Retirement Benefits - Obligations and Funded Status (Details) $ in Millions	12 Months Ended
	Dec. 31, 2015 USD ($)	Dec. 31, 2014 USD ($) participant	Dec. 31, 2013 USD ($)
U.S. Plans
Changes in the benefit obligation [Roll Forward]
Benefit obligation at beginning of year	$ 904.1	$ 934.9
Service cost	0.0	0.0	$ 0.0
Interest cost	36.0	45.3	42.2
Participant contributions	0.0	0.0
Plan amendments	0.0	0.0
Plan combinations	0.0	0.0
Curtailments	0.0	0.0
Settlements(a)	0.0	(149.0)
Benefits paid	(51.0)	(44.9)
Sale of Brink’s Netherlands	0.0	0.0
Actuarial (gains) losses	(44.3)	117.8
Foreign currency exchange effects	0.0	0.0
Benefit obligation at end of year	844.8	904.1	934.9
Changes in plan assets [Roll Forward]
Fair value of plan assets at beginning of year	786.3	811.8
Return on assets – actual	(14.2)	80.6
Participant contributions	0.0	0.0
Employer contributions	0.3	87.8
Settlements(a)	0.0	(149.0)
Benefits paid	(51.0)	(44.9)
Sale of Brink’s Netherlands	0.0	0.0
Foreign currency exchange effects	0.0	0.0
Fair value of plan assets at end of year	721.4	786.3	811.8
Defined Benefit Plan, Funded Status of Plan [Abstract]
Funded status	(123.4)	(117.8)
Current liability, included in accrued liabilities	0.6	0.6
Noncurrent liability	122.8	117.2
Net pension liability	(123.4)	$ (117.8)
Number of participants | participant		4,300
Benefit plan net experience losses recognized in accumulated other comprehensive income (loss):
Beginning of year - net gains and losses	(340.4)	$ (323.6)
Net experience gains (losses) arising during the year	(24.5)	(101.1)
Reclassification adjustment for amortization of prior experience losses included in net income (loss)(a)	31.2	84.3
End of year - net gains and losses	(333.7)	(340.4)	(323.6)
Benefit plan prior service cost recognized in accumulated other comprehensive income (loss):
Beginning of year - net prior service (cost) credit	0.0	0.0
Prior service credit (cost) from plan amendments during the year	0.0	0.0
Reclassification adjustment for amortization of prior service cost included in net income (loss)(a)	0.0	0.0
End of year - net prior service (cost) credit	0.0	0.0	0.0
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]
Return on assets – expected	54.6	63.9	56.9
Amortization of losses	(31.2)	(28.2)	(45.1)
Amortization of prior service cost	0.0	0.0	0.0
U.S. and Mexican retirement plans	12.6	65.7	30.5
Non-U.S. Plans
Changes in the benefit obligation [Roll Forward]
Benefit obligation at beginning of year	283.1	390.4
Service cost	10.4	12.5	15.0
Interest cost	11.2	18.4	19.1
Participant contributions	0.4	4.2
Plan amendments	(2.4)	0.1
Plan combinations	1.2	0.0
Curtailments	0.0	(0.1)
Settlements(a)	0.0	0.0
Benefits paid	(19.5)	(24.2)
Sale of Brink’s Netherlands	0.0	(132.7)
Actuarial (gains) losses	14.8	59.7
Foreign currency exchange effects	(41.2)	(45.0)
Benefit obligation at end of year	262.8	283.1	390.4
Changes in plan assets [Roll Forward]
Fair value of plan assets at beginning of year	179.3	322.0
Return on assets – actual	4.3	23.8
Participant contributions	0.4	4.2
Employer contributions	24.1	31.0
Settlements(a)	0.0	0.0
Benefits paid	(19.5)	(24.2)
Sale of Brink’s Netherlands	0.0	(157.2)
Foreign currency exchange effects	(25.0)	(20.3)
Fair value of plan assets at end of year	164.8	179.3	322.0
Defined Benefit Plan, Funded Status of Plan [Abstract]
Funded status	(98.0)	(103.8)
Current liability, included in accrued liabilities	1.4	2.0
Noncurrent liability	96.6	101.8
Net pension liability	(98.0)	(103.8)
Benefit plan net experience losses recognized in accumulated other comprehensive income (loss):
Beginning of year - net gains and losses	(85.7)	(39.2)
Net experience gains (losses) arising during the year	(20.0)	(50.3)
Reclassification adjustment for amortization of prior experience losses included in net income (loss)(a)	10.7	3.8
End of year - net gains and losses	(95.0)	(85.7)	(39.2)
Benefit plan prior service cost recognized in accumulated other comprehensive income (loss):
Beginning of year - net prior service (cost) credit	(9.3)	(10.2)
Prior service credit (cost) from plan amendments during the year	(2.4)	0.1
Reclassification adjustment for amortization of prior service cost included in net income (loss)(a)	0.9	0.8
End of year - net prior service (cost) credit	(10.8)	(9.3)	(10.2)
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]
Return on assets – expected	9.5	14.4	12.9
Amortization of losses	(5.0)	(2.3)	(6.1)
Amortization of prior service cost	0.9	1.0	0.8
U.S. and Mexican retirement plans	23.7	26.1	30.7
Total
Changes in the benefit obligation [Roll Forward]
Benefit obligation at beginning of year	1,187.2	1,325.3
Service cost	10.4	12.5	15.0
Interest cost	47.2	63.7	61.3
Participant contributions	0.4	4.2
Plan amendments	(2.4)	0.1
Plan combinations	1.2	0.0
Curtailments	0.0	(0.1)
Settlements(a)	0.0	(149.0)
Benefits paid	(70.5)	(69.1)
Sale of Brink’s Netherlands	0.0	(132.7)
Actuarial (gains) losses	(29.5)	177.5
Foreign currency exchange effects	(41.2)	(45.0)
Benefit obligation at end of year	1,107.6	1,187.2	1,325.3
Changes in plan assets [Roll Forward]
Fair value of plan assets at beginning of year	965.6	1,133.8
Return on assets – actual	(9.9)	104.4
Participant contributions	0.4	4.2
Employer contributions	24.4	118.8
Settlements(a)	0.0	(149.0)
Benefits paid	(70.5)	(69.1)
Sale of Brink’s Netherlands	0.0	(157.2)
Foreign currency exchange effects	(25.0)	(20.3)
Fair value of plan assets at end of year	886.2	965.6	1,133.8
Defined Benefit Plan, Funded Status of Plan [Abstract]
Funded status	(221.4)	(221.6)
Current liability, included in accrued liabilities	2.0	2.6
Noncurrent liability	219.4	219.0
Net pension liability	(221.4)	(221.6)
Benefit plan net experience losses recognized in accumulated other comprehensive income (loss):
Beginning of year - net gains and losses	(426.1)	(362.8)
Net experience gains (losses) arising during the year	(44.5)	(151.4)
Reclassification adjustment for amortization of prior experience losses included in net income (loss)(a)	41.9	88.1
End of year - net gains and losses	(428.7)	(426.1)	(362.8)
Benefit plan prior service cost recognized in accumulated other comprehensive income (loss):
Beginning of year - net prior service (cost) credit	(9.3)	(10.2)
Prior service credit (cost) from plan amendments during the year	(2.4)	0.1
Reclassification adjustment for amortization of prior service cost included in net income (loss)(a)	0.9	0.8
End of year - net prior service (cost) credit	(10.8)	(9.3)	(10.2)
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]
Return on assets – expected	64.1	78.3	69.8
Amortization of losses	(36.2)	(30.5)	(51.2)
Amortization of prior service cost	0.9	1.0	0.8
U.S. and Mexican retirement plans	36.3	91.8	61.2
UMWA Plans
Changes in the benefit obligation [Roll Forward]
Benefit obligation at beginning of year	461.8	426.5
Service cost	0.0	0.0	0.0
Interest cost	17.1	17.9	19.7
Plan amendments	0.0	0.0
Curtailments	0.0	0.0
Benefits paid	(36.1)	(34.5)
Medicare subsidy received	0.1	0.6
Actuarial (gains) losses	9.8	(51.3)
Foreign currency exchange effects	0.0	0.0
Benefit obligation at end of year	433.1	461.8	426.5
Changes in plan assets [Roll Forward]
Fair value of plan assets at beginning of year	264.6	284.4
Return on assets – actual	(0.9)	14.9
Employer contributions	(0.3)	(0.8)
Benefits paid	(36.1)	(34.5)
Fair value of plan assets at end of year	227.4	264.6	284.4
Defined Benefit Plan, Funded Status of Plan [Abstract]
Funded status	(205.7)	(197.2)
Current liability, included in accrued liabilities	0.0	0.0
Noncurrent liability	205.7	197.2
Net pension liability	(205.7)	(197.2)
Benefit plan net experience losses recognized in accumulated other comprehensive income (loss):
Beginning of year - net gains and losses	(265.6)	(219.4)
Net experience gains (losses) arising during the year	(11.7)	(58.6)
Reclassification adjustment for amortization of prior experience losses included in net income (loss)(a)	15.5	12.4
End of year - net gains and losses	(261.8)	(265.6)	(219.4)
Benefit plan prior service cost recognized in accumulated other comprehensive income (loss):
Beginning of year - net prior service (cost) credit	51.1	55.7
Prior service credit (cost) from plan amendments during the year	0.0	0.0
Reclassification adjustment for amortization of prior service cost included in net income (loss)(a)	(4.6)	(4.6)
End of year - net prior service (cost) credit	46.5	51.1	55.7
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]
Return on assets – expected	20.6	22.2	20.8
Amortization of losses	(15.5)	(12.3)	(19.6)
Amortization of prior service cost	(4.6)	(4.6)	0.0
Curtailment (gain)	0.0	0.0	0.0
U.S. and Mexican retirement plans	7.4	3.4	18.5
Black Lung and Other Plans
Changes in the benefit obligation [Roll Forward]
Benefit obligation at beginning of year	66.2	48.9
Service cost	0.2	0.1
Interest cost	2.8	2.3
Plan amendments	0.7	0.0
Curtailments	(0.5)	0.0
Benefits paid	(6.3)	(7.4)
Medicare subsidy received	0.0	0.0
Actuarial (gains) losses	(0.4)	(23.2)
Foreign currency exchange effects	(2.3)	(0.9)
Benefit obligation at end of year	59.8	66.2	48.9
Changes in plan assets [Roll Forward]
Fair value of plan assets at beginning of year	0.0	0.0
Return on assets – actual	0.0	0.0
Employer contributions	6.3	7.4
Benefits paid	(6.3)	(7.4)
Fair value of plan assets at end of year	0.0	0.0	0.0
Defined Benefit Plan, Funded Status of Plan [Abstract]
Funded status	(59.8)	(66.2)
Current liability, included in accrued liabilities	6.3	6.3
Noncurrent liability	53.5	59.9
Net pension liability	(59.8)	(66.2)
Benefit plan net experience losses recognized in accumulated other comprehensive income (loss):
Beginning of year - net gains and losses	(29.0)	(6.3)
Net experience gains (losses) arising during the year	0.1	(23.2)
Reclassification adjustment for amortization of prior experience losses included in net income (loss)(a)	3.1	0.5
End of year - net gains and losses	(25.8)	(29.0)	(6.3)
Benefit plan prior service cost recognized in accumulated other comprehensive income (loss):
Beginning of year - net prior service (cost) credit	(6.0)	(7.7)
Prior service credit (cost) from plan amendments during the year	0.7	0.0
Reclassification adjustment for amortization of prior service cost included in net income (loss)(a)	1.8	1.7
End of year - net prior service (cost) credit	(3.5)	(6.0)	(7.7)
Black Lung and Other Plans, Medical
Changes in the benefit obligation [Roll Forward]
Service cost	0.2	0.1	0.3
Interest cost	2.8	2.3	1.9
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]
Return on assets – expected	0.0	0.0	0.0
Amortization of losses	(3.1)	(0.6)	(0.7)
Amortization of prior service cost	1.8	1.7	1.7
Curtailment (gain)	0.1	0.0	0.0
U.S. and Mexican retirement plans	7.8	4.7	4.6
Retirement benefits other than pension
Changes in the benefit obligation [Roll Forward]
Benefit obligation at beginning of year	528.0	475.4
Service cost	0.2	0.1	0.3
Interest cost	19.9	20.2	21.6
Plan amendments	0.7	0.0
Curtailments	(0.5)	0.0
Benefits paid	(42.4)	(41.9)
Medicare subsidy received	0.1	0.6
Actuarial (gains) losses	9.4	(74.5)
Foreign currency exchange effects	(2.3)	(0.9)
Benefit obligation at end of year	492.9	528.0	475.4
Changes in plan assets [Roll Forward]
Fair value of plan assets at beginning of year	264.6	284.4
Return on assets – actual	(0.9)	14.9
Employer contributions	6.0	6.6
Benefits paid	(42.4)	(41.9)
Fair value of plan assets at end of year	227.4	264.6	284.4
Defined Benefit Plan, Funded Status of Plan [Abstract]
Funded status	(265.5)	(263.4)
Current liability, included in accrued liabilities	6.3	6.3
Noncurrent liability	259.2	257.1
Net pension liability	(265.5)	(263.4)
Benefit plan net experience losses recognized in accumulated other comprehensive income (loss):
Beginning of year - net gains and losses	(294.6)	(225.7)
Net experience gains (losses) arising during the year	(11.6)	(81.8)
Reclassification adjustment for amortization of prior experience losses included in net income (loss)(a)	18.6	12.9
End of year - net gains and losses	(287.6)	(294.6)	(225.7)
Benefit plan prior service cost recognized in accumulated other comprehensive income (loss):
Beginning of year - net prior service (cost) credit	45.1	48.0
Prior service credit (cost) from plan amendments during the year	0.7	0.0
Reclassification adjustment for amortization of prior service cost included in net income (loss)(a)	(2.8)	(2.9)
End of year - net prior service (cost) credit	43.0	45.1	48.0
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]
Return on assets – expected	20.6	22.2	20.8
Amortization of losses	(18.6)	(12.9)	(20.3)
Amortization of prior service cost	(2.8)	(2.9)	1.7
Curtailment (gain)	0.1	0.0	0.0
U.S. and Mexican retirement plans	$ 15.2	8.1	$ 23.1
Netherlands CIT Operations
Benefit plan net experience losses recognized in accumulated other comprehensive income (loss):
Reclassification adjustment for amortization of prior experience losses included in net income (loss)(a)		$ 5.0