Nature of Operations and Significant Accounting Policies (Other Items - Share Repurchases) (Details) (USD $) Share data in Millions, unless otherwise specified	12 Months Ended
Dec. 26, 2014	Dec. 27, 2013	Dec. 28, 2012	Apr. 30, 2013
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Share repurchase program				$ 1,000,000,000
Shares acquired, repurchase amount	$ 517,000,000	$ 353,000,000	$ 734,000,000
Stock repurchased, shares	17	14	34

Number of shares that have been repurchased and retired during the period.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 04

-Article 3

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 505

-SubTopic 10

-Section 50

-Paragraph 2

-URI http://asc.fasb.org/extlink&oid=6928386&loc=d3e21463-112644

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 29, 30

-Article 5

Name:	us-gaap_StockRepurchasedAndRetiredDuringPeriodShares
Namespace Prefix:	us-gaap_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration