Segment Information - Disaggregation of Revenue (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Apr. 30, 2019	Apr. 30, 2018	Apr. 30, 2019	Apr. 30, 2018
Revenue from External Customer [Line Items]
Revenues	$ 3,272	$ 2,912	$ 5,790	$ 5,161
Small Business & Self-Employed
Revenue from External Customer [Line Items]
Revenues	887	747	2,628	2,279
Consumer
Revenue from External Customer [Line Items]
Revenues	2,150	1,949	2,701	2,439
Strategic Partner
Revenue from External Customer [Line Items]
Revenues	235	216	461	443
Online Ecosystem Subsegment | Small Business & Self-Employed
Revenue from External Customer [Line Items]
Revenues	439	318	1,204	865
Online Ecosystem Subsegment | Small Business & Self-Employed | QuickBooks
Revenue from External Customer [Line Items]
Revenues	260	183	708	500
Online Ecosystem Subsegment | Small Business & Self-Employed | Online Services
Revenue from External Customer [Line Items]
Revenues	179	135	496	365
Desktop Ecosystem Subsegment | Small Business & Self-Employed
Revenue from External Customer [Line Items]
Revenues	448	429	1,424	1,414
Desktop Ecosystem Subsegment | Small Business & Self-Employed | QuickBooks
Revenue from External Customer [Line Items]
Revenues	181	163	563	559
Desktop Ecosystem Subsegment | Small Business & Self-Employed | Desktop Services And Supplies
Revenue from External Customer [Line Items]
Revenues	267	266	861	855
Desktop Ecosystem Subsegment | Small Business & Self-Employed | QuickBooks Packaged Software
Revenue from External Customer [Line Items]
Revenues	$ 53	$ 47	$ 119	$ 117