Restructuring (Restructuring Charges) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Restructuring Cost and Reserve [Line Items]
Restructuring charges	$ 11.7	$ 21.7	$ 5.4
Operating Segments | ACCO Brands North America
Restructuring Cost and Reserve [Line Items]
Restructuring charges	6.2	5.5	1.1
Operating Segments | ACCO Brands EMEA
Restructuring Cost and Reserve [Line Items]
Restructuring charges	4.9	11.2	0.0
Operating Segments | ACCO Brands International
Restructuring Cost and Reserve [Line Items]
Restructuring charges	0.6	5.0	4.3
Employee termination costs
Restructuring Cost and Reserve [Line Items]
Restructuring charges	8.3	18.2	5.2
Termination of lease agreements
Restructuring Cost and Reserve [Line Items]
Restructuring charges	3.2	2.4	$ 0.2
Restructuring and Related Cost, Expected Cost Remaining	0.4
Other
Restructuring Cost and Reserve [Line Items]
Restructuring charges	$ 0.2	$ 1.1