Employee Benefits (Components of Company Plan Benefit Expense) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 28, 2014	Jun. 29, 2013	Jun. 28, 2014	Jun. 29, 2013
Pension [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 27	$ 34	$ 53	$ 68
Interest cost	56	50	113	100
Expected return on plan assets	(105)	(89)	(209)	(179)
Amortization of unrecognized prior service cost	4	4	7	8
Total expense	(18)	(1)	(36)	(3)
Other Nonpension Postretirement [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	7	8	14	17
Interest cost	13	12	27	24
Expected return on plan assets	(25)	(22)	(49)	(44)
Amortization of unrecognized prior service cost	0	(1)	(1)	(2)
Total expense	(5)	(3)	(9)	(5)
Postemployment [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	2	1	4	3
Interest cost	1	1	2	2
Recognized net loss	1	1	2	3
Total expense	$ 4	$ 3	$ 8	$ 8