Condensed Consolidated Statements of Operations (Unaudited) - USD ($) shares in Millions, $ in Millions		3 Months Ended		9 Months Ended
		Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Income Statement [Abstract]
Revenues		$ 1,075.5	$ 970.5	$ 3,102.0	$ 2,669.3
Costs and expenses:
Cost of revenues		837.6	742.9	2,415.6	2,120.2
Selling, general and administrative expenses		161.9	141.4	472.0	429.1
Total costs and expenses		999.5	884.3	2,887.6	2,549.3
Other operating income (expense)		(1.8)	(9.8)	(5.2)	(18.4)
Operating profit		74.2	76.4	209.2	101.6
Interest expense		(27.6)	(27.1)	(83.0)	(70.3)
Interest and other nonoperating income (expense)		(0.7)	(12.8)	(1.6)	(31.4)
Income (loss) from continuing operations before tax		45.9	36.5	124.6	(0.1)
Provision for income taxes		22.9	58.9	59.2	3.5
Income (loss) from continuing operations		23.0	(22.4)	65.4	(3.6)
Loss from discontinued operations, net of tax		0.0	(0.1)	(0.1)	(0.9)
Net income (loss)		23.0	(22.5)	65.3	(4.5)
Less net income attributable to noncontrolling interests		4.0	1.4	9.7	4.7
Net income (loss) attributable to Brink’s		19.0	(23.9)	55.6	(9.2)
Amounts attributable to Brink’s
Continuing operations		19.0	(23.8)	55.7	(8.3)
Discontinued operations		0.0	(0.1)	(0.1)	(0.9)
Net income (loss) attributable to Brink’s		$ 19.0	$ (23.9)	$ 55.6	$ (9.2)
Basic:
Continuing operations (dollars per share)	[1]	$ 0.38	$ (0.47)	$ 1.12	$ (0.17)
Discontinued operations (dollar per share)	[1]	0	0	0	(0.02)
Net income (dollars per share)	[1]	0.38	(0.48)	1.12	(0.18)
Diluted:
Continuing operations (dollars per share)	[1]	0.38	(0.47)	1.11	(0.17)
Discontinued operations (dollar per share)	[1]	0	0	0	(0.02)
Net income (dollars per share)	[1]	$ 0.38	$ (0.48)	$ 1.10	$ (0.18)
Weighted-average shares
Basic (shares)		49.8	50.4	49.9	50.6
Diluted (shares)		50.3	50.4	50.4	50.6
Cash dividends paid per common share (dollars per share)		$ 0.20	$ 0.15	$ 0.55	$ 0.45

[1] Amounts may not add due to rounding.