Employee Benefits - Components of Plan Benefit Expense (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 26, 2020	Sep. 28, 2019	Sep. 26, 2020	Sep. 28, 2019
Pension | Global Plans
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 9	$ 9	$ 27	$ 27
Interest cost	31	42	99	131
Expected return on plan assets	(87)	(86)	(257)	(254)
Amortization of unrecognized prior service cost (gain)	1	1	5	5
Recognized net (gain) loss	7	23	64	34
Net periodic benefit cost	(39)	(11)	(62)	(57)
Curtailment (gain) loss	0	(11)	(7)	(11)
Total plan benefit (income) expense	(39)	(22)	(69)	(68)
Other Nonpension Postretirement | U.S. and Canada
Defined Benefit Plan Disclosure [Line Items]
Service cost	2	5	9	12
Interest cost	7	10	23	30
Expected return on plan assets	(24)	(23)	(70)	(65)
Amortization of unrecognized prior service cost (gain)	(1)	(2)	(6)	(6)
Recognized net (gain) loss	0	(55)	0	(55)
Net periodic benefit cost	(16)	(65)	(44)	(84)
Curtailment (gain) loss	0	(6)	0	(6)
Total plan benefit (income) expense	(16)	(71)	(44)	(90)
Postemployment | Global Plans
Defined Benefit Plan Disclosure [Line Items]
Service cost	1	1	3	3
Interest cost	1	0	1	1
Recognized net (gain) loss	0	(1)	(2)	(3)
Total plan benefit (income) expense	$ 2	$ 0	$ 2	$ 1