v3.26.3
Form N-1A Cover
Oct. 19, 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 Oct. 19, 2026
Prospectus Date Oct. 20, 2026