Debt Investment Maturities (Detail)
$ in Millions
Mar. 31, 2016
USD ($)
Cost Basis  
Due in one year or less $ 43,753
Due after one year through five years 53,372
Due after five years through 10 years 2,266
Due after 10 years 1,216
Total 100,607
Estimated Fair Value  
Due in one year or less 43,745
Due after one year through five years 53,453
Due after five years through 10 years 2,275
Due after 10 years 1,280
Total $ 100,753