Cash and Cash Equivalents, Investments, and Funds Held for Customers - Type of issue (Details) - USD ($) $ in Millions	Jan. 31, 2022	Jul. 31, 2021	Jan. 31, 2021	Jul. 31, 2020
Cash and Cash Equivalents Items [Line Items]
Total cash, cash equivalents, restricted cash, and restricted cash equivalents at end of period	$ 1,433	$ 2,819	$ 2,178	$ 6,697
Available-for-sale securities:
Available-for-sale debt securities, amortized cost	360	1,504
Available-for-sale debt securities:	356	1,508
Total cash and cash equivalents, investments, and funds held for customers, amortized cost	1,793	4,323
Total cash and cash equivalents, investments, and funds held for customers, fair value	1,789	4,327
Total cash, cash equivalents, restricted cash, and restricted cash equivalents
Cash and Cash Equivalents Items [Line Items]
Total cash, cash equivalents, restricted cash, and restricted cash equivalents at end of period	1,433	2,819
Cash, cash equivalents, restricted cash, and restricted cash equivalents, fair value	1,433	2,819
Municipal bonds
Available-for-sale securities:
Available-for-sale debt securities, amortized cost	0	37
Available-for-sale debt securities:	0	38
Corporate notes
Available-for-sale securities:
Available-for-sale debt securities, amortized cost	327	1,397
Available-for-sale debt securities:	324	1,400
U.S. agency securities
Available-for-sale securities:
Available-for-sale debt securities, amortized cost	33	70
Available-for-sale debt securities:	$ 32	$ 70