Cover Page - shares	3 Months Ended
	Mar. 31, 2020	May 01, 2020
Cover [Abstract]
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Mar. 31, 2020
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 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
Class of Stock [Line Items]
Entity Central Index Key	0001512673
Current Fiscal Year End Date	--12-31
Document Fiscal Year Focus	2020
Document Fiscal Period Focus	Q1
Amendment Flag	false
Class A
Class of Stock [Line Items]
Entity Common Stock, Shares Outstanding (in shares)		362,988,307
Class B
Class of Stock [Line Items]
Entity Common Stock, Shares Outstanding (in shares)		76,362,944