Condensed Consolidated Statement of Equity (Unaudited) - USD ($) shares in Millions, $ in Millions		Total	Cumulative Effect, Period of Adoption, Adjustment	[1]	Common Stock	Capital in Excess of Par Value	Retained Earnings	Retained Earnings Cumulative Effect, Period of Adoption, Adjustment	[1]	Accumulated Other Comprehensive Loss	Noncontrolling Interests
Beginning balance at Dec. 31, 2020		$ 202.5	$ 0.5		$ 49.5	$ 671.8	$ 407.5	$ 0.5		$ (1,000.0)	$ 73.7
Beginning balance, Shares at Dec. 31, 2020					49.5
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Accounting Standards Update	[1]	Accounting Standards Update 2016-13 [Member]
Net income		$ 15.4					12.7				2.7
Other comprehensive income (loss)		(42.8)								(40.7)	(2.1)
Dividends to:
Brink’s common shareholders		(7.4)					(7.4)
Noncontrolling interests		(0.4)									(0.4)
Stock options and awards
Compensation expense		7.6				7.6
Consideration from exercise of stock options						2.3
Other share-based benefit transactions		(4.0)			$ 0.2	(4.2)
Other share-based benefit transactions, shares					0.2
Acquisitions with noncontrolling interests		51.4									51.4
Ending balance at Mar. 31, 2021		$ 225.1			$ 49.7	677.5	413.3			(1,040.7)	125.3
Ending balance, Shares at Mar. 31, 2021					49.7
Stock options and awards
Dividends (dollars per share)		$ 0.15
Beginning balance at Dec. 31, 2021		$ 252.6			$ 47.4	670.6	312.9			(907.9)	129.6
Beginning balance, Shares at Dec. 31, 2021					47.4
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income		74.2					71.3				2.9
Other comprehensive income (loss)		49.4								50.9	(1.5)
Dividends to:
Brink’s common shareholders		(9.5)					(9.5)
Noncontrolling interests		(1.2)									(1.2)
Stock options and awards
Compensation expense		7.1				7.1
Consideration from exercise of stock options		2.3
Other share-based benefit transactions		(2.8)			$ 0.2	(3.0)
Other share-based benefit transactions, shares					0.2
Ending balance at Mar. 31, 2022		$ 369.8			$ 47.6	$ 674.7	$ 374.7			$ (857.0)	$ 129.8
Ending balance, Shares at Mar. 31, 2022					47.6
Stock options and awards
Dividends (dollars per share)		$ 0.20

[1] Effective January 1, 2021, we adopted the provisions of ASU 2019-12, Income Taxes (Topic 740): Simplifying the Accounting for Income Taxes. We recognized a cumulative effect adjustment to January 1, 2021 retained earnings as a result of adopting this standard. See Note 1 for further details.