CAPITAL STOCK - Narrative (Details) $ in Millions		1 Months Ended						3 Months Ended	12 Months Ended
	Sep. 03, 2023	Sep. 30, 2024 shares	Mar. 31, 2024 shares	Oct. 31, 2023 USD ($)	Jun. 30, 2023 shares	Jul. 31, 2022 shares	Apr. 30, 2022 shares	Aug. 31, 2023 shares	Dec. 31, 2024 USD ($) vote shares	Dec. 31, 2023 USD ($) shares	Dec. 31, 2022 USD ($)	Oct. 30, 2024 shares	Apr. 25, 2024 vote	Dec. 12, 2023 shares	Dec. 08, 2022 shares	Dec. 31, 2021 USD ($)
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Preferred stock, votes | vote									1
Preferred stock, shares issued (in shares)									0
Multiple voting per share | vote													25
SBC cash settlement | $									$ 84.6	$ 66.7	$ 0.0
Secondary Offering | Onex Corporation
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Common stock, shares, issued (in shares)								18,600,000
Long-term Incentive Plan
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Share-based compensation arrangement, common share issuance per vested award (in shares)									1
Share-based compensation arrangement by share-based payment award, number of shares authorized (in shares)									29,000,000.0
Common stock, shares authorized (in shares)									9,600,000
RSU and PSU
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Share-based compensation arrangement, common share issuance per vested award (in shares)									1
SBC cash settlement | $									$ 84.6	7.7
Share-based payment arrangement, cash used to settle award | $										$ 49.8
RSU and PSU | Celestica Share Unit Plan (CSUP)
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Share-based compensation arrangement, common share issuance per vested award (in shares)									1
PSUs
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Share-based payment award, awards granted, percentage of target									100.00%
Share-based compensation arrangement, fair value assumptions, premium percentage									120.00%	118.00%	116.00%
Share-based compensation arrangement, equity instruments other than options, vested in period, fair value | $									$ 136.2	$ 39.2	$ 15.5
Vesting period									3 years
Share-based compensation award, shares outstanding (in shares)									3,100,000	4,600,000
PSUs | Minimum
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Share-based payment award, awards granted, percentage of target									0.00%
PSUs | Maximum
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Share-based payment award, awards granted, percentage of target									200.00%
RSUs
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Share-based compensation arrangement, equity instruments other than options, vested in period, fair value | $									$ 90.3	$ 41.0	28.1
Vesting period									3 years
Share-based compensation award, shares outstanding (in shares)									2,100,000	3,200,000
RSUs | Director
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Share-based compensation award, shares outstanding (in shares)									30,000.00	100,000
RSUs | Director | Mr. Ryan
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Share-based compensation arrangement by equity instruments other than options, settlement (in shares)							30,000.00
Deferred Stock Unit (DSUs)
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Share-based compensation arrangement, common share issuance per vested award (in shares)	1								1
Share-based compensation arrangement, equity instruments other than options, vested in period, fair value | $									$ 16.9	$ 19.2	$ 2.6
Vesting period									3 years
Share-based compensation award, shares outstanding (in shares)									700,000	1,100,000
Deferred Stock Unit (DSUs) | Onex Corporation
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Share-based payment arrangement, cash used to settle award | $				$ 9.2
Deferred Stock Unit (DSUs) | Director | Mr. DiMaggio
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Share-based compensation arrangement by equity instruments other than options, settlement (in shares)			300,000
Deferred Stock Unit (DSUs) | Director | Deepak Chopra
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Share-based compensation arrangement by equity instruments other than options, settlement (in shares)		100,000
Deferred Stock Unit (DSUs) | Director | Ms. Perry
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Share-based compensation arrangement by equity instruments other than options, settlement (in shares)					200,000
Deferred Stock Unit (DSUs) | Director | Mr. Etherington
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Share-based compensation arrangement by equity instruments other than options, settlement (in shares)					500,000
Deferred Stock Unit (DSUs) | Director | Mr. Ryan
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Share-based compensation arrangement by equity instruments other than options, settlement (in shares)						300,000
Employee Stock Option
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Vesting period									4 years
Share-Based Compensation Arrangement by Share-Based Payment Award, Expiration Period									10 years
2022 NCIB
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Share repurchase program, authorized, number of shares (in shares)															8,800,000
Accrual for repurchase of stock under automatic share purchase plan | $																$ 7.5
2023 NCIB
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Share repurchase program, authorized, number of shares (in shares)														11,800,000
Accrual for repurchase of stock under automatic share purchase plan | $										$ 2.7
Contractual maximum quantity for cancellation, share amount (in shares)										100,000
2023 SBC
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Contractual maximum quantity for cancellation, share amount (in shares)										300,000
2024 NCIB
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Share repurchase program, authorized, number of shares (in shares)												8,600,000
Accrual for repurchase of stock under automatic share purchase plan | $									$ 2.8
Share repurchase program, remaining authorized, number of shares (in shares)									8,300,000