Acquisitions and Dispositions - Pro Forma (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Business Acquisition [Line Items]
Actual revenue results included in consolidation	$ 34.1	$ 0.0	$ 68.2	$ 0.0
Actual net income results included in consolidation	1.2	0.0	0.1	0.0
Revenues	1,216.2	1,133.9	2,401.6	2,207.9
Net income (loss) attributable to Brink’s	32.1	35.1	47.1	106.4
Pro forma revenue results	1,216.2	1,171.1	2,401.6	2,281.1
Pro forma net income results	32.1	41.0	47.1	112.9
NoteMachine
Business Acquisition [Line Items]
Actual revenue results included in consolidation	34.1	0.0	68.2	0.0
Actual net income results included in consolidation	1.2	0.0	0.1	0.0
Pro forma revenue results	0.0	37.2	0.0	73.2
Pro forma net income results	$ 0.0	$ 5.9	$ 0.0	$ 6.5