v3.26.1
FINANCIAL INSTRUMENTS AND RISK MANAGEMENT - Schedule of Derivatives not Designated as Hedging Instruments (Details) - Not Designated as Hedging Instrument, Economic Hedge - USD ($)
$ in Millions
Jun. 30, 2026
Dec. 31, 2025
Location, Statement of Financial Position, Balance [Axis]: us-gaap:OtherAssetsCurrent | Foreign currency contracts    
Derivative Instruments, Gain (Loss) [Line Items]    
Asset Derivatives $ 3.8 $ 5.5
Location, Statement of Financial Position, Balance [Axis]: us-gaap:OtherAssetsCurrent | TRS    
Derivative Instruments, Gain (Loss) [Line Items]    
Asset Derivatives 94.3 7.2
Location, Statement of Financial Position, Balance [Axis]: cls:AccruedLiabilitiesAndOtherLiabilitiesAndProvisionsCurrent | Foreign currency contracts    
Derivative Instruments, Gain (Loss) [Line Items]    
Liability Derivatives 12.3 2.9
Location, Statement of Financial Position, Balance [Axis]: cls:AccruedLiabilitiesAndOtherLiabilitiesAndProvisionsCurrent | TRS    
Derivative Instruments, Gain (Loss) [Line Items]    
Liability Derivatives $ 0.0 $ 0.0