\documentclass{article}
\usepackage{enumitem}
\newlist{biglist}{itemize}{3}
\setlist[biglist,1]{leftmargin=0pt,labelwidth=0pt,labelsep=0pt,label=}
\setlist[biglist,2]{leftmargin=1em,labelwidth=0pt,labelsep=0pt,label=}
\setlist[biglist,3]{leftmargin=1em,labelwidth=0pt,labelsep=0pt,label=}
\begin{document}
\begin{biglist}
\item 3 - Mainframe \& minicomputer era languages \& derivatives
\begin{biglist}
\item 311 - Early or primitive languages
\begin{biglist}
\item 3111 - FLOW-MATIC
\item 3112 - AIMACO