Consolidated Statements of Comprehensive Income (Loss) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Statement of Comprehensive Income [Abstract]
Net income	$ 98.3	$ 181.9	$ 117.3
Benefit plan adjustments:
Benefit plan actuarial gains (losses)	(3.9)	177.6	189.4
Benefit plan prior service credit (costs)	(11.8)	61.7	(4.3)
Deferred profit sharing	0.4	(0.1)	(0.4)
Total benefit plan adjustments	(15.3)	239.2	184.7
Foreign currency translation adjustments	58.2	(19.0)	(58.9)
Gains (losses) on available-for-sale securities	4.2	(0.9)	(0.1)
Gains (losses) on cash flow hedges	(9.4)	37.6	19.1
Other comprehensive income before tax	37.7	256.9	144.8
Provision (benefit) for income taxes	(4.5)	55.9	55.3
Other comprehensive income	42.2	201.0	89.5
Comprehensive income	140.5	382.9	206.8
Less comprehensive income attributable to noncontrolling interests	8.3	5.0	9.5
Comprehensive income attributable to Brink’s	$ 132.2	$ 377.9	$ 197.3