v3.26.1
Form N-1A Cover
Aug. 12, 2026
Prospectus [Line Items]  
Document Type 485BPOS
Amendment Flag false
Registrant Name First Trust Exchange-Traded Fund IV
Entity Central Index Key 0001517936
Entity Investment Company Type N-1A
Document Period End Date Aug. 12, 2026
Prospectus Date Aug. 12, 2026