Employee Benefits (Components of Company Plan Benefit Expense) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 29, 2013	Jun. 30, 2012	Jun. 29, 2013	Jun. 30, 2012
Pension [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 34	$ 26	$ 68	$ 54
Interest cost	50	52	100	103
Expected return on plan assets	(89)	(85)	(179)	(171)
Amortization of unrecognized prior service cost	4	3	8	7
Total expense	(1)	(4)	(3)	(7)
Other Nonpension Postretirement [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	8	7	17	13
Interest cost	12	13	24	26
Expected return on plan assets	(22)	(21)	(44)	(42)
Amortization of unrecognized prior service cost	(1)	0	(2)	0
Total expense	(3)	(1)	(5)	(3)
Postemployment [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	1	2	3	4
Interest cost	1	1	2	2
Recognized net loss	1	1	3	2
Total expense	$ 3	$ 4	$ 8	$ 8