XML 66 R47.htm IDEA: XBRL DOCUMENT
v3.8.0.1

Description of Business and Summary of Significant Accounting Policies - Property Plant and Equipment (Details) - USD ($) $ in Millions | 12 Months Ended |
--- | --- | ---
Dec. 31, 2017 | Dec. 31, 2016
Property, Plant and Equipment [Line Items] |  |
Asset retirement liability (less than) | $ 2 | $ 1
Minimum | Machinery and equipment |  |
Property, Plant and Equipment [Line Items] |  |
Estimated useful life of property, plant and equipment | 5 years |
Minimum | Building and leasehold improvements |  |
Property, Plant and Equipment [Line Items] |  |
Estimated useful life of property, plant and equipment | 5 years |
Minimum | Computer and data processing equipment |  |
Property, Plant and Equipment [Line Items] |  |
Estimated useful life of property, plant and equipment | 3 years |
Minimum | Computer software |  |
Property, Plant and Equipment [Line Items] |  |
Estimated useful life of property, plant and equipment | 3 years |
Minimum | Furniture and fixtures |  |
Property, Plant and Equipment [Line Items] |  |
Estimated useful life of property, plant and equipment | 5 years |
Maximum | Machinery and equipment |  |
Property, Plant and Equipment [Line Items] |  |
Estimated useful life of property, plant and equipment | 10 years |
Maximum | Building and leasehold improvements |  |
Property, Plant and Equipment [Line Items] |  |
Estimated useful life of property, plant and equipment | 25 years |
Maximum | Computer and data processing equipment |  |
Property, Plant and Equipment [Line Items] |  |
Estimated useful life of property, plant and equipment | 5 years |
Maximum | Computer software |  |
Property, Plant and Equipment [Line Items] |  |
Estimated useful life of property, plant and equipment | 5 years |
Maximum | Furniture and fixtures |  |
Property, Plant and Equipment [Line Items] |  |
Estimated useful life of property, plant and equipment | 10 years |

X
- Definition The carrying amount of a liability for an asset retirement obligation. An asset retirement obligation is a legal obligation associated with the disposal or retirement of a tangible long-lived asset that results from the acquisition, construction or development, or the normal operations of a long-lived asset, except for certain obligations of lessees. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 410 -SubTopic 20 -Section 50 -Paragraph 1 -Subparagraph (c) -URI http://asc.fasb.org/extlink&oid=6392692&loc=d3e7535-110849 + Details
Name: | us-gaap_AssetRetirementObligation
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

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

X
- Definition Useful life of long lived, physical assets used in the normal conduct of business and not intended for resale, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days. Examples include, but not limited to, land, buildings, machinery and equipment, office equipment, furniture and fixtures, and computer equipment. + References No definition available. + Details
Name: | us-gaap_PropertyPlantAndEquipmentUsefulLife
Namespace Prefix: | us-gaap_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration

X
- Details
Name: | us-gaap_RangeAxis=us-gaap_MinimumMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_PropertyPlantAndEquipmentByTypeAxis=us-gaap_MachineryAndEquipmentMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_PropertyPlantAndEquipmentByTypeAxis=us-gaap_BuildingAndBuildingImprovementsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_PropertyPlantAndEquipmentByTypeAxis=us-gaap_ComputerEquipmentMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_PropertyPlantAndEquipmentByTypeAxis=cdw_ComputerSoftwareMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_PropertyPlantAndEquipmentByTypeAxis=us-gaap_FurnitureAndFixturesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RangeAxis=us-gaap_MaximumMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |