Document and Entity Information - shares	9 Months Ended
	Sep. 30, 2019	Nov. 01, 2019
Entity Registrant Name	Tradeweb Markets Inc.
Entity Central Index Key	0001758730
Document Type	10-Q
Document Period End Date	Sep. 30, 2019
Amendment Flag	false
Current Fiscal Year End Date	--12-31
Entity Current Reporting Status	Yes
Entity Filer Category	Non-accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	true
Entity Ex Transition Period	true
Entity Shell Company	false
Document Fiscal Year Focus	2019
Document Fiscal Period Focus	Q3
Class A common stock
Entity Common Stock, Shares Outstanding		63,674,649
Class B common stock
Entity Common Stock, Shares Outstanding		96,933,192
Class C common stock
Entity Common Stock, Shares Outstanding		8,881,156
Class D common stock
Entity Common Stock, Shares Outstanding		52,947,070