Pensions and Other Benefit Plans - Components of Net Periodic Benefit Cost (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 29, 2019	Dec. 30, 2018	Dec. 31, 2017
Retirement Plans
Components of net periodic benefit cost
Service cost	$ 1,163	$ 1,283	$ 1,080
Interest cost	1,096	996	927
Expected return on plan assets	(2,322)	(2,212)	(2,041)
Amortization of prior service cost (credit)	4	3	2
Recognized actuarial losses	579	852	609
Curtailments and settlements	73	1	17
Net periodic benefit cost	593	923	594
Other Benefit Plans
Components of net periodic benefit cost
Service cost	274	269	247
Interest cost	185	148	159
Expected return on plan assets	(6)	(7)	(6)
Amortization of prior service cost (credit)	(31)	(31)	(30)
Recognized actuarial losses	129	123	138
Curtailments and settlements	0	0	0
Net periodic benefit cost	$ 551	$ 502	$ 508