Document and Entity Information shares in Millions	3 Months Ended
	Mar. 31, 2019 shares
Document and Entity Information [Abstract]
Document Type	10-Q
Entity Registrant Name	SERVICENOW, INC.
Trading Symbol	NOW
Entity Central Index Key	0001373715
Document Period End Date	Mar. 31, 2019
Amendment Flag	false
Document Fiscal Year Focus	2019
Document Fiscal Period Focus	Q1
Current Fiscal Year End Date	--12-31
Entity Filer Category	Large Accelerated Filer
Entity Emerging Growth Company	false
Entity Small Business	false
Entity Common Stock, Shares Outstanding	184.7