Balance Sheet Details and Other Financial Information - Supplemental Cash Flow Information (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Supplemental Cash Flow Elements [Abstract]
Income taxes paid	$ 176.8us-gaap_IncomeTaxesPaid	$ 194.1us-gaap_IncomeTaxesPaid	$ 226.1us-gaap_IncomeTaxesPaid
Supplemental non-cash investing activities:
Equipment transfers from inventories to property, plant and equipment	$ 27.2isrg_TransferfromInventory	$ 13.1isrg_TransferfromInventory	$ 22.3isrg_TransferfromInventory

The amount of cash paid during the current period to foreign, federal, state, and local authorities as taxes on income.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 230

-SubTopic 10

-Section 50

-Paragraph 2

-URI http://asc.fasb.org/extlink&oid=6367179&loc=d3e4297-108586

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 230

-SubTopic 10

-Section 45

-Paragraph 25

-Subparagraph (f)

-URI http://asc.fasb.org/extlink&oid=31042434&loc=d3e3536-108585

Name:	us-gaap_IncomeTaxesPaid
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration