Supplemental Guarantor Information Condensed Consolidating Balance Sheets (Details) (USD $) In Millions, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Supplemental Guarantor Information [Line Items]
Cash and cash equivalents	$ 344.5	$ 188.1	$ 37.9	$ 99.9
Accounts receivable, net of allowance for doubtful accounts	1,561.1us-gaap_AccountsReceivableNetCurrent	1,451.0us-gaap_AccountsReceivableNetCurrent
Merchandise inventory	337.5us-gaap_InventoryNet	382.0us-gaap_InventoryNet
Miscellaneous receivables	155.6us-gaap_OtherReceivablesNetCurrent	146.3us-gaap_OtherReceivablesNetCurrent
Prepaid expenses and other	54.7	46.1
Total current assets	2,453.4us-gaap_AssetsCurrent	2,213.5us-gaap_AssetsCurrent
Property and equipment, net	137.2us-gaap_PropertyPlantAndEquipmentNet	131.1us-gaap_PropertyPlantAndEquipmentNet
Equity Method Investments	86.7us-gaap_EquityMethodInvestments	0us-gaap_EquityMethodInvestments
Goodwill	2,217.6us-gaap_Goodwill	2,220.3us-gaap_Goodwill	2,209.3us-gaap_Goodwill
Other intangible assets, net	1,168.8	1,328.0
Deferred financing costs, net	33.0	30.1	53.2
Other assets	3.2us-gaap_OtherAssetsNoncurrent	1.6us-gaap_OtherAssetsNoncurrent
Total assets	6,099.9us-gaap_Assets	5,924.6us-gaap_Assets
Accounts payable-trade	704.0us-gaap_AccountsPayableTradeCurrent	662.8us-gaap_AccountsPayableTradeCurrent
Accounts payable-inventory financing	332.1cdw_AccountsPayableInventoryFinancing	256.6cdw_AccountsPayableInventoryFinancing
Current maturities of long-term debt	15.4us-gaap_LongTermDebtCurrent	45.4us-gaap_LongTermDebtCurrent
Deferred revenue	81.3us-gaap_DeferredRevenueCurrent	94.8us-gaap_DeferredRevenueCurrent
Total current liabilities	1,468.0us-gaap_LiabilitiesCurrent	1,402.6us-gaap_LiabilitiesCurrent
Debt	3,174.6us-gaap_LongTermDebtNoncurrent	3,205.8us-gaap_LongTermDebtNoncurrent
Deferred income taxes	475.0	563.5
Other liabilities	45.8us-gaap_OtherLiabilitiesNoncurrent	41.0us-gaap_OtherLiabilitiesNoncurrent
Total long-term liabilities	3,695.4us-gaap_LiabilitiesNoncurrent	3,810.3us-gaap_LiabilitiesNoncurrent
Total shareholders' (deficit) equity	936.5us-gaap_StockholdersEquity	711.7us-gaap_StockholdersEquity	136.5us-gaap_StockholdersEquity	(7.3)us-gaap_StockholdersEquity
Total liabilities and shareholders' (deficit) equity	6,099.9	5,924.6
Parent Guarantor [Member]
Supplemental Guarantor Information [Line Items]
Cash and cash equivalents	0	0	0	0
Accounts receivable, net of allowance for doubtful accounts	0	0
Merchandise inventory	0	0
Miscellaneous receivables	0	0
Prepaid expenses and other	0	0
Total current assets	0	0
Property and equipment, net	0	0
Equity Method Investments	0
Goodwill	0	0
Other intangible assets, net	0	0
Deferred financing costs, net	0	0
Other assets	4.3	4.9
Investments in and advances to subsidiaries	932.2	706.8
Total assets	936.5	711.7
Accounts payable-trade	0	0
Accounts payable-inventory financing	0	0
Current maturities of long-term debt	0	0
Deferred revenue	0	0
Accrued expenses	0	0
Total current liabilities	0	0
Debt	0	0
Deferred income taxes	0	0
Other liabilities	0	0
Total long-term liabilities	0	0
Total shareholders' (deficit) equity	936.5	711.7
Total liabilities and shareholders' (deficit) equity	936.5	711.7
Subsidiary Issuer [Member]
Supplemental Guarantor Information [Line Items]
Cash and cash equivalents	346.4	196.5	48.0	102.1
Accounts receivable, net of allowance for doubtful accounts	0	0
Merchandise inventory	0	0
Miscellaneous receivables	56.1	49.9
Prepaid expenses and other	11.0	10.7
Total current assets	413.5	257.1
Property and equipment, net	80.5	69.7
Equity Method Investments	86.7
Goodwill	751.8	751.9
Other intangible assets, net	320.0	338.5
Deferred financing costs, net	33.0	30.1
Other assets	3.2	1.4
Investments in and advances to subsidiaries	2,784.5	2,909.4
Total assets	4,473.2	4,358.1
Accounts payable-trade	23.9	21.4
Accounts payable-inventory financing	0	0
Current maturities of long-term debt	15.4	45.4
Deferred revenue	0	0
Accrued expenses	137.8	163.5
Total current liabilities	177.1	230.3
Debt	3,174.6	3,205.8
Deferred income taxes	146.7	178.3
Other liabilities	42.6	36.9
Total long-term liabilities	3,363.9	3,421.0
Total shareholders' (deficit) equity	932.2	706.8
Total liabilities and shareholders' (deficit) equity	4,473.2	4,358.1
Guarantor Subsidiaries [Member]
Supplemental Guarantor Information [Line Items]
Cash and cash equivalents	0	0	0	15.8
Accounts receivable, net of allowance for doubtful accounts	1,479.1	1,375.9
Merchandise inventory	333.9	378.9
Miscellaneous receivables	93.3	91.0
Prepaid expenses and other	46.0	33.4
Total current assets	1,952.3	1,879.2
Property and equipment, net	55.5	59.6
Equity Method Investments	0
Goodwill	1,439.0	1,439.0
Other intangible assets, net	843.6	982.8
Deferred financing costs, net	0	0
Other assets	0.4	0.1
Investments in and advances to subsidiaries	0	0
Total assets	4,290.8	4,360.7
Accounts payable-trade	671.9	637.3
Accounts payable-inventory financing	332.1	256.6
Current maturities of long-term debt	0	0
Deferred revenue	79.9	89.9
Accrued expenses	193.6	175.1
Total current liabilities	1,277.5	1,158.9
Debt	0	0
Deferred income taxes	331.3	388.4
Other liabilities	3.7	3.6
Total long-term liabilities	335.0	392.0
Total shareholders' (deficit) equity	2,678.3	2,809.8
Total liabilities and shareholders' (deficit) equity	4,290.8	4,360.7
Non-Guarantor Subsidiaries [Member]
Supplemental Guarantor Information [Line Items]
Cash and cash equivalents	24.6	14.0	9.8	8.1
Accounts receivable, net of allowance for doubtful accounts	82.0	75.1
Merchandise inventory	3.6	3.1
Miscellaneous receivables	6.2	5.4
Prepaid expenses and other	1.5	5.1
Total current assets	117.9	102.7
Property and equipment, net	1.2	1.8
Equity Method Investments	0
Goodwill	26.8	29.4
Other intangible assets, net	5.2	6.7
Deferred financing costs, net	0	0
Other assets	1.4	0.9
Investments in and advances to subsidiaries	0	0
Total assets	152.5	141.5
Accounts payable-trade	34.7	26.5
Accounts payable-inventory financing	0	0
Current maturities of long-term debt	0	0
Deferred revenue	1.4	4.9
Accrued expenses	7.9	7.5
Total current liabilities	44.0	38.9
Debt	0	0
Deferred income taxes	1.3	1.6
Other liabilities	1.0	1.4
Total long-term liabilities	2.3	3.0
Total shareholders' (deficit) equity	106.2	99.6
Total liabilities and shareholders' (deficit) equity	152.5	141.5
Co-Issuer [Member]
Supplemental Guarantor Information [Line Items]
Cash and cash equivalents	0	0	0	0
Accounts receivable, net of allowance for doubtful accounts	0	0
Merchandise inventory	0	0
Miscellaneous receivables	0	0
Prepaid expenses and other	0	0
Total current assets	0	0
Property and equipment, net	0	0
Equity Method Investments	0
Goodwill	0	0
Other intangible assets, net	0	0
Deferred financing costs, net	0	0
Other assets	0	0
Investments in and advances to subsidiaries	0	0
Total assets	0	0
Accounts payable-trade	0	0
Accounts payable-inventory financing	0	0
Current maturities of long-term debt	0	0
Deferred revenue	0	0
Accrued expenses	0	0
Total current liabilities	0	0
Debt	0	0
Deferred income taxes	0	0
Other liabilities	0	0
Total long-term liabilities	0	0
Total shareholders' (deficit) equity	0	0
Total liabilities and shareholders' (deficit) equity	0	0
Consolidating Adjustments [Member]
Supplemental Guarantor Information [Line Items]
Cash and cash equivalents	(26.5)	(22.4)	(19.9)	(26.1)
Accounts receivable, net of allowance for doubtful accounts	0	0
Merchandise inventory	0	0
Miscellaneous receivables	0	0
Prepaid expenses and other	(3.8)	(3.1)
Total current assets	(30.3)	(25.5)
Property and equipment, net		0
Equity Method Investments	0
Goodwill	0	0
Other intangible assets, net	0	0
Deferred financing costs, net	0	0
Other assets	(6.1)	(5.7)
Investments in and advances to subsidiaries	(3,716.7)	(3,616.2)
Total assets	(3,753.1)	(3,647.4)
Accounts payable-trade	(26.5)	(22.4)
Accounts payable-inventory financing	0	0
Current maturities of long-term debt	0	0
Deferred revenue	0	0
Accrued expenses	(4.1)	(3.1)
Total current liabilities	(30.6)	(25.5)
Debt	0	0
Deferred income taxes	(4.3)	(4.8)
Other liabilities	(1.5)	(0.9)
Total long-term liabilities	(5.8)	(5.7)
Total shareholders' (deficit) equity	(3,716.7)	(3,616.2)
Total liabilities and shareholders' (deficit) equity	(3,753.1)	(3,647.4)
Consolidated [Member]
Supplemental Guarantor Information [Line Items]
Cash and cash equivalents	344.5	188.1	37.9	99.9
Accounts receivable, net of allowance for doubtful accounts	1,561.1	1,451.0
Merchandise inventory	337.5	382.0
Miscellaneous receivables	155.6	146.3
Prepaid expenses and other	54.7	46.1
Total current assets	2,453.4	2,213.5
Property and equipment, net	137.2	131.1
Equity Method Investments	86.7
Goodwill	2,217.6	2,220.3
Other intangible assets, net	1,168.8	1,328.0
Deferred financing costs, net	33.0	30.1
Other assets	3.2	1.6
Investments in and advances to subsidiaries	0	0
Total assets	6,099.9	5,924.6
Accounts payable-trade	704.0	662.8
Accounts payable-inventory financing	332.1	256.6
Current maturities of long-term debt	15.4	45.4
Deferred revenue	81.3	94.8
Accrued expenses	335.2	343.0
Total current liabilities	1,468.0	1,402.6
Debt	3,174.6	3,205.8
Deferred income taxes	475.0	563.5
Other liabilities	45.8	41.0
Total long-term liabilities	3,695.4	3,810.3
Total shareholders' (deficit) equity	936.5	711.7
Total liabilities and shareholders' (deficit) equity	$ 6,099.9	$ 5,924.6

Accounts payable inventory financing.

No definition available.

Name:	cdw_AccountsPayableInventoryFinancing
Namespace Prefix:	cdw_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Carrying value as of the balance sheet date of obligations incurred (and for which invoices have typically been received) and payable to vendors for goods and services received that are used in an entity's business. Used to reflect the current portion of the liabilities (due within one year or within the normal operating cycle if longer).

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 19

-Subparagraph a

-Article 5

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Glossary Current Liabilities

-URI http://asc.fasb.org/extlink&oid=6509677

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 10

-Section 45

-Paragraph 8

-URI http://asc.fasb.org/extlink&oid=28358313&loc=d3e6935-107765

Reference 4: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.5-02.19(a))

-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

+ Details

Name:	us-gaap_AccountsPayableTradeCurrent
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount due from customers or clients, within one year of the balance sheet date (or the normal operating cycle, whichever is longer), for goods or services (including trade receivables) that have been delivered or sold in the normal course of business, reduced to the estimated net realizable fair value by an allowance established by the entity of the amount it deems uncertain of collection.

+ References

+ Details

Name:	us-gaap_AccountsReceivableNetCurrent
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Carrying value as of the balance sheet date of obligations incurred and payable, pertaining to costs that are statutory in nature, are incurred on contractual obligations, or accumulate over time and for which invoices have not yet been received or will not be rendered. Examples include taxes, interest, rent and utilities. Used to reflect the current portion of the liabilities (due within one year or within the normal operating cycle if longer).

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 20

-Article 5

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.5-02.20)

-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

+ Details

Name:	us-gaap_AccruedLiabilitiesCurrent
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Sum of the carrying amounts as of the balance sheet date of all assets that are recognized. Assets are probable future economic benefits obtained or controlled by an entity as a result of past transactions or events.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.5-02.18)

-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 10

-Section S99

-Paragraph 1

-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 03

-Paragraph 12

-Article 7

Reference 4: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 18

-Article 5

+ Details

Name:	us-gaap_Assets
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Sum of the carrying amounts as of the balance sheet date of all assets that are expected to be realized in cash, sold, or consumed within one year (or the normal operating cycle, if longer). Assets are probable future economic benefits obtained or controlled by an entity as a result of past transactions or events.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.5-02.9)

-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 10

-Section 45

-Paragraph 3

-URI http://asc.fasb.org/extlink&oid=28358313&loc=d3e6801-107765

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 10

-Section 45

-Paragraph 1

-URI http://asc.fasb.org/extlink&oid=28358313&loc=d3e6676-107765

Reference 4: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 9

-Article 5

+ Details

Name:	us-gaap_AssetsCurrent
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Amount of currency on hand as well as demand deposits with banks or financial institutions. Includes other kinds of accounts that have the general characteristics of demand deposits. Also includes short-term, highly liquid investments that are both readily convertible to known amounts of cash and so near their maturity that they present insignificant risk of changes in value because of changes in interest rates. Excludes cash and cash equivalents within disposal group and discontinued operation.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Glossary Cash

-URI http://asc.fasb.org/extlink&oid=6506951

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Glossary Cash Equivalents

-URI http://asc.fasb.org/extlink&oid=6507016

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 1

-Article 5

Reference 4: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.5-02.1)

-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 5: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 10

-Section 45

-Paragraph 1

-Subparagraph (a)

-URI http://asc.fasb.org/extlink&oid=28358313&loc=d3e6676-107765

Reference 6: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 230

-SubTopic 10

-Section 45

-Paragraph 4

-URI http://asc.fasb.org/extlink&oid=31042434&loc=d3e3044-108585

+ Details

Name:	us-gaap_CashAndCashEquivalentsAtCarryingValue
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Details

Name:	us-gaap_CondensedFinancialStatementsCaptionsLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Net amount of long-term deferred finance costs capitalized at the end of the reporting period.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 835

-SubTopic 30

-Section 45

-Paragraph 3

-URI http://asc.fasb.org/extlink&oid=6451184&loc=d3e28555-108399

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.5-02.17)

-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 17

-Article 5

+ Details

Name:	us-gaap_DeferredFinanceCostsNoncurrentNet
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

The carrying amount of consideration received or receivable as of the balance sheet date on potential earnings that were not recognized as revenue in conformity with GAAP, and which are expected to be recognized as such within one year or the normal operating cycle, if longer, including sales, license fees, and royalties, but excluding interest income.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 605

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SAB TOPIC 13.A.4(a).Q1)

-URI http://asc.fasb.org/extlink&oid=27012821&loc=d3e214044-122780

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 10

-Section 45

-Paragraph 8

-Subparagraph (b)

-URI http://asc.fasb.org/extlink&oid=28358313&loc=d3e6935-107765

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Staff Accounting Bulletin (SAB)

-Number Topic 13

-Section A

+ Details

Name:	us-gaap_DeferredRevenueCurrent
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount of deferred tax liability attributable to taxable temporary differences, net of deferred tax asset attributable to deductible temporary differences and carryforwards net of valuation allowances expected to be realized or consumed after one year (or the normal operating cycle, if longer).

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 740

-SubTopic 10

-Section 45

-Paragraph 4

-URI http://asc.fasb.org/extlink&oid=37586315&loc=d3e31917-109318

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 740

-SubTopic 10

-Section 45

-Paragraph 6

-URI http://asc.fasb.org/extlink&oid=37586315&loc=d3e31931-109318

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 740

-SubTopic 10

-Section 45

-Paragraph 9

-URI http://asc.fasb.org/extlink&oid=37586315&loc=d3e31958-109318

+ Details

Name:	us-gaap_DeferredTaxLiabilitiesNoncurrent
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

This item represents the carrying amount on the entity's balance sheet of its investment in common stock of an equity method investee. This is not an indicator of the fair value of the investment, rather it is the initial cost adjusted for the entity's share of earnings and losses of the investee, adjusted for any distributions (dividends) and other than temporary impairment (OTTI) losses recognized.

+ References

+ Details

Name:	us-gaap_EquityMethodInvestments
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Amount after accumulated impairment loss of an asset representing future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 350

-SubTopic 20

-Section 50

-Paragraph 1

-URI http://asc.fasb.org/extlink&oid=35741047&loc=d3e13816-109267

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 350

-SubTopic 20

-Section 45

-Paragraph 1

-URI http://asc.fasb.org/extlink&oid=6388280&loc=d3e13770-109266

+ Details

Name:	us-gaap_Goodwill
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Sum of the carrying amounts of all intangible assets, excluding goodwill, as of the balance sheet date, net of accumulated amortization and impairment charges.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 350

-SubTopic 30

-Section 45

-Paragraph 1

-URI http://asc.fasb.org/extlink&oid=6388964&loc=d3e16212-109274

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 350

-SubTopic 30

-Section 50

-Paragraph 2

-Subparagraph ((a)(1),(b))

-URI http://asc.fasb.org/extlink&oid=26713463&loc=d3e16323-109275

+ Details

Name:	us-gaap_IntangibleAssetsNetExcludingGoodwill
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Amount after valuation and LIFO reserves of inventory expected to be sold, or consumed within one year or operating cycle, if longer.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.5-02.6(a))

-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 330

-SubTopic 10

-Section 35

-Paragraph 2

-URI http://asc.fasb.org/extlink&oid=6386567&loc=d3e3927-108312

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 10

-Section 45

-Paragraph 1

-Subparagraph (b)

-URI http://asc.fasb.org/extlink&oid=28358313&loc=d3e6676-107765

+ Details

Name:	us-gaap_InventoryNet
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Total investments in (A) an entity in which the entity has significant influence, but does not have control, (B) subsidiaries that are not required to be consolidated and are accounted for using the equity and or cost method, and (C) an entity in which the reporting entity shares control of the entity with another party or group. Includes long-term advances receivable from a party that is affiliated with the reporting entity by means of direct or indirect ownership.

+ References

+ Details

Name:	us-gaap_InvestmentsInAffiliatesSubsidiariesAssociatesAndJointVentures
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Amount of liabilities and equity items, including the portion of equity attributable to noncontrolling interests, if any.

+ References

+ Details

Name:	us-gaap_LiabilitiesAndStockholdersEquity
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Total obligations incurred as part of normal operations that are expected to be paid during the following twelve months or within one business cycle, if longer.

+ References

+ Details

Name:	us-gaap_LiabilitiesCurrent
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount of obligation due after one year or beyond the normal operating cycle, if longer.

+ References

+ Details

Name:	us-gaap_LiabilitiesNoncurrent
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount of long-term debt, after unamortized discount or premium, scheduled to be repaid within one year or the normal operating cycle, if longer. Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations.

+ References

+ Details

Name:	us-gaap_LongTermDebtCurrent
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Carrying amount of long-term debt, net of unamortized discount or premium, excluding amounts to be repaid within one year or the normal operating cycle, if longer (current maturities). Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations.

+ References

+ Details

Name:	us-gaap_LongTermDebtNoncurrent
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Aggregate carrying amount, as of the balance sheet date, of noncurrent assets not separately disclosed in the balance sheet. Noncurrent assets are expected to be realized or consumed after one year (or the normal operating cycle, if longer).

+ References

+ Details

Name:	us-gaap_OtherAssetsNoncurrent
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Aggregate carrying amount, as of the balance sheet date, of noncurrent obligations not separately disclosed in the balance sheet. Noncurrent liabilities are expected to be paid after one year (or the normal operating cycle, if longer).

+ References

+ Details

Name:	us-gaap_OtherLiabilitiesNoncurrent
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

The carrying amount of other receivables, net, due within one year of the balance sheet date (or one operating cycle, if longer) from third parties or arising from transactions not separately disclosed.

+ References

No definition available.

+ Details

Name:	us-gaap_OtherReceivablesNetCurrent
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Amount of asset related to consideration paid in advance for costs that provide economic benefits in future periods, and amount of other assets that are expected to be realized or consumed within one year or the normal operating cycle, if longer.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 8

-Article 5

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 10

-Section 45

-Paragraph 1

-URI http://asc.fasb.org/extlink&oid=28358313&loc=d3e6676-107765

+ Details

Name:	us-gaap_PrepaidExpenseAndOtherAssetsCurrent
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Amount after accumulated depreciation, depletion and amortization of physical assets used in the normal conduct of business to produce goods and services and not intended for resale. Examples include, but are not limited to, land, buildings, machinery and equipment, office equipment, and furniture and fixtures.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 360

-SubTopic 10

-Section 50

-Paragraph 1

-URI http://asc.fasb.org/extlink&oid=6391035&loc=d3e2868-110229

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.5-02.13)

-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 13

-Subparagraph a

-Article 5

Reference 4: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 03

-Paragraph 8

-Article 7

+ Details

Name:	us-gaap_PropertyPlantAndEquipmentNet
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Total of all stockholders' equity (deficit) items, net of receivables from officers, directors, owners, and affiliates of the entity which are attributable to the parent. The amount of the economic entity's stockholders' equity attributable to the parent excludes the amount of stockholders' equity which is allocable to that ownership interest in subsidiary equity which is not attributable to the parent (noncontrolling interest, minority interest). This excludes temporary equity and is sometimes called permanent equity.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 310

-SubTopic 10

-Section S99

-Paragraph 2

-Subparagraph (SAB TOPIC 4.E)

-URI http://asc.fasb.org/extlink&oid=27010918&loc=d3e74512-122707

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Staff Accounting Bulletin (SAB)

-Number Topic 4

-Section E

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.5-02.29-31)

-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 4: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 29, 30, 31

-Article 5

+ Details

Name:	us-gaap_StockholdersEquity
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Details

Name:	dei_LegalEntityAxis=cdw_CoIssuerMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	dei_LegalEntityAxis=us-gaap_ConsolidatedEntitiesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	dei_LegalEntityAxis=us-gaap_ConsolidationEliminationsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	dei_LegalEntityAxis=us-gaap_GuarantorSubsidiariesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	dei_LegalEntityAxis=us-gaap_NonGuarantorSubsidiariesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	dei_LegalEntityAxis=us-gaap_ParentCompanyMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	dei_LegalEntityAxis=us-gaap_SubsidiaryIssuerMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: