Commitments and Contingencies - Pledged Assets (Details) - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016
Commitments and Contingencies Disclosure [Abstract]
Pledged assets	$ 1,400	$ 715

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