Commitments and Contingencies - Pledged Assets (Details) - USD ($) $ in Millions	Sep. 30, 2018	Dec. 31, 2017
Commitments and Contingencies Disclosure [Abstract]
Pledged assets	$ 688	$ 1,400

Securities And Fixed Assets Owned And Pledged As Collateral, Fair Value

No definition available.

Name:	amzn_SecuritiesAndFixedAssetsOwnedAndPledgedAsCollateralFairValue
Namespace Prefix:	amzn_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant