Income Taxes - Valuation Allowances (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Valuation Allowances [Roll Forward]
Beginning of year				$ 32.4				$ 47.4	$ 32.4	$ 47.4	$ 43.9
Expiring tax credits									(0.5)	(1.8)	(0.8)
Acquisitions and dispositions									(1.0)	(32.7)	(0.9)
Changes in judgment about deferred tax assets									1.9	(0.2)	(1.0)
Valuation and Qualifying Accounts Disclosure [Line Items]
Amounts attributable to Brink's Income (loss) from Continuing operations	(25.5)	28.8	0.9	(59.0)	23.9	28.4	12.1	1.6	(54.8)	66.0	102.3
Income (loss) from discontinued operations	(21.7)	(8.6)	0.7	0.5	17.0	(4.6)	(3.4)	(18.2)	(29.1)	(9.2)	(13.4)
Other comprehensive income (loss), net of tax									(181.5)	154.6	14.0
Foreign currency exchange effects									(2.9)	1.0	0.8
End of year	40.1				32.4				40.1	32.4	47.4
Valuation Allowance of Deferred Tax Assets [Member]
Valuation and Qualifying Accounts Disclosure [Line Items]
Amounts attributable to Brink's Income (loss) from Continuing operations									6.3	6.1	3.0
Income (loss) from discontinued operations									3.3	12.6	2.3
Other comprehensive income (loss), net of tax									$ 0.6	$ 0	$ 0.1