Fair Value Measurements (Fair Value Hierarchy) (Details) - Fair value, Measurements, Recurring [Member] - USD ($) $ in Millions	Jul. 02, 2017	Sep. 25, 2016
Assets, Fair Value Disclosure [Abstract]
Total	$ 744	$ 517
Level 1 Inputs [Member]
Assets, Fair Value Disclosure [Abstract]
Total		62
Level 2 Inputs [Member]
Assets, Fair Value Disclosure [Abstract]
Total	744	455
Money Market Funds [Member]
Assets, Fair Value Disclosure [Abstract]
Cash Equivalents, Fair Value Disclosure		62
Money Market Funds [Member] \| Level 1 Inputs [Member]
Assets, Fair Value Disclosure [Abstract]
Cash Equivalents, Fair Value Disclosure		62
Commercial Paper [Member]
Assets, Fair Value Disclosure [Abstract]
Cash Equivalents, Fair Value Disclosure		30
Marketable Securities - Available-for-sale	45	30
Commercial Paper [Member] \| Level 2 Inputs [Member]
Assets, Fair Value Disclosure [Abstract]
Cash Equivalents, Fair Value Disclosure		30
Marketable Securities - Available-for-sale	45	30
Municipal Notes Bonds [Member]
Assets, Fair Value Disclosure [Abstract]
Cash Equivalents, Fair Value Disclosure		46
Marketable Securities - Available-for-sale	144	26
Municipal Notes Bonds [Member] \| Level 2 Inputs [Member]
Assets, Fair Value Disclosure [Abstract]
Cash Equivalents, Fair Value Disclosure		46
Marketable Securities - Available-for-sale	144	26
Variable Rate Demand Obligation [Member]
Assets, Fair Value Disclosure [Abstract]
Marketable Securities - Available-for-sale	555	323
Variable Rate Demand Obligation [Member] \| Level 2 Inputs [Member]
Assets, Fair Value Disclosure [Abstract]
Marketable Securities - Available-for-sale	$ 555	$ 323

WHOLE FOODS MARKET INC 10-Q