Cash and Cash Equivalents, Investments, and Funds Receivable and Amounts Held for Customers - Type of Issue (Details) - USD ($)	Oct. 31, 2023	Jul. 31, 2023	Oct. 31, 2022	Jul. 31, 2022
Cash and Cash Equivalents Items [Line Items]
Funds receivable included on our condensed consolidated balance sheets in funds receivable and amounts held for customers not measured and recorded at fair value	$ 281,000,000	$ 216,000,000
Total cash, cash equivalents, restricted cash, and restricted cash equivalents at end of period	3,797,000,000	2,852,000,000	$ 2,140,000,000	$ 2,997,000,000
Available-for-sale securities:
Available-for-sale debt securities, amortized cost	726,000,000	1,023,000,000
Available-for-sale debt securities, fair value	718,000,000	1,014,000,000
Total cash, cash equivalents, restricted cash, restricted cash equivalents, and investments, amortized cost	4,523,000,000	3,875,000,000
Total cash, cash equivalents, restricted cash, restricted cash equivalents, and investments, fair value	4,515,000,000	3,866,000,000
Credit losses related to available-for-sale securities	0
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	3,797,000,000	2,852,000,000
Cash, cash equivalents, restricted cash, and restricted cash equivalents, fair value	3,797,000,000	2,852,000,000
Corporate notes
Available-for-sale securities:
Available-for-sale debt securities, amortized cost	552,000,000	811,000,000
Available-for-sale debt securities, fair value	547,000,000	805,000,000
U.S. agency securities
Available-for-sale securities:
Available-for-sale debt securities, amortized cost	174,000,000	212,000,000
Available-for-sale debt securities, fair value	$ 171,000,000	$ 209,000,000