Debt (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023	Dec. 31, 2023
Debt Instrument [Line Items]
Short-term borrowings	$ 155.0		$ 151.7
Long-term Debt Types [Abstract]
Total long-term debt	3,434.9		3,379.6
Total Debt	3,589.9		3,531.3
Long-term Debt by Current and Noncurrent [Abstract]
Current liabilities	280.6		268.8
Noncurrent liabilities	3,309.3		3,262.5
Other Disclosures [Abstract]
Long-term revolving credit facilities: Borrowings	2,536.9	$ 1,961.1
Long-term revolving credit facilities: Repayments	2,470.8	$ 2,044.1
Brink's Capital credit facility
Other Disclosures [Abstract]
Long-term revolving credit facilities: Borrowings	1,877.5
Long-term revolving credit facilities: Repayments	1,962.4
Term Loan A | Senior Secured Credit Facility - Amended III
Long-term Debt Types [Abstract]
Long-term Debt	1,335.1		1,343.5
Other Disclosures [Abstract]
Debt issue costs	3.7		4.0
Senior unsecured notes | Six hundred million senior unsecured notes
Long-term Debt Types [Abstract]
Long-term Debt	995.0		994.4
Other Disclosures [Abstract]
Debt issue costs	5.0		5.6
Revolving Credit Facility
Long-term Debt Types [Abstract]
Debt	693.8		542.1
Other Non-US Dollar-denominated Facilities
Long-term Debt Types [Abstract]
Debt	175.1		265.8
Other Non-US Dollar-denominated Facilities | Brink's Capital credit facility
Long-term Debt Types [Abstract]
Debt	124.4		209.3
Financing leases
Long-term Debt Types [Abstract]
Financing leases	235.9		233.8
Short-term borrowings
Debt Instrument [Line Items]
Short-term borrowings	$ 155.0		$ 151.7