Shareholders' Equity (Details) (USD $) In Millions, except Share data in Thousands, unless otherwise specified	12 Months Ended
	Dec. 27, 2014	Dec. 28, 2013		Dec. 29, 2012
Repurchase Of Shares Of The Company's Common Stock By Authorization Date
Shares Repurchased (in shares)	11,225	10,922	[1]	14,891
Stock Repurchased During Period, Value	$ 820	$ 750	[1]	$ 985
Stock Repurchase Program, Remaining Authorized Repurchase Amount	1,100
Value of share repurchases in current fiscal year but with settlement dates in subsequent year		20
Value of share repurchases in current fiscal year but with settlement dates in subsequent year (in shares)		300
November 2014 [Member]
Repurchase Of Shares Of The Company's Common Stock By Authorization Date
Shares Repurchased (in shares)	0	0		0
Stock Repurchased During Period, Value	0	0		0
Authorized Share Repurchases	1,000
Expiration Date Of Share Repurchase Authorization	May 2016
November 2012
Repurchase Of Shares Of The Company's Common Stock By Authorization Date
Shares Repurchased (in shares)	2,737	10,922		1,069
Stock Repurchased During Period, Value	203	750		47
November 2013
Repurchase Of Shares Of The Company's Common Stock By Authorization Date
Shares Repurchased (in shares)	8,488	0		0
Stock Repurchased During Period, Value	617	0		0
Authorized Share Repurchases		750
Expiration Date Of Share Repurchase Authorization		May 2015
November 2011
Repurchase Of Shares Of The Company's Common Stock By Authorization Date
Shares Repurchased (in shares)	0	0		11,035
Stock Repurchased During Period, Value	0	0		750
January 2011
Repurchase Of Shares Of The Company's Common Stock By Authorization Date
Shares Repurchased (in shares)	0	0		2,787
Stock Repurchased During Period, Value	$ 0	$ 0		$ 188

[1] 2013 amount excludes and 2012 amount includes the effect of $20 million in share repurchases (0.3 million shares) with trade dates prior to the 2012 fiscal year end but with settlement dates subsequent to the 2012 fiscal year end.