Information On Business Segments (Operating Income by Segment) (Details) - USD ($) $ in Millions		3 Months Ended		9 Months Ended
		Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Segment Reporting Information [Line Items]
Operating income	[1]	$ 57.5	$ 56.7	$ 121.0	$ 107.2
Interest expense		11.6	10.7	30.9	31.3
Interest income		(1.1)	(1.6)	(3.5)	(4.9)
Non-operating pension income		(2.6)	(2.0)	(7.1)	(6.2)
Other expense (income), net		0.6	(0.2)	1.6	(1.0)
Income before income tax		49.0	49.8	99.1	88.0
Operating Segment
Segment Reporting Information [Line Items]
Operating income	[1]	64.4	68.6	150.4	143.2
Corporate
Segment Reporting Information [Line Items]
Operating income	[1]	(6.9)	(11.9)	(29.4)	(36.0)
ACCO Brands North America | Operating Segment
Segment Reporting Information [Line Items]
Operating income	[1]	33.7	49.6	88.1	107.1
ACCO Brands EMEA | Operating Segment
Segment Reporting Information [Line Items]
Operating income	[1]	14.6	7.8	37.1	10.8
ACCO Brands International | Operating Segment
Segment Reporting Information [Line Items]
Operating income	[1]	$ 16.1	$ 11.2	$ 25.2	$ 25.3

[1] Operating income as presented in the segment table above is defined as i) net sales; ii) less cost of products sold; iii) less selling, general and administrative expenses; iv) less amortization of intangibles; and v) less restructuring charges.