POSTRETIREMENT BENEFIT PLANS - Schedule of Pretax Net Periodic Benefit Cost (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 27, 2020	Sep. 29, 2019	Sep. 27, 2020	Sep. 29, 2019
Qualified defined benefit pension plans
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Service cost	$ 25	$ 129	$ 76	$ 387
Interest cost	385	452	1,154	1,355
Expected return on plan assets	(566)	(575)	(1,698)	(1,725)
Recognized net actuarial losses	213	351	637	1,053
Amortization of prior service credits	(86)	(83)	(257)	(250)
Total net periodic benefit (income) cost	(29)	274	(88)	820
Retiree medical and life insurance plans
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Service cost	3	4	10	11
Interest cost	18	25	53	73
Expected return on plan assets	(32)	(28)	(96)	(83)
Recognized net actuarial losses	(1)	1	(3)	2
Amortization of prior service credits	10	10	29	31
Total net periodic benefit (income) cost	$ (2)	$ 12	$ (7)	$ 34