Retirement Plans - Net periodic benefit cost and other changes in plan assets and benefit obligations recognized in OCI (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Jan. 02, 2016	Jan. 03, 2015
Other changes in plan assets and benefit obligations recognized in OCI
Current year actuarial loss (gain)	$ 382	$ (136)	$ 734
Amortization of net actuarial loss	(104)	(150)	(114)
Amortization of prior service credit (cost)	7	7	8
Pension Benefits
Net periodic benefit cost (credit)
Service cost	98	113	109
Interest cost	338	327	334
Expected return on plan assets	(490)	(483)	(462)
Amortization of prior service cost (credit)	15	16	15
Amortization of net actuarial loss	104	148	112
Curtailment and other charges		6
Net periodic benefit cost (credit)	65	127	108
Other changes in plan assets and benefit obligations recognized in OCI
Current year actuarial loss (gain)	399	(107)	729
Current year prior service cost (credit)			12
Amortization of net actuarial loss	(104)	(148)	(112)
Amortization of prior service credit (cost)	(15)	(18)	(15)
Total recognized in OCI, before taxes	280	(273)	614
Total recognized in net periodic benefit cost and OCI	345	(146)	722
Postretirement Benefits Other Than Pensions
Net periodic benefit cost (credit)
Service cost	3	4	4
Interest cost	16	15	19
Amortization of prior service cost (credit)	(22)	(25)	(23)
Amortization of net actuarial loss		2	2
Net periodic benefit cost (credit)	(3)	(4)	2
Other changes in plan assets and benefit obligations recognized in OCI
Current year actuarial loss (gain)	(17)	(29)	5
Current year prior service cost (credit)	(12)		(30)
Amortization of net actuarial loss		(2)	(2)
Amortization of prior service credit (cost)	22	25	23
Total recognized in OCI, before taxes	(7)	(6)	(4)
Total recognized in net periodic benefit cost and OCI	$ (10)	$ (10)	$ (2)