Accumulated Other Comprehensive Income (Loss) - Reclassification out of AOCI (Details) - USD ($) $ in Millions		3 Months Ended				6 Months Ended
		Jun. 30, 2024	Mar. 31, 2024	Jun. 30, 2023	Mar. 31, 2023	Jun. 30, 2024	Jun. 30, 2023
Reclassification Out of Accumulated Other Comprehensive Income [Line Items]
Cost of products sold		$ 285.7		$ 329.4		$ 534.2	$ 612.7
Other expense, net		0.2		0.3		0.8	(1.5)
Income tax (benefit) expense		2.2		(15.6)		1.2	(16.0)
Net Income (Loss)		(125.2)	$ (6.3)	26.4	$ (3.7)	(131.5)	22.7
Income (loss) before income tax		(127.4)		42.0		(132.7)	38.7
Amount Reclassified from Accumulated Other Comprehensive Income (Loss)
Reclassification Out of Accumulated Other Comprehensive Income [Line Items]
Net Income (Loss)		(3.7)		(1.1)		(4.9)	(1.8)
Unrecognized Pension and Other Post-retirement Benefit Costs | Amount Reclassified from Accumulated Other Comprehensive Income (Loss)
Reclassification Out of Accumulated Other Comprehensive Income [Line Items]
Income tax (benefit) expense		1.4		0.4		1.8	0.9
Net Income (Loss)		(4.1)		(1.3)		(5.5)	(2.4)
Amortization of net actuarial loss	[1]	(5.4)		(1.6)		(7.2)	(3.1)
Amortization of prior service cost	[1]	(0.1)		(0.1)		(0.1)	(0.2)
Income (loss) before income tax		(5.5)		(1.7)		(7.3)	(3.3)
Foreign exchange contracts | Derivative Financial Instruments | Amount Reclassified from Accumulated Other Comprehensive Income (Loss)
Reclassification Out of Accumulated Other Comprehensive Income [Line Items]
Cost of products sold		0.5		0.3		0.9	0.8
Income tax (benefit) expense		(0.1)		(0.1)		(0.3)	(0.2)
Net Income (Loss)		$ 0.4		$ 0.2		$ 0.6	$ 0.6

[1] These AOCI components are included in the computation of net periodic benefit (income) cost for pension and post-retirement plans including $3.6 million resulting from the wind-up of the ACCO Brands Canada Salaried and Hourly pension plans in the second of 2024. See "Note 5. Pension and Other Retiree Benefits" for additional details.