Income Taxes - Valuation Allowances (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2011	Sep. 30, 2011	Jun. 30, 2011	Mar. 31, 2011	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Valuation Allowances [Roll Forward]
Beginning of year				$ 43.9				$ 45.9	$ 43.9	$ 45.9	$ 45.4
Expiring tax credits									(0.8)	(0.3)	(0.6)
Acquisitions and dispositions									(0.9)	0.3	(10.0)
Changes in judgment about deferred tax assets									(1.0)	(8.2)	(0.9)
Valuation and Qualifying Accounts Disclosure [Line Items]
Amounts attributable to Brink's Income (loss) from Continuing operations	32.6	19.5	33.8	20.9	23.3	35.6	14.0	23.6	106.8	96.5	81.6
Income (loss) from discontinued operations	(4.7)	(6.0)	(3.3)	(3.9)	(7.5)	(4.8)	(6.1)	(3.6)	(17.9)	(22.0)	(24.5)
Other comprehensive income (loss), net of tax									14.0	(179.6)	(26.7)
Foreign currency exchange effects									0.8	(1.4)	(1.9)
End of year	47.4				43.9				47.4	43.9	45.9
Valuation Allowance of Deferred Tax Assets [Member]
Valuation and Qualifying Accounts Disclosure [Line Items]
Amounts attributable to Brink's Income (loss) from Continuing operations									3.4	7.6	14.9
Income (loss) from discontinued operations									1.9	0	(1.1)
Other comprehensive income (loss), net of tax									$ 0.1	$ 0	$ 0.1