Acquisitions and Dispositions Acquisitions and Dispositions - Pro Forma (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Business Acquisition [Line Items]
Actual revenue results included in consolidation	$ 773.0	$ 442.7
Actual net income results included in consolidation	32.5	10.5
Revenues	4,200.2	3,690.9	$ 3,683.2
Reported net income (loss) attributable to Brink's	105.2	16.0	29.0
Pro forma revenue results	4,238.6	4,031.6
Pro forma net income results	108.4	17.1
Transaction Costs	6.5	19.3	$ 7.9
PAI
Business Acquisition [Line Items]
Actual revenue results included in consolidation	98.8
Actual net income results included in consolidation	6.9
Pro forma revenue results	31.4	93.5
Pro forma net income results	2.5	1.0
G4S
Business Acquisition [Line Items]
Actual revenue results included in consolidation	674.2
Actual net income results included in consolidation	25.6
Pro forma revenue results	7.0	247.2
Pro forma net income results	$ 0.7	0.1
Rodoban
Business Acquisition [Line Items]
Actual revenue results included in consolidation		442.7
Actual net income results included in consolidation		$ 10.5