Cash and Cash Equivalents, Investments, and Funds Held for Customers - Classification on Balance Sheets (Details) - USD ($) $ in Millions	Jan. 31, 2022	Jul. 31, 2021	Jan. 31, 2021
Cash and Cash Equivalents Items [Line Items]
Cash and cash equivalents	$ 1,257	$ 2,562	$ 1,952
Available-for-sale debt securities, amortized cost	360	1,504
Total cash and cash equivalents, investments, and funds held for customers, amortized cost	1,793	4,323
Cash equivalents:	1,257	2,562
Available-for-sale debt securities, fair value	356	1,508
Total cash and cash equivalents, investments, and funds held for customers, fair value	1,789	4,327
Investments
Cash and Cash Equivalents Items [Line Items]
Available-for-sale debt securities, amortized cost	158	1,305
Available-for-sale debt securities, fair value	157	1,308
Funds held for customers
Cash and Cash Equivalents Items [Line Items]
Available-for-sale debt securities, amortized cost	378	456
Available-for-sale debt securities, fair value	$ 375	$ 457