Nature of Operations and Significant Accounting Policies - Share Repurchases (Details) - USD ($) shares in Millions	3 Months Ended		6 Months Ended
	Jun. 26, 2015	Jun. 27, 2014	Jun. 26, 2015	Jun. 27, 2014	Apr. 30, 2015
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Share repurchase program					$ 2,000,000,000
Shares repurchased	$ 157,000,000	$ 130,000,000	$ 284,000,000	$ 257,000,000
Shares repurchased during the period (in shares)	4	4	8	9