Acquisitions and Dispositions Acquisitions and Dispositions - Acquired Entities (Details)						12 Months Ended
	Apr. 01, 2021 USD ($)	Sep. 30, 2019	Jun. 14, 2019	Jun. 12, 2019	Jan. 04, 2019 USD ($) employee branch vehicle	Dec. 31, 2021 USD ($)	Dec. 31, 2020 USD ($) employee acquisition	Dec. 31, 2019 USD ($)	Mar. 09, 2020
Business Acquisition [Line Items]
Number of acquired operations | acquisition							4
G4S intercompany payments						$ 45,100,000	$ (114,500,000)	$ 35,000,000.0
Business Combination, Recognized Identifiable Assets Acquired, Goodwill, and Liabilities Assumed, Net [Abstract]
Restricted cash						376,400,000	322,000,000
Right-of-use assets, net						299,100,000	322,000,000.0
Goodwill						1,411,700,000	1,219,200,000	$ 784,600,000
PAI
Business Acquisition [Line Items]
Acquisition date	Apr. 01, 2021
Percentage of shares acquired	100.00%
Annual revenues							$ 94,000,000
Business Combination, Recognized Identifiable Assets Acquired, Goodwill, and Liabilities Assumed, Net [Abstract]
Purchase consideration - cash paid	$ 215,500,000
Fair value of purchase consideration	215,500,000
Cash	12,300,000
Accounts receivables	7,700,000
Other current assets	5,500,000
Property and Equipment, net	14,400,000
Intangible assets	95,000,000.0
Goodwill	126,800,000					$ 2,000,000
Other noncurrent assets	4,500,000
Current liabilities	(41,200,000)
Noncurrent liabilities	(9,500,000)
Fair value of net assets acquired	215,500,000
G4Si
Business Acquisition [Line Items]
Percentage of shares acquired									100.00%
G4S
Business Acquisition [Line Items]
Percentage of shares acquired						100.00%
Annual revenues						$ 800,000,000
G4S intercompany payments						114,000,000
Business Combination, Recognized Identifiable Assets Acquired, Goodwill, and Liabilities Assumed, Net [Abstract]
Purchase consideration - cash paid						816,900,000
Contingent consideration						22,000,000.0
Liabilities assumed from seller						2,900,000
Indemnification asset						(15,900,000)
Fair value of purchase consideration						825,900,000
Cash						244,400,000
Restricted cash						30,100,000
Accounts receivables						145,800,000
Other current assets						30,800,000
Property and Equipment, net						123,800,000
Right-of-use assets, net						77,500,000
Intangible assets						207,000,000.0
Goodwill						534,100,000
Other noncurrent assets						16,200,000
Current liabilities						(296,300,000)
Lease liability						(68,100,000)
Noncurrent liabilities						(103,900,000)
Fair value of net assets acquired						941,400,000
Fair value of noncontrolling interest						(115,500,000)
G4S | Europe
Business Combination, Recognized Identifiable Assets Acquired, Goodwill, and Liabilities Assumed, Net [Abstract]
Goodwill						191,000,000
G4S | Rest of World
Business Combination, Recognized Identifiable Assets Acquired, Goodwill, and Liabilities Assumed, Net [Abstract]
Goodwill						340,000,000
G4S | Latin America
Business Combination, Recognized Identifiable Assets Acquired, Goodwill, and Liabilities Assumed, Net [Abstract]
Goodwill						$ 3,000,000
G4S Tranche III
Business Acquisition [Line Items]
Percentage of shares acquired						100.00%
Rodoban
Business Acquisition [Line Items]
Acquisition date					Jan. 04, 2019
Percentage of shares acquired					100.00%
Entity Number of Employees | employee					2,900
Entity Number Of Branches | branch					13
Entity Number Of Armored Vehicles | vehicle					190
Business Combination, Recognized Identifiable Assets Acquired, Goodwill, and Liabilities Assumed, Net [Abstract]
Purchase consideration - cash paid					$ 135,700,000
Indemnification asset					(1,900,000)
Fair value of purchase consideration					133,800,000
Cash					1,400,000
Accounts receivables					8,900,000
Other current assets					500,000
Property and Equipment, net					2,400,000
Intangible assets					49,000,000.0
Goodwill					85,100,000
Other noncurrent assets					5,800,000
Current liabilities					(11,400,000)
Noncurrent liabilities					(7,900,000)
Fair value of net assets acquired					133,800,000
Other Acquisitions
Business Acquisition [Line Items]
Number of acquired operations | acquisition							3
Entity Number of Employees | employee							1,300
Business Combination, Recognized Identifiable Assets Acquired, Goodwill, and Liabilities Assumed, Net [Abstract]
Purchase consideration - cash paid							$ 60,600,000
Contingent consideration							1,600,000
Indemnification asset							(13,300,000)
Fair value of purchase consideration							48,900,000
Cash							6,500,000
Accounts receivables							4,500,000
Property and Equipment, net							7,100,000
Intangible assets							24,300,000
Goodwill							34,300,000
Other noncurrent assets							2,000,000.0
Current liabilities							(15,200,000)
Noncurrent liabilities							(14,600,000)
Fair value of net assets acquired							$ 48,900,000
BI
Business Acquisition [Line Items]
Acquisition date				Jun. 12, 2019
Percentage of shares acquired				100.00%
COMEF
Business Acquisition [Line Items]
Acquisition date			Jun. 14, 2019
Percentage of shares acquired			100.00%
TVS
Business Acquisition [Line Items]
Acquisition date		Sep. 30, 2019
Percentage of shares acquired		100.00%
Customer relationships | PAI
Business Acquisition [Line Items]
Remaining Amortization Period						10 years
Business Combination, Recognized Identifiable Assets Acquired, Goodwill, and Liabilities Assumed, Net [Abstract]
Intangible assets	60,000,000
Customer relationships | G4S
Business Acquisition [Line Items]
Remaining Amortization Period						15 years
Business Combination, Recognized Identifiable Assets Acquired, Goodwill, and Liabilities Assumed, Net [Abstract]
Intangible assets						$ 207,000,000
Customer relationships | Rodoban
Business Acquisition [Line Items]
Remaining Amortization Period						11 years
Business Combination, Recognized Identifiable Assets Acquired, Goodwill, and Liabilities Assumed, Net [Abstract]
Intangible assets					47,000,000
Developed technology | PAI
Business Acquisition [Line Items]
Remaining Amortization Period						12 years
Business Combination, Recognized Identifiable Assets Acquired, Goodwill, and Liabilities Assumed, Net [Abstract]
Intangible assets	26,000,000
Finite-lived trade names | PAI
Business Acquisition [Line Items]
Remaining Amortization Period						5 years
Business Combination, Recognized Identifiable Assets Acquired, Goodwill, and Liabilities Assumed, Net [Abstract]
Intangible assets	$ 9,000,000
Finite-lived trade names | Rodoban
Business Acquisition [Line Items]
Remaining Amortization Period						1 year
Business Combination, Recognized Identifiable Assets Acquired, Goodwill, and Liabilities Assumed, Net [Abstract]
Intangible assets					1,000,000
Noncompete Agreements | Rodoban
Business Acquisition [Line Items]
Remaining Amortization Period						5 years
Business Combination, Recognized Identifiable Assets Acquired, Goodwill, and Liabilities Assumed, Net [Abstract]
Intangible assets					$ 1,000,000