Stockholders' Equity - Additional information (Details) $ / shares in Units, $ in Millions		6 Months Ended	12 Months Ended
	Jan. 20, 2022 shares	Jul. 31, 2022 shares	Jul. 31, 2024 USD ($) period $ / shares shares	Jul. 31, 2023 USD ($) shares	Jul. 31, 2022 USD ($) shares	Aug. 31, 2024 $ / shares	Aug. 20, 2024 USD ($)	Jul. 31, 2021 shares	Dec. 03, 2020 shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock repurchased during period (in shares) | $			$ 1,978	$ 1,967	$ 1,854
Common stock dividends, cash paid (in dollars per share) | $ / shares			$ 3.60
Common stock dividends | $			$ 1,000
Common stock, shares authorized (in shares)			750,000,000	750,000,000
Pool shares reduced for each share granted (in shares)			2.3
Pool shares increased for each share forfeited (in shares)		2.3	2.3
Shares available for grant (in shares)		26,260,000	27,317,000	19,026,000	26,260,000			16,851,000
Stock offering period, months, employee stock purchase plans			6 months
Stock accrual period, employee stock purchase plans, number of accrual periods | period			2
Stock offering period, number of months in accrual period			3 months
Percentage of lower of the closing price for stock on the first day last day of the offering period			85.00%
Shares issued during period for Employee Stock Purchase Plans (in shares)			360,028	399,975	326,961
Shares available for issuance under Employee Stock Purchase Plan (in shares)			1,963,952
Market price of common stock (in dollars per share) | $ / shares			$ 647.35
Computer software
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation expense | $			$ 0	$ 0	$ 1
Credit Karma
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares available for future issuance under assumed plan (in shares)									3,366,512
Stock Options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of years until options vest			7 years
Shares available for grant (in shares)			27,300,000
Unrecognized compensation cost | $			$ 131
Weighted-average vesting period			3 years 2 months 12 days
Stock Options | Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting period			3 years
Stock Options | Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting period			4 years
Restricted Stock Units (RSUs)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Percent of total share-based compensation expense			90.00%
Unrecognized compensation cost | $			$ 5,000
Weighted-average vesting period			2 years 10 months 24 days
Restricted Stock Units (RSUs) | Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting period			3 years
Restricted Stock Units (RSUs) | Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting period			4 years
Employee Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock, shares authorized (in shares)			25,800,000
Restated 2005 Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock, shares authorized (in shares)			171,700,000
Restated 2005 Plan | Stock Options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Pool shares reduced for each share granted (in shares)			1
Number of shares added back to plan when grants are forfeited (in shares)			1
Credit Karma Plan | Restricted Stock Units (RSUs)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Pool shares reduced for each share granted (in shares)	1
Number of shares added back to plan when grants are forfeited (in shares)	1
Subsequent Event
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock repurchase program, additional authorized amount (in shares) | $							$ 3,000
Dividend per share payable (in dollars per share) | $ / shares						$ 1.04
Current Program
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock repurchase program remaining authorized repurchase amount | $			$ 1,900
Common Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock repurchases under stock repurchase programs (in shares)			3,427,000	4,700,000	3,754,000