Cover Page - USD ($) $ in Billions	12 Months Ended
	Dec. 31, 2019	Feb. 21, 2020	Jun. 30, 2019
Cover page.
Document Type	10-K
Document Annual Report	true
Document Period End Date	Dec. 31, 2019
Document Transition Report	false
Entity File Number	001-37622
Entity Registrant Name	SQUARE, INC.
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	80-0429876
Entity Address, Address Line One	1455 Market Street
Entity Address, Address Line Two	Suite 600
Entity Address, City or Town	San Francisco
Entity Address, State or Province	CA
Entity Address, Postal Zip Code	94103
City Area Code	415
Local Phone Number	375-3176
Title of 12(b) Security	Class A Common Stock, $0.0000001 par value per share
Trading Symbol	SQ
Security Exchange Name	NYSE
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Public Float			$ 24.6
Class of Stock [Line Items]
Documents Incorporated by Reference	Portions of the registrant’s Definitive Proxy Statement relating to the Annual Meeting of Stockholders are incorporated by reference into Part III of this Annual Report on Form 10-K where indicated. Such Definitive Proxy Statement will be filed with the Securities and Exchange Commission within 120 days after the end of the registrant’s fiscal year ended December 31, 2019.
Entity Central Index Key	0001512673
Current Fiscal Year End Date	--12-31
Document Fiscal Year Focus	2019
Document Fiscal Period Focus	FY
Amendment Flag	false
Class A
Class of Stock [Line Items]
Entity Common Stock, Shares Outstanding (in shares)		354,826,967
Class B
Class of Stock [Line Items]
Entity Common Stock, Shares Outstanding (in shares)		80,407,753