Retirement Plans - Change in the projected benefit obligation and in the fair value of plan assets (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Jan. 02, 2016	Jan. 03, 2015
Pension Benefits
Change in benefit obligation
Benefit obligation at beginning of year	$ 7,476	$ 8,006
Service cost	98	113	$ 109
Interest cost	338	327	334
Actuarial losses (gains)	571	(470)
Benefits paid	(410)	(423)
Curtailments and special termination benefits	(7)	(4)
Foreign exchange rate changes and other	(75)	(73)
Benefit obligation at end of year	7,991	7,476	8,006
Change in fair value of plan assets
Balance at beginning of year	6,668	6,979
Actual return on plan assets	655	113
Employer contributions	40	55
Benefits paid	(410)	(423)
Foreign exchange rate changes and other	(79)	(56)
Balance at end of year	6,874	6,668	6,979
Funded status at end of year	(1,117)	(808)
Postretirement Benefits Other Than Pensions
Change in benefit obligation
Benefit obligation at beginning of year	364	413
Service cost	3	4	4
Interest cost	16	15	19
Plan participants' contributions	5	5
Actuarial losses (gains)	(17)	(29)
Benefits paid	(42)	(44)
Plan amendment	(12)
Benefit obligation at end of year	317	364	$ 413
Change in fair value of plan assets
Funded status at end of year	$ (317)	$ (364)