Investments - Maturities of Available-for-sale and Held-to-maturity Securities (Details) $ in Millions	May 13, 2018 USD ($)
Available-for-sale, Cost Basis
Due in one year or less	$ 207
Due after one year through five years	687
Due after five years	20
Available-for-sale, cost basis, total	914
Available-for-sale, Fair Value
Due in one year or less	206
Due after one year through five years	672
Due after five years	19
Available-for-sale, recorded basis, total	897
Held-to-maturity
Due in one year or less	270
Due after one year through five years	0
Due after five years	0
Held-to-maturity, cost basis, total	$ 270