Employee Benefits - Components of Plan Benefit Expense (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Oct. 01, 2016	Oct. 03, 2015	Oct. 01, 2016	Oct. 03, 2015
Defined Benefit Plan Disclosure [Line Items]
Pension remeasurement expense	$ 28
Pension
Defined Benefit Plan Disclosure [Line Items]
Service cost	25	$ 28	$ 74	$ 84
Interest cost	43	50	131	156
Expected return on plan assets	(87)	(100)	(266)	(300)
Amortization of unrecognized prior service cost (credit)	3	4	10	10
Recognized net loss	28	0	28	0
Total plan benefit (income) expense	12	(18)	(23)	(50)
Other Nonpension Postretirement
Defined Benefit Plan Disclosure [Line Items]
Service cost	5	7	15	24
Interest cost	10	11	29	36
Expected return on plan assets	(22)	(25)	(67)	(75)
Amortization of unrecognized prior service cost (credit)	(2)	(2)	(7)	(3)
Total plan benefit (income) expense	(9)	(9)	(30)	(18)
Postemployment
Defined Benefit Plan Disclosure [Line Items]
Service cost	1	2	5	5
Interest cost	1	1	3	3
Recognized net loss	1	1	3	3
Total plan benefit (income) expense	$ 3	$ 4	$ 11	$ 11