 2019	Sep. 30, 2018	Sep. 29, 2019	Sep. 30, 2018
Defined Benefit Plan Disclosure [Line Items]
Recognition of previously deferred postretirement benefit plan amounts, before tax	$ 290,000,000	$ 382,000,000	$ 867,000,000	$ 1,100,000,000
Recognition of previously deferred postretirement benefit plan amounts, net of tax	227,000,000	300,000,000	681,000,000	900,000,000
Retiree medical and life insurance plans
Defined Benefit Plan Disclosure [Line Items]
Recognition of previously deferred postretirement benefit plan amounts, before tax	11,000,000	13,000,000	31,000,000	42,000,000
Qualified defined benefit pension plans
Defined Benefit Plan Disclosure [Line Items]
Material contributions to qualified defined benefit pension plans	$ 0	$ 1,500,000,000	$ 0	$ 5,000,000,000.0