Debt Investment Maturities (Detail) $ in Millions	Mar. 31, 2021 USD ($)
Adjusted Cost Basis
Due in one year or less	$ 17,466
Due after one year through five years	65,306
Due after five years through 10 years	28,540
Due after 10 years	2,571
Debt investments, Adjusted Cost Basis	113,883
Estimated Fair Value
Due in one year or less	17,496
Due after one year through five years	68,168
Due after five years through 10 years	29,478
Due after 10 years	2,607
Total	$ 117,749