Consolidated Statements of Comprehensive Income (Loss) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Statement of Comprehensive Income [Abstract]
Net income (loss)	$ 33.2	$ (27.5)	$ 23.6
Benefit plan adjustments:
Benefit plan actuarial gains (losses)	27.1	35.4	(43.6)
Benefit plan prior service costs	(4.1)	(1.6)	(0.9)
Deferred profit sharing	0.4	(0.2)	0.0
Total benefit plan adjustments	23.4	33.6	(44.5)
Foreign currency translation adjustments	(0.1)	(45.2)	23.6
Unrealized net gains on available-for-sale securities	0.0	0.0	0.2
Gains (losses) on cash flow hedges	(19.0)	0.1	0.1
Other comprehensive income (loss) before tax	4.3	(11.5)	(20.6)
Provision (benefit) for income taxes	0.4	5.0	(1.8)
Other comprehensive income (loss)	3.9	(16.5)	(18.8)
Comprehensive income (loss)	37.1	(44.0)	4.8
Less comprehensive income attributable to noncontrolling interests	5.0	5.0	7.7
Comprehensive income (loss) attributable to Brink’s	$ 32.1	$ (49.0)	$ (2.9)