XML 146 R120.htm IDEA: XBRL DOCUMENT
v3.20.4

Segment and Geographic Information - Revenue By Segment (Details) - USD ($) $ in Millions | 12 Months Ended
--- | ---
Dec. 31, 2020 | Dec. 31, 2019 | Dec. 31, 2018
Disclosure of operating segments [line items] |  |  |
Revenue | $ 5,748.1 | $ 5,888.3 | $ 6,633.2
ATS |  |  |
Disclosure of operating segments [line items] |  |  |
Revenue | $ 2,086.3 | $ 2,285.6 | $ 2,209.7
Percentage of entity's revenue (percent) | 36.00% | 39.00% | 33.00%
CCS |  |  |
Disclosure of operating segments [line items] |  |  |
Revenue | $ 3,661.8 | $ 3,602.7 | $ 4,423.5
Percentage of entity's revenue (percent) | 64.00% | 61.00% | 67.00%
Communications |  |  |
Disclosure of operating segments [line items] |  |  |
Percentage of entity's revenue (percent) | 42.00% | 40.00% | 41.00%
Enterprise |  |  |
Disclosure of operating segments [line items] |  |  |
Percentage of entity's revenue (percent) | 22.00% | 21.00% | 26.00%

X
- Definition Line items represent concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes of the table. + References No definition available. + Details
Name: | ifrs-full_DisclosureOfOperatingSegmentsLineItems
Namespace Prefix: | ifrs-full_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition The percentage of the entity's revenue. [Refer: Revenue] + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Name IFRS -Number 8 -IssueDate 2020-01-01 -Paragraph 34 -URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=8&code=ifrs-tx-2020-en-r&anchor=para_34&doctype=Standard -URIDate 2020-01-01 + Details
Name: | ifrs-full_PercentageOfEntitysRevenue
Namespace Prefix: | ifrs-full_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition The amount of revenue from contracts with customers. A customer is a party that has contracted with an entity to obtain goods or services that are an output of the entity’s ordinary activities in exchange for consideration. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Name IFRS -Number 15 -IssueDate 2020-01-01 -Paragraph 113 -Subparagraph a -URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=15&code=ifrs-tx-2020-en-r&anchor=para_113_a&doctype=Standard -URIDate 2020-01-01 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Name IFRS -Number 15 -IssueDate 2020-01-01 -Paragraph 114 -URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=15&code=ifrs-tx-2020-en-r&anchor=para_114&doctype=Standard -URIDate 2020-01-01 + Details
Name: | ifrs-full_RevenueFromContractsWithCustomers
Namespace Prefix: | ifrs-full_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Details
Name: | ifrs-full_SegmentsAxis=cls_AdvancedTechnologySolutionsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | ifrs-full_SegmentsAxis=cls_ConnectivityCloudSolutionsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | ifrs-full_SegmentsAxis=cls_CommunicationsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | ifrs-full_SegmentsAxis=cls_EnterpriseMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |