Annual report pursuant to Section 13 and 15(d)

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Narrative (Details)

v3.24.0.1
SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Narrative (Details)
shares in Millions
 3 Months Ended 12 Months Ended
Jun. 30, 2023
USD ($)
Jun. 30, 2022
USD ($)
investment
Dec. 31, 2023
USD ($)
segment
shares
Dec. 31, 2022
USD ($)
shares
Dec. 31, 2021
USD ($)
shares
Aug. 07, 2023
USD ($)
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]            
Number of reportable segments | segment     3      
Number of operating segments | segment     3      
Contract assets     $ 23,300,000      
Advertising costs from continuing operations     67,000,000 $ 70,100,000 $ 70,200,000  
Depreciation and amortization     619,800,000 568,600,000 489,600,000  
Goodwill and intangible asset impairment     0 0 0  
Carrying value of investment       74,500,000 56,400,000 $ 88,900,000
Unrealized gain on investment     7,000,000      
Unrealized loss on investment       13,300,000 64,000,000  
Equity investment gain $ 6,200,000 $ 27,500,000        
Equity investments | investment   2        
Foreign currency transaction loss     3,600,000 1,800,000    
Foreign currency transaction gain         2,600,000  
Fair value of debt     5,300,000,000 4,800,000,000    
Long term debt carrying amount     5,500,000,000 5,300,000,000    
Variable interest entity, maximum exposure to loss     300,000 300,000    
Redemption premium     0      
Property and Equipment            
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]            
Depreciation and amortization     $ 360,100,000 323,400,000 $ 304,000,000  
Minimum | Computer Software Intangible Asset            
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]            
Property, plant and equipment useful life     3 years      
Maximum | Computer Software Intangible Asset            
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]            
Property, plant and equipment useful life     7 years      
Data Processing Equipment Capitalized Internal Use Software and Systems Costs | Minimum            
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]            
Property, plant and equipment useful life     3 years      
Data Processing Equipment Capitalized Internal Use Software and Systems Costs | Maximum            
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]            
Property, plant and equipment useful life     7 years      
Building            
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]            
Property, plant and equipment useful life     40 years      
Other Capitalized Property Plant and Equipment | Minimum            
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]            
Property, plant and equipment useful life     3 years      
Other Capitalized Property Plant and Equipment | Maximum            
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]            
Property, plant and equipment useful life     7 years      
Other Current Assets            
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]            
Income taxes receivable, current     $ 40,900,000 55,300,000    
Restricted cash     34,500,000 27,000,000    
Other Current Liabilities            
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]            
Restricted cash     34,500,000 27,000,000    
Legal fees     $ 79,600,000 $ 71,300,000    
Stock Options            
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]            
Antidilutive stock options excluded from computation of earnings per share (in shares) | shares     0.7 0.6 0.0  
Total Workforce Solutions | Revenue Benchmark | Segment Concentration Risk            
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]            
Largest segment's percent of total operating revenue     44.00%      
Other Income            
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]            
Foreign currency transaction loss     $ 3,800,000      
Foreign currency transaction gain       $ 200,000 $ 800,000