Document And Entity Information - shares	2 Months Ended
	Sep. 30, 2020	Nov. 25, 2020
Document Information Line Items
Entity Registrant Name	Motion Acquisition Corp.
Document Type	10-Q
Current Fiscal Year End Date	--12-31
Amendment Flag	false
Entity Central Index Key	0001822359
Entity Current Reporting Status	No
Entity Filer Category	Non-accelerated Filer
Document Period End Date	Sep. 30, 2020
Document Fiscal Year Focus	2020
Document Fiscal Period Focus	Q3
Entity Small Business	true
Entity Emerging Growth Company	true
Entity Shell Company	true
Entity Ex Transition Period	false
Entity Incorporation, State or Country Code	DE
Entity File Number	001-39618
Document Transition Report	false
Entity Interactive Data Current	Yes
Class A Common Stock
Document Information Line Items
Entity Common Stock, Shares Outstanding		11,500,000
Class B Common Stock
Document Information Line Items
Entity Common Stock, Shares Outstanding		2,875,000