Income Taxes (Details) - USD ($) $ in Millions	12 Months Ended
	Jul. 31, 2016	Jul. 31, 2015	Jul. 31, 2014
Current:
Federal	$ 401	$ 253	$ 358
State	33	20	21
Foreign	13	7	10
Total current	447	280	389
Deferred:
Federal	(42)	14	51
State	(7)	1	5
Foreign	(1)	4	2
Total deferred	(50)	19	58
Total provision for income taxes from continuing operations	397	299	447
Income Statement [Abstract]
United States	1,205	716	1,276
Foreign	(2)	(4)	24
Income from continuing operations before income taxes	1,203	712	1,300
Effective Income Tax Rate Reconciliation, Amount [Abstract]
Income from continuing operations before income taxes	1,203	712	1,300
Statutory federal income tax	421	249	455
State income tax, net of federal benefit	17	15	17
Federal research and experimentation credits	(33)	(19)	(7)
Domestic production activities deduction	(34)	(19)	(25)
Share-based compensation	16	15	8
Effects of non-U.S. operations	11	12	1
Non-deductible goodwill	0	40	0
Other, net	(1)	6	(2)
Total provision for income taxes from continuing operations	397	299	447
Deferred tax assets:
Accruals and reserves not currently deductible	33	24
Deferred revenue	56	12
Deferred rent	14	10
Accrued and deferred compensation	55	52
Loss and tax credit carryforwards	51	44
Share-based compensation	62	52
Net basis difference in investments held for sale	0	122
Other, net	11	7
Total deferred tax assets	282	323
Deferred tax liabilities:
Intangible assets	86	87
Property and equipment	24	20
Total deferred tax liabilities	110	107
Total net deferred tax assets	172	216
Valuation allowance	(40)	(30)
Total net deferred tax assets, net of valuation allowance	132	186
Deferred Tax Assets, Net [Abstract]
Current deferred income taxes	0	231
Long-term deferred income taxes	139	5
Long-term deferred income taxes included in other long-term obligations	(7)	(50)
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward]
Gross unrecognized tax benefits, beginning balance	56	40	39
Increases related to tax positions from prior fiscal years, including acquisitions	7	15	4
Decreases related to tax positions from prior fiscal years	(7)	(1)	(8)
Increases related to tax positions taken during current fiscal year	15	5	5
Settlements with tax authorities	(11)	(3)	0
Gross unrecognized tax benefits, ending balance	60	56	40
Income Taxes (Textuals)
Income tax effects allocated directly to equity, employee stock options	$ 59	85	$ 82
Federal statutory income tax rate	35.00%
Discrete tax benefit due to changes in federal tax law	$ 12	11
Total net deferred tax assets, net of valuation allowance	132	186
Unrecognized tax benefits net of related deferred tax assets	40
Favorable net impact to income tax expense due to recognition of tax benefits	40
Domestic Country
Income Taxes (Textuals)
Operating loss carryforwards	19
State and Local Jurisdiction
Deferred tax liabilities:
Valuation allowance	(5)
Total net deferred tax assets, net of valuation allowance	8
Income Taxes (Textuals)
Operating loss carryforwards	156
Total net deferred tax assets, net of valuation allowance	8
Foreign Tax Authority | Inland Revenue, Singapore (IRAS)
Income Taxes (Textuals)
Operating loss carryforwards	76
Capital Loss Carryforward | State and Local Jurisdiction
Operating Loss Carryforwards [Line Items]
Operating loss carryforwards, valuation allowance	2
Research Tax Credit Carryforward | State and Local Jurisdiction
Income Taxes (Textuals)
Deferred tax assets, tax credit carryforwards	52
Amount of carryforward, if realized, to be recognized as additional paid in capital	11
Financial Services
Deferred tax assets:
Net basis difference in investments held for sale		122
Intuit Websites and Intuit Financial Services
Income Taxes (Textuals)
Deferred tax assets, capital loss carryforwards		4
Intuit Websites and Intuit Financial Services | Capital Loss Carryforward
Deferred tax liabilities:
Valuation allowance		(1)
Income Taxes (Textuals)
Valuation allowance, deferred tax asset, increase (decrease), amount		$ 2
Demandforce, QuickBase, and Quicken
Operating Loss Carryforwards [Line Items]
Income tax expense (benefit) from discontinued operations	$ 179