Condensed Consolidated Statements of Comprehensive Income (Loss) (Unaudited) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Statement of Comprehensive Income [Abstract]
Net income (loss)	$ 14.0	$ (107.6)	$ 28.5	$ (82.1)
Benefit plan adjustments:
Benefit plan actuarial gains	9.0	22.9	20.3	37.7
Benefit plan prior service credits (costs)	(1.2)	1.1	(2.5)	0.3
Deferred profit sharing	(0.1)	0.0	(0.1)	0.0
Total benefit plan adjustments	7.9	24.0	17.9	38.0
Foreign currency translation adjustments	9.1	(31.8)	9.7	(30.8)
Gains (losses) on cash flow hedges	(10.6)	0.2	(18.5)	0.6
Other comprehensive income (loss) before tax	6.4	(7.6)	9.1	7.8
Provision (benefit) for income taxes	(0.7)	3.8	(0.2)	7.0
Other comprehensive income (loss)	7.1	(11.4)	9.3	0.8
Comprehensive income (loss)	21.1	(119.0)	37.8	(81.3)
Less comprehensive income (loss) attributable to noncontrolling interests	1.6	(0.7)	2.7	3.6
Comprehensive income (loss) attributable to Brink's	$ 19.5	$ (118.3)	$ 35.1	$ (84.9)