Goodwill and Identifiable Intangible Assets - Summary of Changes in Net Carrying Amount Goodwill By Segment (Details) - USD ($) $ in Millions		3 Months Ended	6 Months Ended
	May 31, 2024	Jun. 30, 2024	Jun. 30, 2024
Goodwill [Roll Forward]
Beginning balance			$ 590.0
Goodwill impairment	$ (127.5)	$ (127.5)	(127.5)
Foreign currency translation			(11.2)
Ending balance		451.3	451.3
ACCO Brands Americas
Goodwill [Roll Forward]
Beginning balance			383.6
Goodwill impairment			(127.5)
Foreign currency translation			(1.5)
Ending balance		254.6	254.6
ACCO Brands International
Goodwill [Roll Forward]
Beginning balance			206.4
Goodwill impairment			0.0
Foreign currency translation			(9.7)
Ending balance		$ 196.7	$ 196.7