Financial Instruments (Cash and Cash Equivalents Fair Value Measurements) (Details) - USD ($) $ in Millions	Mar. 31, 2018	Dec. 30, 2017
Schedule of Investments [Line Items]
Total	$ 1,045	$ 1,185
Level 1
Schedule of Investments [Line Items]
Total	45	395
Level 2
Schedule of Investments [Line Items]
Total	887	682
Cash
Schedule of Investments [Line Items]
Total	113	108
Government money market funds | Level 1
Schedule of Investments [Line Items]
Total	45	395
Commercial paper | Level 2
Schedule of Investments [Line Items]
Total	$ 887	$ 682