Accumulated Other Comprehensive Income Narrative (Details) (USD $) In Millions, unless otherwise specified	Sep. 30, 2013	Dec. 31, 2012
Accumulated Other Comprehensive Income (Loss), Net of Tax [Abstract]
Tax portion of net unrealized gain on investments	$ 1.0	$ 0.4

Accumulated Other Comprehensive Income Loss Available For Sale Securities Tax

No definition available.

Name:	akam_AccumulatedOtherComprehensiveIncomeLossAvailableForSaleSecuritiesTax
Namespace Prefix:	akam_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant