Condensed Consolidated Statements of Cash Flows (Unaudited) Condensed Consolidated Statements of Cash Flows (Parenthetical) - USD ($) $ in Millions	Oct. 31, 2018	Jul. 31, 2018	Oct. 31, 2017	Jul. 31, 2017
Statement of Cash Flows [Abstract]
Cash and cash equivalents	$ 1,084	$ 1,464	$ 529
Restricted cash and restricted cash equivalents included in funds held for customers	238	167	119	$ 172
Total cash, cash equivalents, restricted cash, and restricted cash equivalents at end of period	$ 1,322	$ 1,631	$ 648	$ 701