Employee Benefits (Contributions to Employee Benefit Plans) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 27, 2014	Sep. 28, 2013	Sep. 27, 2014	Sep. 28, 2013	Dec. 28, 2013
Defined Benefit Plan Disclosure [Line Items]
Employer contributions to employee benefit plans	$ 7	$ 6	$ 44	$ 42	$ 48
Total current year projected employer contributions			57
Pension [Member]
Defined Benefit Plan Disclosure [Line Items]
Employer contributions to employee benefit plans	5	2	34	30	34
Total current year projected employer contributions			43
Nonpension Postretirement [Member]
Defined Benefit Plan Disclosure [Line Items]
Employer contributions to employee benefit plans	2	4	10	12	14
Total current year projected employer contributions			$ 14