Document And Entity Information	6 Months Ended
Jun. 30, 2011	Aug. 10, 2011 Class A Common Shares [Member]	Aug. 10, 2011 Class B Common Shares [Member]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Jun. 30, 2011
Document Fiscal Year Focus	2011
Document Fiscal Period Focus	Q2
Entity Registrant Name	CDW Corp
Entity Central Index Key	0001402057
Current Fiscal Year End Date	--12-31
Entity Filer Category	Non-accelerated Filer
Entity Common Stock, Shares Outstanding		100,000	912,076

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