Condensed Consolidated Statement of Equity (Unaudited) - USD ($) shares in Millions, $ in Millions		Total	Common Stock	Capital in Excess of Par Value	Retained Earnings	Accumulated Other Comprehensive Loss	Attributable to Noncontrolling Interests
Beginning balance at Dec. 31, 2016		$ 354.8	$ 50.0	$ 618.1	$ 576.0	$ (907.0)	$ 17.7
Beginning balance, Shares at Dec. 31, 2016			50.0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)		54.0			48.9		5.1
Other comprehensive income		46.5				47.2	(0.7)
Dividends to:
Brink’s common shareholders		(12.6)			(12.6)
Noncontrolling interests		(2.6)					(2.6)
Share-based compensation:
Compensation expense		8.5		8.5
Consideration from exercise of stock options		2.6	$ 0.0	2.6
Consideration from exercise of stock options, Shares			0.0
Other share-based benefit transactions		(8.4)	$ 0.4	(8.8)
Other share-based benefit transactions, shares			0.4
Ending balance at Jun. 30, 2017		442.8	$ 50.4	620.4	612.3	(859.8)	19.5
Ending balance, Shares at Jun. 30, 2017			50.4
Beginning balance at Dec. 31, 2017		338.2	$ 50.5	628.6	564.9	(926.6)	20.8
Beginning balance, Shares at Dec. 31, 2017			50.5
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)		(82.1)			(85.6)		3.5
Other comprehensive income		0.8				0.7	0.1
Dividends to:
Brink’s common shareholders		(15.2)			(15.2)
Noncontrolling interests		(1.9)					(1.9)
Share-based compensation:
Compensation expense		12.5		12.5
Consideration from exercise of stock options		0.8	$ 0.0	0.8
Consideration from exercise of stock options, Shares			0.0
Other share-based benefit transactions		(9.8)	$ 0.5	(10.3)
Other share-based benefit transactions, shares			0.5
Dispositions of noncontrolling interests		(0.4)					(0.4)
Ending balance at Jun. 30, 2018		245.1	$ 51.0	631.6	467.4	(927.0)	22.1
Ending balance, Shares at Jun. 30, 2018			51.0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Cumulative effect of change in accounting principle	[1]	2.2			3.3	(1.1)
Net income (loss)		(107.6)
Other comprehensive income		(11.4)				(10.4)
Ending balance at Jun. 30, 2018		$ 245.1	$ 51.0	$ 631.6	$ 467.4	$ (927.0)	$ 22.1
Ending balance, Shares at Jun. 30, 2018			51.0

[1] Effective January 1, 2018, we adopted the provisions of ASU 2014-09, Revenue From Contracts with Customers, ASU 2016-01, Recognition and Measurement of Financial Assets and Financial Liabilities, and ASU 2016-16, Intra-Entity Transfers of Assets Other Than Inventory. We recognized a cumulative effect adjustment to January 1, 2018 retained earnings as a result of adopting each of these standards. See Note 1 for further details of the impact of each standard.