Retirement Plans (Details) - USD ($) $ in Millions	3 Months Ended
	Apr. 03, 2021	Apr. 04, 2020
Pension Benefits
Net periodic benefit cost (credit)
Service cost	$ 29	$ 26
Interest cost	63	73
Expected return on plan assets	(144)	(144)
Amortization of net actuarial loss	39	46
Amortization of prior service cost	3	3
Net periodic benefit cost (credit)	(10)	4
Postretirement Benefits Other Than Pensions
Net periodic benefit cost (credit)
Service cost	1	1
Interest cost	1	2
Amortization of net actuarial loss	(1)	0
Amortization of prior service cost	(1)	(1)
Net periodic benefit cost (credit)	$ 0	$ 2