Investments - Maturities of Available for Sale and Held to Maturity Securities (Details) (USD $) In Millions, unless otherwise specified	Feb. 16, 2014
Available-For-Sale, Cost Basis
Due in one year or less	$ 296
Due after one year through five years	1,019
Due after five years	22
Available-For-Sale, Cost Basis, Total	1,337
Available-For-Sale, Fair Value
Due in one year or less	296
Due after one year through five years	1,021
Due after five years	22
Available-for-sale, Recorded Basis, Total	1,339
Held-To-Maturity
Due in one year or less	13
Due after one year through five years	0
Due after five years	0
Held-To-Maturity, Cost Basis, Total	$ 13