detail has 4 distinct synonyms spread across 3 of its 7 senses. Each sense below keeps its own list, because a synonym belongs to a meaning and not to a word: swapping one sense's substitute into another sense's sentence is how a thesaurus makes writing worse. WordNet records no antonym for it — antonymy is a relation between word forms rather than concepts, so it is deliberately sparse.
Counts are distinct word forms across every sense. A synonym that appears under three senses is counted once here and shown three times below, under each sense it belongs to.
an isolated fact that is considered separately from the whole
“several of the details are similar”
a small part that can be considered separately from the whole
“it was perfect in all details”
extended treatment of particulars
“the essay contained too much detail”
a crew of workers selected for a particular task
“a detail was sent to remove the fallen trees”
a temporary military unit
“the peacekeeping force includes one British contingent”
assign to a specific task
“The ambulances were detailed to the fire station”
Synonyms, antonyms and the broader and narrower relations for detail come from Princeton University’s WordNet. Full sources and licences.