Accumulated Other Comprehensive Income (Loss) - Reclassification out of AOCI (Parenthetical) (Details) - Pension - USD ($) $ in Millions		3 Months Ended		6 Months Ended
		Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
United States
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Net periodic benefit (income) cost	[1]	$ (0.7)	$ (0.4)	$ (1.4)	$ (0.8)
International
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Net periodic benefit (income) cost	[1]	5.7	$ 0.9	$ 7.0	$ 1.7
International | ACCO Brands International
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Net periodic benefit (income) cost		$ 3.6

[1] The components of net periodic benefit (income) cost, other than service cost, are included in the line "Non-operating pension expense" in the Consolidated Statements of (Loss) Income.