Condensed Consolidated Statements of Comprehensive Income (Loss) (Unaudited) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Statement of Comprehensive Income [Abstract]
Net income	$ 35.1	$ 38.1	$ 53.4	$ 112.3
Benefit plan adjustments:
Benefit plan actuarial gains	0.0	12.7	3.1	23.2
Benefit plan prior service costs	(2.7)	(1.2)	(5.7)	(2.5)
Deferred profit sharing	0.3	0.0	0.3	0.0
Total benefit plan adjustments	(2.4)	11.5	(2.3)	20.7
Foreign currency translation adjustments	15.7	(62.6)	59.1	(30.5)
Unrealized net gains (losses) on available-for-sale securities	2.3	(0.3)	0.4	(0.7)
Gains on cash flow hedges	15.7	11.8	7.0	25.2
Other comprehensive income before tax	31.3	(39.6)	64.2	14.7
Provision (benefit) for income taxes	1.0	0.0	(2.1)	4.9
Other comprehensive income (loss)	30.3	(39.6)	66.3	9.8
Comprehensive income (loss)	65.4	(1.5)	119.7	122.1
Less comprehensive income (loss) attributable to noncontrolling interests	0.0	(2.0)	3.5	(0.6)
Comprehensive income attributable to Brink's	$ 65.4	$ 0.5	$ 116.2	$ 122.7