v2.4.1.9

Supplemental Guarantor Information Condensed Consolidated Statements of Comprehensive Income (Loss) (Details) (USD $) In Millions, unless otherwise specified | 12 Months Ended
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Dec. 31, 2014 | Dec. 31, 2013 | Dec. 31, 2012
Supplemental Guarantor Information [Line Items] |  |  |
Comprehensive Income (Loss), Net of Tax, Attributable to Parent | $ 234.6 us-gaap_ComprehensiveIncomeNetOfTax | $ 126.1 us-gaap_ComprehensiveIncomeNetOfTax | $ 121.5 us-gaap_ComprehensiveIncomeNetOfTax
Parent Guarantor [Member] |  |  |
Supplemental Guarantor Information [Line Items] |  |  |
Comprehensive Income (Loss), Net of Tax, Attributable to Parent | 234.6 us-gaap_ComprehensiveIncomeNetOfTax / dei_LegalEntityAxis = us-gaap_ParentCompanyMember | 126.1 us-gaap_ComprehensiveIncomeNetOfTax / dei_LegalEntityAxis = us-gaap_ParentCompanyMember | 121.5 us-gaap_ComprehensiveIncomeNetOfTax / dei_LegalEntityAxis = us-gaap_ParentCompanyMember
Subsidiary Issuer [Member] |  |  |
Supplemental Guarantor Information [Line Items] |  |  |
Comprehensive Income (Loss), Net of Tax, Attributable to Parent | 234.6 us-gaap_ComprehensiveIncomeNetOfTax / dei_LegalEntityAxis = us-gaap_SubsidiaryIssuerMember | 141.3 us-gaap_ComprehensiveIncomeNetOfTax / dei_LegalEntityAxis = us-gaap_SubsidiaryIssuerMember | 121.5 us-gaap_ComprehensiveIncomeNetOfTax / dei_LegalEntityAxis = us-gaap_SubsidiaryIssuerMember
Guarantor Subsidiaries [Member] |  |  |
Supplemental Guarantor Information [Line Items] |  |  |
Comprehensive Income (Loss), Net of Tax, Attributable to Parent | 484.6 us-gaap_ComprehensiveIncomeNetOfTax / dei_LegalEntityAxis = us-gaap_GuarantorSubsidiariesMember | 409.0 us-gaap_ComprehensiveIncomeNetOfTax / dei_LegalEntityAxis = us-gaap_GuarantorSubsidiariesMember | 322.8 us-gaap_ComprehensiveIncomeNetOfTax / dei_LegalEntityAxis = us-gaap_GuarantorSubsidiariesMember
Non-Guarantor Subsidiaries [Member] |  |  |
Supplemental Guarantor Information [Line Items] |  |  |
Comprehensive Income (Loss), Net of Tax, Attributable to Parent | 5.1 us-gaap_ComprehensiveIncomeNetOfTax / dei_LegalEntityAxis = us-gaap_NonGuarantorSubsidiariesMember | 4.8 us-gaap_ComprehensiveIncomeNetOfTax / dei_LegalEntityAxis = us-gaap_NonGuarantorSubsidiariesMember | 13.2 us-gaap_ComprehensiveIncomeNetOfTax / dei_LegalEntityAxis = us-gaap_NonGuarantorSubsidiariesMember
Co-Issuer [Member] |  |  |
Supplemental Guarantor Information [Line Items] |  |  |
Comprehensive Income (Loss), Net of Tax, Attributable to Parent | 0 us-gaap_ComprehensiveIncomeNetOfTax / dei_LegalEntityAxis = cdw_CoIssuerMember | 0 us-gaap_ComprehensiveIncomeNetOfTax / dei_LegalEntityAxis = cdw_CoIssuerMember | 0 us-gaap_ComprehensiveIncomeNetOfTax / dei_LegalEntityAxis = cdw_CoIssuerMember
Consolidating Adjustments [Member] |  |  |
Supplemental Guarantor Information [Line Items] |  |  |
Comprehensive Income (Loss), Net of Tax, Attributable to Parent | (724.3)us-gaap_ComprehensiveIncomeNetOfTax / dei_LegalEntityAxis = us-gaap_ConsolidationEliminationsMember | (555.1)us-gaap_ComprehensiveIncomeNetOfTax / dei_LegalEntityAxis = us-gaap_ConsolidationEliminationsMember | (457.5)us-gaap_ComprehensiveIncomeNetOfTax / dei_LegalEntityAxis = us-gaap_ConsolidationEliminationsMember
Consolidated [Member] |  |  |
Supplemental Guarantor Information [Line Items] |  |  |
Comprehensive Income (Loss), Net of Tax, Attributable to Parent | $ 234.6 us-gaap_ComprehensiveIncomeNetOfTax / dei_LegalEntityAxis = us-gaap_ConsolidatedEntitiesMember | $ 126.1 us-gaap_ComprehensiveIncomeNetOfTax / dei_LegalEntityAxis = us-gaap_ConsolidatedEntitiesMember | $ 121.5 us-gaap_ComprehensiveIncomeNetOfTax / dei_LegalEntityAxis = us-gaap_ConsolidatedEntitiesMember

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- Definition Amount after tax of increase (decrease) in equity from transactions and other events and circumstances from net income and other comprehensive income, attributable to parent entity. Excludes changes in equity resulting from investments by owners and distributions to owners. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Glossary Other Comprehensive Income -URI http://asc.fasb.org/extlink&oid=6519514 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Glossary Comprehensive Income -URI http://asc.fasb.org/extlink&oid=35737396 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 220 -SubTopic 10 -Section 45 -Paragraph 5 -URI http://asc.fasb.org/extlink&oid=36458714&loc=d3e557-108580 Reference 4: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Glossary Net Income -URI http://asc.fasb.org/extlink&oid=6518256 + Details
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