Condensed Consolidated Statements of Cash Flows (Unaudited) Condensed Consolidated Statements of Cash Flows (Parenthetical) - USD ($) $ in Millions	Jan. 31, 2019	Jul. 31, 2018	Jan. 31, 2018	Jul. 31, 2017
Statement of Cash Flows [Abstract]
Cash and cash equivalents	$ 1,075	$ 1,464	$ 478
Restricted cash and restricted cash equivalents included in funds held for customers	234	167	222	$ 172
Total cash, cash equivalents, restricted cash, and restricted cash equivalents at end of period	$ 1,309	$ 1,631	$ 700	$ 701