Nature of Operations and Significant Accounting Policies - Share Repurchases (Details) - USD ($) shares in Millions	3 Months Ended		9 Months Ended
	Sep. 25, 2015	Sep. 26, 2014	Sep. 25, 2015	Sep. 26, 2014	Apr. 30, 2015
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Share repurchase program					$ 2,000,000,000
Shares repurchased	$ 262,000,000	$ 131,000,000	$ 546,000,000	$ 388,000,000
Shares repurchased during the period (in shares)	9	4	17	13