Segment information narrative (Details)	6 Months Ended
Jun. 30, 2014
Segment Reporting Information, Revenue for Reportable Segment [Abstract]
Major Customers Percentage Of Total Revenues Minimum	10.00%

Percentage of revenue generated from a single external customer that accounts for 10 percent or more of an entity's revenues, minimum percentage.

No definition available.

Name:	gild_MajorCustomersPercentageOfTotalRevenuesMinimum
Namespace Prefix:	gild_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration