Postretirement Benefit Plans - Components of Net Periodic Benefit Costs (Details) - USD ($) $ in Millions	3 Months Ended
	Apr. 03, 2020	Mar. 29, 2019
Pension
Net periodic benefit income
Service cost	$ 16	$ 9
Interest cost	69	52
Expected return on plan assets	(158)	(95)
Amortization of net actuarial loss	2	0
Amortization of prior service credit	(7)
Contractual termination benefits	1
Net periodic benefit income	(77)	(34)
Other Benefits
Net periodic benefit income
Service cost	0	1
Interest cost	2	2
Expected return on plan assets	(5)	(4)
Amortization of net actuarial loss	0	(2)
Amortization of prior service credit	0
Contractual termination benefits	0
Net periodic benefit income	$ (3)	$ (3)