Fair Value Measurements - Recurring Basis (Details) - USD ($) $ in Millions	Oct. 31, 2021	Jul. 31, 2021
Assets:
Cash equivalents, primarily money market funds and time deposits	$ 2,864	$ 2,562
Available-for-sale debt securities:	584	1,508
Long-term debt	2,037	2,034
Senior Unsecured Notes
Assets:
Long-term debt	1,990
Fair value, measurements, recurring
Assets:
Cash equivalents, primarily money market funds and time deposits	696	1,660
Available-for-sale debt securities:	584	1,508
Total assets measured at fair value on a recurring basis	1,280	3,168
Fair value, measurements, recurring \| Senior Unsecured Notes
Assets:
Senior unsecured notes	1,972	1,986
Fair value, measurements, recurring \| Level 1
Assets:
Cash equivalents, primarily money market funds and time deposits	696	1,660
Available-for-sale debt securities:	0	0
Total assets measured at fair value on a recurring basis	696	1,660
Fair value, measurements, recurring \| Level 1 \| Senior Unsecured Notes
Assets:
Senior unsecured notes	0	0
Fair value, measurements, recurring \| Level 2
Assets:
Cash equivalents, primarily money market funds and time deposits	0	0
Available-for-sale debt securities:	584	1,508
Total assets measured at fair value on a recurring basis	584	1,508
Fair value, measurements, recurring \| Level 2 \| Senior Unsecured Notes
Assets:
Senior unsecured notes	1,972	1,986
Fair value, measurements, recurring \| Municipal bonds
Assets:
Available-for-sale debt securities:	0	38
Fair value, measurements, recurring \| Municipal bonds \| Level 1
Assets:
Available-for-sale debt securities:	0	0
Fair value, measurements, recurring \| Municipal bonds \| Level 2
Assets:
Available-for-sale debt securities:	0	38
Fair value, measurements, recurring \| Corporate notes
Assets:
Available-for-sale debt securities:	544	1,400
Fair value, measurements, recurring \| Corporate notes \| Level 1
Assets:
Available-for-sale debt securities:	0	0
Fair value, measurements, recurring \| Corporate notes \| Level 2
Assets:
Available-for-sale debt securities:	544	1,400
Fair value, measurements, recurring \| U.S. agency securities
Assets:
Available-for-sale debt securities:	40	70
Fair value, measurements, recurring \| U.S. agency securities \| Level 1
Assets:
Available-for-sale debt securities:	0	0
Fair value, measurements, recurring \| U.S. agency securities \| Level 2
Assets:
Available-for-sale debt securities:	$ 40	$ 70

Fair value portion of probable future economic benefits obtained or controlled by an entity as a result of past transactions or events.

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Amount of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

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Fair value portion of currency on hand as well as demand deposits with banks or financial institutions. Includes other kinds of accounts that have the general characteristics of demand deposits. Also includes short-term, highly liquid investments that are both readily convertible to known amounts of cash and so near their maturity that they present insignificant risk of changes in value because of changes in interest rates.

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Fair value portion of debt instrument payable, including, but not limited to, notes payable and loans payable.

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Amount, after unamortized (discount) premium and debt issuance costs, of long-term debt. Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations.

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