POSTRETIREMENT BENEFIT PLANS - Schedule of Pretax Net Periodic Benefit Cost (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 26, 2021	Sep. 27, 2020	Sep. 26, 2021	Sep. 27, 2020
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Pension settlement charge			$ 1,665	$ 0
Qualified defined benefit pension plans
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Service cost	$ 26	$ 25	80	76
Interest cost	302	385	923	1,154
Expected return on plan assets	(517)	(566)	(1,655)	(1,698)
Recognized net actuarial losses	210	213	714	637
Amortization of prior service credits	(88)	(86)	(262)	(257)
Pension settlement charge	1,665	0	1,665	0
Non-service FAS retiree medical and life (income)	1,572	(54)	1,385	(164)
Total FAS retiree medical and life (income)	1,598	(29)	1,465	(88)
Retiree medical and life insurance plans
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Service cost	3	3	10	10
Interest cost	13	18	39	53
Expected return on plan assets	(35)	(32)	(105)	(96)
Recognized net actuarial losses	0	(1)	0	(3)
Amortization of prior service credits	9	10	27	29
Non-service FAS retiree medical and life (income)	(13)	(5)	(39)	(17)
Total FAS retiree medical and life (income)	$ (10)	$ (2)	$ (29)	$ (7)