Investments - Maturities of Available for Sale and Held to Maturity Securities (Details) (USD $) In Millions, unless otherwise specified	May 10, 2015
Available-For-Sale, Cost Basis
Due in one year or less	$ 303
Due after one year through five years	1,215
Due after five years	48
Available-For-Sale, Cost Basis, Total	1,566
Available-For-Sale, Fair Value
Due in one year or less	303
Due after one year through five years	1,219
Due after five years	50
Available-for-sale, Recorded Basis, Total	1,572
Held-To-Maturity
Due in one year or less	170
Due after one year through five years	0
Due after five years	0
Held-To-Maturity, Cost Basis, Total	$ 170