v3.26.1
Average Annual Total Returns
12 Months Ended 56 Months Ended
Aug. 31, 2025
Dec. 31, 2024
Dec. 31, 2024
S&P 500® Index (reflects no deduction for fees, expenses or taxes)[Member]      
Prospectus [Line Items]      
Average Annual Return, Percent   25.02% 18.64%
FT Vest U.S. Equity Deep Buffer ETF - May      
Prospectus [Line Items]      
Average Annual Return, Percent   12.99% 6.60%
Performance Inception Date May 15, 2020    
FT Vest U.S. Equity Deep Buffer ETF - May | After Taxes on Distributions      
Prospectus [Line Items]      
Average Annual Return, Percent   12.99% 6.60%
FT Vest U.S. Equity Deep Buffer ETF - May | After Taxes on Distributions and Sales      
Prospectus [Line Items]      
Average Annual Return, Percent   7.69% 5.16%