Employee Benefits - Components of Plan Benefit Expense (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 27, 2020	Jun. 29, 2019	Jun. 27, 2020	Jun. 29, 2019
Pension | Global Plans
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 9	$ 9	$ 18	$ 18
Interest cost	33	44	68	89
Expected return on plan assets	(85)	(83)	(170)	(168)
Amortization of unrecognized prior service cost (gain)	2	2	4	4
Recognized net (gain) loss	43	10	57	11
Net periodic benefit cost	2	(18)	(23)	(46)
Curtailment (gain) loss	(7)	0	(7)	0
Total plan benefit (income) expense	(5)	(18)	(30)	(46)
Other Nonpension Postretirement | U.S. and Canada
Defined Benefit Plan Disclosure [Line Items]
Service cost	4	4	7	7
Interest cost	8	10	16	20
Expected return on plan assets	(23)	(21)	(46)	(42)
Amortization of unrecognized prior service cost (gain)	(3)	(2)	(5)	(4)
Total plan benefit (income) expense	(14)	(9)	(28)	(19)
Postemployment | Global Plans
Defined Benefit Plan Disclosure [Line Items]
Service cost	1	1	2	2
Interest cost	0	1	0	1
Recognized net (gain) loss	(1)	(1)	(2)	(2)
Total plan benefit (income) expense	$ 0	$ 1	$ 0	$ 1