Condensed Consolidated Statements of Comprehensive Income (Loss) (Unaudited) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Statement of Comprehensive Income [Abstract]
Net income	$ 49.4	$ 22.6	$ 102.8	$ 134.9
Benefit plan adjustments:
Benefit plan actuarial gains	4.2	10.1	7.3	33.3
Benefit plan prior service costs	(2.8)	(1.3)	(8.5)	(3.8)
Deferred profit sharing	(0.2)	0.0	0.1	0.0
Total benefit plan adjustments	1.2	8.8	(1.1)	29.5
Foreign currency translation adjustments	(41.0)	(42.2)	18.1	(72.7)
Unrealized net gains on available-for-sale securities	7.9	0.7	8.3	0.0
Gains on cash flow hedges	6.9	12.2	13.9	37.4
Other comprehensive income (loss) before tax	(25.0)	(20.5)	39.2	(5.8)
Provision for income taxes	5.7	12.6	3.6	17.5
Other comprehensive income (loss)	(30.7)	(33.1)	35.6	(23.3)
Comprehensive income (loss)	18.7	(10.5)	138.4	111.6
Less comprehensive income (loss) attributable to noncontrolling interests	2.3	(0.6)	5.8	(1.2)
Comprehensive income (loss) attributable to Brink's	$ 16.4	$ (9.9)	$ 132.6	$ 112.8