CDW (CDW) 10-Q 6 May 20 2020 Q1 Quarterly report Financial data

Cover Page

Cover Page - shares	3 Months Ended
	Mar. 31, 2020	May 01, 2020
Cover [Abstract]
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Mar. 31, 2020
Document Transition Report	false
Entity File Number	001-35985
Entity Central Index Key	0001402057
Current Fiscal Year End Date	--12-31
Entity Registrant Name	CDW CORP
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	26-0273989
Entity Address, Address Line One	75 Tri-State International
Entity Address, City or Town	Lincolnshire
Entity Address, State or Province	IL
Entity Address, Postal Zip Code	60069
City Area Code	847
Local Phone Number	465-6000
Title of 12(b) Security	Common stock, par value $0.01 per share
Trading Symbol	CDW
Security Exchange Name	NASDAQ
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Large Accelerated Filer
Entity Emerging Growth Company	false
Entity Small Business	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		142,318,092
Document Fiscal Year Focus	2020
Document Fiscal Period Focus	Q1
Amendment Flag	false

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Millions	Mar. 31, 2020	Dec. 31, 2019
Current assets:
Cash and cash equivalents	$ 214.4	$ 154
Accounts receivable, net of allowance for credit losses of $35.1 and $7.9, respectively	3,149.4	3,002.2
Merchandise inventory	672.1	611.2
Miscellaneous receivables	442.5	395.1
Prepaid expenses and other	187.4	171.6
Total current assets	4,665.8	4,334.1
Operating lease right-of-use assets	129.5	131.8
Property and equipment, net	331.9	363.1
Goodwill	2,529.5	2,553
Other intangible assets, net	540.2	594.1
Other assets	25.5	23.3
Total Assets	8,222.4	7,999.4
Current liabilities:
Accounts payable-trade	1,967.1	1,835
Accounts payable-inventory financing	345.5	429.9
Current maturities of long-term debt	33.7	34.1
Contract liabilities	257.6	252.2
Accrued expenses and other current liabilities:
Compensation	201.3	212.3
Advertising	158.6	147.9
Sales and income taxes	135.4	88.6
Other	548	491.4
Total current liabilities	3,647.2	3,491.4
Long-term liabilities:
Debt	3,438.5	3,283.2
Deferred income taxes	62.8	62.4
Operating lease liabilities	129.2	131.1
Other liabilities	55	71
Total long-term liabilities	3,685.5	3,547.7
Stockholders' equity:
Preferred stock, $0.01 par value, 100.0 shares authorized; no shares issued or outstanding for both periods	0	0
Common stock, $0.01 par value, 1,000.0 shares authorized; 142.3 and 143.0 shares outstanding, respectively	1.4	1.4
Paid-in capital	3,114.9	3,095.3
Accumulated deficit	(2,067.3)	(2,018.6)
Accumulated other comprehensive loss	(159.3)	(117.8)
Total stockholders' equity	889.7	960.3
Total Liabilities and Stockholders' Equity	$ 8,222.4	$ 7,999.4

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parentheticals) - USD ($) $ in Millions	Mar. 31, 2020	Dec. 31, 2019
Statement of Financial Position [Abstract]
Allowance for doubtful accounts	$ 35.1	$ 7.9
Preferred stock, par value (in dollars per share)	$ 0.01	$ 0.01
Preferred stock, authorized (in shares)	100,000,000	100,000,000
Preferred stock, issued (in shares)	0	0
Preferred stock, outstanding (in shares)	0	0
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01
Common stock, shares authorized (in shares)	1,000,000,000	1,000,000,000
Common stock, shares issued (in shares)	142,300,000	143,000,000
Common stock, shares outstanding (in shares)	142,300,000	143,000,000

Consolidated Statements Of Oper

Consolidated Statements Of Operations (Unaudited) - USD ($) shares in Millions, $ in Millions	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Income Statement [Abstract]
Net sales	$ 4,389.2	$ 3,957.9
Cost of sales	3,632.7	3,285.8
Gross profit	756.5	672.1
Selling and administrative expenses	510.7	443.2
Operating income	245.8	228.9
Interest expense, net	(37.9)	(38.3)
Other income, net	3.9	1
Income before income taxes	211.8	191.6
Income tax expense	(43.9)	(38.7)
Net income	$ 167.9	$ 152.9
Net income per common share:
Basic (in dollars per share)	$ 1.18	$ 1.04
Diluted (in dollars per share)	$ 1.16	$ 1.02
Weighted-average common shares outstanding:
Basic (in shares)	142.7	147
Diluted (in shares)	144.9	149.2

Consolidated Statements Of Comp

Consolidated Statements Of Comprehensive Income (Unaudited) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Statement of Comprehensive Income [Abstract]
Net income	$ 167.9	$ 152.9
Other comprehensive (loss) income:
Unrealized loss from hedge accounting, net of tax	(0.2)	(8.3)
Reclassification of hedge accounting gain to net income, net of tax	1.1	1.5
Foreign currency translation, net of tax	(42.4)	9.9
Other comprehensive (loss) income	(41.5)	3.1
Comprehensive income	$ 126.4	$ 156

Consolidated Statement of Share

Consolidated Statement of Shareholders' Equity (Unaudited) - USD ($) shares in Millions, $ in Millions	Total	Common Stock	Paid-in Capital	Accumulated Deficit	Accumulated Other Comprehensive Loss	Cumulative Effect, Period of Adoption, Adjustment	Cumulative Effect, Period of Adoption, AdjustmentAccumulated Deficit
Beginning balance (in shares) at Dec. 31, 2018		147.7
Beginning balance at Dec. 31, 2018	$ 975.2	$ 1.5	$ 2,996.9	$ (1,892.6)	$ (130.6)
Shareholders' Equity (Deficit) [Roll Forward]
Net income	152.9			152.9
Equity-based compensation expense	12.2		12.2
Stock option exercises (in shares)		0.5
Stock option exercises	13		13
Coworker stock purchase plan	3		3
Repurchases of common stock (in shares)		(1.9)
Repurchases of common stock	(177.1)	$ 0		(177.1)
Dividends paid	(43.4)		0.2	(43.6)
Incentive compensation plan stock withheld for taxes	(11.6)			(11.6)
Foreign currency translation	9.9				9.9
Unrealized (loss) gain from hedge accounting	(8.3)				(8.3)
Realized gain from hedge accounting	(1.5)				1.5
Ending balance (in shares) at Mar. 31, 2019		146.3
Ending balance at Mar. 31, 2019	927.3	$ 1.5	3,025.3	(1,972)	(127.5)
Beginning balance (in shares) at Dec. 31, 2019		143
Beginning balance at Dec. 31, 2019	960.3	$ 1.4	3,095.3	(2,018.6)	(117.8)	$ 0.5	$ 0.5
Shareholders' Equity (Deficit) [Roll Forward]
Net income	167.9			167.9
Equity-based compensation expense	8.8		8.8
Stock option exercises (in shares)		0.4
Stock option exercises	7.1		7.1
Coworker stock purchase plan	3.5		3.5
Repurchases of common stock (in shares)		(1.1)
Repurchases of common stock	(140.8)	$ 0		(140.8)
Dividends paid	(54.2)		0.2	(54.4)
Incentive compensation plan stock withheld for taxes	(21.9)			(21.9)
Foreign currency translation	(42.4)				(42.4)
Unrealized (loss) gain from hedge accounting	(0.2)				(0.2)
Realized gain from hedge accounting	(1.1)				1.1
Ending balance (in shares) at Mar. 31, 2020		142.3
Ending balance at Mar. 31, 2020	$ 889.7	$ 1.4	$ 3,114.9	$ (2,067.3)	$ (159.3)

Consolidated Statements of Shar

Consolidated Statements of Shareholders' Equity (Unaudited) (Parenthetical) - $ / shares	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Statement of Stockholders' Equity [Abstract]
Dividends (in dollars per share)	$ 0.38	$ 0.295

Consolidated Statements of Cash

Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Cash flows from operating activities:
Net income	$ 167.9	$ 152.9
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	91.4	64.3
Equity-based compensation expense	8.8	12.7
Deferred income taxes	2.6	(13.7)
Provision for credit losses	29.2	0.5
Other	1.4	2.3
Changes in assets and liabilities:
Accounts receivable	(209)	11.9
Merchandise inventory	(66.4)	(134.2)
Other assets	(63.7)	(31.9)
Accounts payable-trade	157.4	116
Other liabilities	103.4	71.6
Net cash provided by operating activities	223	252.4
Cash flows used in investing activities:
Capital expenditures	(25.4)	(19.4)
Acquisition of business, net of cash acquired	0	(68.7)
Net cash used in investing activities	(25.4)	(88.1)
Cash flows used in financing activities:
Proceeds from borrowings under revolving credit facility	781	88.5
Repayments of borrowings under revolving credit facility	(619.5)	(12.5)
Net change in accounts payable-inventory financing	(81.4)	70.2
Repurchases of common stock	(140.8)	(177.1)
Payment of incentive compensation plan withholding taxes	(21.9)	(11.6)
Dividend payments	(54.2)	(43.4)
Other	6.8	5.7
Net cash used in financing activities	(130)	(80.2)
Effect of exchange rate changes on cash, cash equivalents and restricted cash	(7.2)	0.8
Net increase in cash, cash equivalents and restricted cash	60.4	84.9
Cash, cash equivalents and restricted cash—beginning of period	154	205.8
Cash, cash equivalents and restricted cash—end of period	214.4	290.7
Supplementary disclosure of cash flow information:
Interest paid	(28.6)	(44.1)
Taxes paid, net	$ (9.9)	$ (11.4)

Description of Business and Sum

Description of Business and Summary of Significant Accounting Policies	3 Months Ended
	Mar. 31, 2020
Accounting Policies [Abstract]
Description of Business and Summary of Significant Accounting Policies	Description of Business and Summary of Significant Accounting Policies Description of Business CDW Corporation ("Parent"), a Fortune 500 company and member of the S&P 500 Index, is a market-leading provider of integrated information technology ("IT") solutions to small, medium and large business, government, education and healthcare customers in the United States ("US"), the United Kingdom ("UK") and Canada. The Company's offerings range from discrete hardware and software products to integrated IT solutions such as mobility, security, data center optimization, cloud computing, virtualization and collaboration. Throughout this report, the terms the "Company" and "CDW" refer to Parent and its 100% owned subsidiaries. Parent has two 100% owned subsidiaries, CDW LLC and CDW Finance Corporation. CDW LLC is an Illinois limited liability company that, together with its 100% owned subsidiaries, holds all material assets and conducts all business activities and operations of the Company. CDW Finance Corporation is a Delaware corporation formed for the sole purpose of acting as co-issuer of certain debt obligations and does not hold any material assets or engage in any business activities or operations. Basis of Presentation The accompanying unaudited interim Consolidated Financial Statements as of March 31, 2020 and for the three months ended March 31, 2020 and 2019 (the "Consolidated Financial Statements") have been prepared in conformity with accounting principles generally accepted in the United States of America ("GAAP") and the rules and regulations of the US Securities and Exchange Commission (the "SEC") for interim financial statements. Accordingly, certain information and footnote disclosures normally included in financial statements prepared in accordance with GAAP have been condensed or omitted pursuant to the rules and regulations of the SEC. These Consolidated Financial Statements should be read in conjunction with the audited Consolidated Financial Statements and the notes thereto included in the Company's Annual Report on Form 10-K for the year ended December 31, 2019 (the " December 31, 2019 Consolidated Financial Statements"). The significant accounting policies used in preparing these Consolidated Financial Statements were applied on a basis consistent with those reflected in the December 31, 2019 Consolidated Financial Statements. In the opinion of management, the Consolidated Financial Statements contain all adjustments (consisting of a normal, recurring nature) necessary to present fairly the Company's financial position, results of operations, comprehensive income, cash flows and changes in stockholders' equity as of the dates and for the periods indicated. The unaudited results of operations for such interim periods reported are not necessarily indicative of results for the full year. Reclassifications Certain prior period amounts have been reclassified to conform with current period presentation. Principles of Consolidation The Consolidated Financial Statements include the accounts of Parent and its 100% owned subsidiaries. All intercompany transactions and accounts are eliminated in consolidation. Use of Estimates The preparation of the Consolidated Financial Statements in accordance with GAAP requires management to make certain estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities as of the date of the Consolidated Financial Statements and the reported amounts of revenue and expenses during the reported periods. The Company bases its estimates on historical experience and on various other assumptions that management believes are reasonable under the circumstances, the results of which form the basis for making judgments about carrying values of assets and liabilities that are not readily apparent from other sources. Actual results and outcomes could differ from those estimates. The notes to the Consolidated Financial Statements contained in the December 31, 2019 Consolidated Financial Statements include a discussion of the Company's significant accounting policies and estimates. Except as noted within Note 2 (Recent Accounting Pronouncements) for the adoption of Accounting Standards Update ("ASU") 2016-13, Financial Instruments - Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments ("Topic 326"), there have been no changes to the Company's significant accounting policies and estimates during the three months ended March 31, 2020 . Accounts Receivable The Company estimates an allowance for credit losses related to accounts receivable for future expected credit losses by using relevant information such as historical information, current conditions, and reasonable and supportable forecasts. The allowance is measured on a pool basis when similar risk characteristics exist, and a loss-rate for each pool is determined using historical credit loss experience as the basis for the estimation of expected credit losses. Adjustments to historical loss information are made for differences in current conditions as well as changes in forecasted macroeconomic conditions, such as changes in unemployment rate or gross domestic product growth. Cash, Cash Equivalents and Restricted Cash Restricted cash represents funds that are restricted to satisfy designated current liabilities. The following table provides a reconciliation of cash, cash equivalents and restricted cash reported within the Consolidated Balance Sheets that sum to the total of the same amounts in the Consolidated Statements of Cash Flows. March 31, 2020 December 31, 2019 March 31, 2019 December 31, 2018 Cash and cash equivalents $ 214.4 $ 154.0 $ 285.0 $ 205.8 Restricted cash: Prepaid expenses and other — — 5.7 — Total cash, cash equivalents and restricted cash shown in the Consolidated Statements of Cash Flows $ 214.4 $ 154.0 $ 290.7 $ 205.8 Advertising Advertising costs are generally charged to expense in the period incurred. During the three months ended March 31, 2020 and 2019 , the Company had advertising costs of $45 million and $39 million , respectively, recorded in Selling and administrative expenses in the Consolidated Statements of Operations.

Recent Accounting Pronouncement

Recent Accounting Pronouncements	3 Months Ended
	Mar. 31, 2020
New Accounting Pronouncements and Changes in Accounting Principles [Abstract]
Recent Accounting Pronouncements	Recent Accounting Pronouncements Reference Rate Reform In March 2020, the Financial Accounting Standards Board issued ASU 2020-04, Reference Rate Reform (Topic 848): Facilitation of the Effects of Reference Rate Reform on Financial Reporting. This ASU temporarily provides optional expedients and exceptions for applying existing guidance to contract modifications, hedging relationships and other transactions that are expected to be affected by reference rate reform. The ASU was effective upon its issuance and will remain in effect for all contract modifications and hedging relationships entered into through December 31, 2022. The Company elected the expedient for cash flow hedges to assert the probability of the hedged forecasted transaction under Topic 815: Derivatives and Hedging, regardless of any expected modification in terms related to reference rate reform. This election did not have an impact to the Company’s Consolidated Financial Statements. As the Company begins modifying contracts impacted by reference rate reform, the other optional expedients will be evaluated for impact on the Consolidated Financial Statements. Measurement of Credit Losses on Financial Instruments On January 1, 2020, the Company adopted and applied ASU 2016-13, Financial Instruments - Credit Losses (Topic 326) using the modified retrospective approach. Topic 326 introduced a forward-looking approach based on expected losses to estimate credit losses on certain types of financial instruments, including trade receivables, which is reflected in the Company’s policies. The adoption of Topic 326, as well as the adjustment to retained earnings for the cumulative effect, was not significant to the Company's Consolidated Financial Statements.

Inventory Financing Agreements

Inventory Financing Agreements	3 Months Ended
	Mar. 31, 2020
Inventory Financing Agreements [Abstract]
Inventory Financing Agreements	Inventory Financing Agreements The Company has entered into agreements with certain financial intermediaries to facilitate the purchase of inventory from various suppliers under certain terms and conditions, as described below. These amounts are classified separately as Accounts payable-inventory financing on the Consolidated Balance Sheets. The Company does not incur any interest expense associated with these agreements as balances are paid when they are due. Amounts included in Accounts payable-inventory financing are as follows: March 31, 2020 December 31, 2019 Revolving Loan inventory financing agreement (1) $ 303.8 $ 379.1 Other inventory financing agreements 41.7 50.8 Accounts payable-inventory financing $ 345.5 $ 429.9 (1) The senior secured asset-based revolving credit facility includes an inventory floorplan sub-facility that enables the Company to maintain an inventory financing agreement with a financial intermediary to facilitate the purchase of inventory from certain vendors on more favorable terms than offered directly by the vendors.

Contract Liabilities and Perfor

Contract Liabilities and Performance Obligations	3 Months Ended
	Mar. 31, 2020
Revenue from Contract with Customer [Abstract]
Contract Liabilities and Performance Obligations	Contract Liabilities and Performance Obligations The Company's contract liabilities consist of payments received from customers, or such consideration that is contractually due, in advance of providing the product or performing services. The Company's contract liabilities are reported in a net position on a contract-by-contract basis at the end of each reporting period. As of March 31, 2020 and December 31, 2019 , the contract liability balance was $258 million and $252 million , respectively. During the three months ended March 31, 2020 and 2019 , the Company recognized revenue of $123 million and $74 million , respectively, related to its contract liabilities. A contract's transaction price is allocated to each distinct performance obligation and recognized as revenue when, or as, the performance obligation is satisfied. The following table represents the total transaction price for the remaining performance obligations as of March 31, 2020 related to noncancelable contracts longer than 12 months in duration that is expected to be recognized over future periods. Within 1 Year Years 1-2 Years 2-3 Thereafter Remaining performance obligations $ 42.7 $ 20.6 $ 8.6 $ 0.5

Financial Instruments

Financial Instruments	3 Months Ended
	Mar. 31, 2020
Financial Instruments [Abstract]
Financial Instruments	Financial Instruments The Company's indebtedness creates interest rate risk on its variable-rate debt. The Company uses derivative financial instruments to manage its exposure to interest rate risk. The Company does not hold or issue derivative financial instruments for trading or speculative purposes. The Company has interest rate cap agreements that entitle it to payments from the counterparty of the amount, if any, by which three-month London Interbank Offered Rate ("LIBOR") exceeds the strike rates of the caps during the agreement period in exchange for an upfront premium. During 2020 , the Company did not enter into interest rate cap agreements. As of March 31, 2020 and December 31, 2019 , the Company had interest rate cap agreements with a fair value of less than $1 million which were classified within Other assets on the Consolidated Balance Sheets. The total notional value of the interest rate cap agreements was $2.8 billion as of March 31, 2020 and December 31, 2019 of which $1.4 billion mature at December 31, 2020 and December 31, 2022 , respectively. The fair values of the Company's interest rate cap agreements are classified as Level 2 in the fair value hierarchy. The valuation of the interest rate cap agreements is derived by using a discounted cash flow analysis on the expected cash receipts that would occur if variable interest rates rise above the strike rates of the caps. This analysis reflects the contractual terms of the interest rate cap agreements, including the period to maturity, and uses observable market-based inputs, including LIBOR curves and implied volatilities. The Company also incorporates insignificant credit valuation adjustments to appropriately reflect the respective counterparty's nonperformance risk in the fair value measurements. The counterparty credit spreads are based on publicly available credit information obtained from a third-party credit data provider. For additional information, see Note 6 (Long-Term Debt) . The interest rate cap agreements are designated as cash flow hedges. The changes in the fair value of derivatives that qualify as cash flow hedges are recorded in Accumulated other comprehensive loss and are subsequently reclassified into Interest expense in the period when the hedged forecasted transaction affects earnings. The Company recorded an insignificant loss and a $8 million loss, net of tax, into Accumulated other comprehensive loss for the three months ended March 31, 2020 and 2019 , respectively. During the three months ended March 31, 2020 and 2019 , the Company reclassified $1 million and $2 million , net of tax, respectively, from Accumulated other comprehensive loss to earnings within Interest expense, net on the Consolidated Statements of Operations. The Company expects to reclassify $7 million from Accumulated other comprehensive loss to earnings within Interest expense, net during the next 12 months.

Long-Term Debt

Long-Term Debt	3 Months Ended
	Mar. 31, 2020
Debt Disclosure [Abstract]
Long-Term Debt	Long-Term Debt As of March 31, 2020 As of December 31, 2019 Maturity Interest Rate Amount Interest Rate Amount Credit Facilities CDW UK revolving credit facility (1) July 2021 — % $ — — % $ — Senior secured asset-based revolving credit facility March 2022 2.62 % 212.5 5.00 % 51.0 Total credit facilities 212.5 51.0 Term Loans CDW UK term loan (1) August 2021 2.07 % 57.1 2.19 % 61.0 Senior secured term loan facility October 2026 2.74 % 1,434.5 3.55 % 1,438.3 Total term loans 1,491.6 1,499.3 Unsecured Senior Notes Senior notes due 2024 ("2024 Senior Notes") December 2024 5.50 % 575.0 5.50 % 575.0 Senior notes due 2025 ("2025 Senior Notes") September 2025 5.00 % 600.0 5.00 % 600.0 Senior notes due 2028 ("2028 Senior Notes") April 2028 4.25 % 600.0 4.25 % 600.0 Total unsecured senior notes 1,775.0 1,775.0 Other long-term obligations 12.8 12.6 Unamortized deferred financing fees (19.7 ) (20.6 ) Current maturities of long-term debt (33.7 ) (34.1 ) Total long-term debt $ 3,438.5 $ 3,283.2 (1) British pound-denominated debt facilities. As of March 31, 2020 , the Company is in compliance with the covenants under the various credit agreements and indentures. Credit Facilities The Company has a variable rate CDW UK revolving credit facility that is denominated in British pounds. As of March 31, 2020 , the Company could have borrowed up to an additional £50 million ( $62 million ) under the CDW UK revolving credit facility. The Company also has a variable rate senior secured asset-based revolving credit facility (the "Revolving Loan") that is denominated in US dollars. The Revolving Loan is used by the Company for borrowings, issuances of letters of credit and floorplan financing. As of March 31, 2020 , the Revolving Loan had less than $1 million of undrawn letters of credit, $301 million reserved for the floorplan sub-facility and a borrowing base of $1.9 billion , which is based on the amount of eligible inventory and accounts receivable balances as of February 29, 2020 . As of March 31, 2020 , the Company could have borrowed up to an additional $0.9 billion under the Revolving Loan. The Revolving Loan is collateralized by a first priority interest in inventory (excluding inventory to the extent collateralized under the inventory financing arrangements as described in Note 3 (Inventory Financing Agreements) ), deposits and accounts receivable, and by a second priority interest in substantially all other US assets. Term Loans The CDW UK term loan has a variable interest rate. The Company is required to make annual principal installments of £5 million ( $6 million ), with the remaining principal amount due at the maturity date. The CDW UK term loan agreement imposes restrictions on CDW UK's ability to transfer funds to the Company through the payment of dividends, repayment of intercompany loans, advances or subordinated debt that require, among other things, the maintenance of a minimum net leverage ratio. As of March 31, 2020 , the amount of restricted payment capacity under the CDW UK term loan was £204 million ( $253 million ). The senior secured term loan facility (the "Term Loan") has a variable interest rate, which has effectively been capped through the use of interest rate caps (see Note 5 (Financial Instruments) ). The interest rate disclosed in the table above represents the variable interest rates in effect for March 31, 2020 and December 31, 2019 , respectively. The Company is required to pay quarterly principal installments of $4 million with the remaining principal amount due at the maturity date. As of March 31, 2020 , the amount of CDW's restricted payment capacity under the Term Loan was $1.9 billion . The Term Loan is collateralized by a second priority interest in substantially all inventory (excluding inventory to the extent collateralized under the inventory financing arrangements as described in Note 3 (Inventory Financing Agreements) , deposits and accounts receivable, and by a first priority interest in substantially all other US assets. Unsecured Senior Notes The senior notes have fixed interest rates, for which interest is paid semi-annually. Fair Value The fair values of the Senior Notes were estimated using quoted market prices for identical liabilities that are traded in over-the-counter secondary markets that are not considered active. The fair value of the Term Loan was estimated using dealer quotes for identical liabilities in markets that are not considered active. The Senior Notes, Term Loan and CDW UK term loan are classified as Level 2 within the fair value hierarchy. The carrying value of the Revolving Loan and CDW UK revolving credit facility approximate fair value if there are outstanding borrowings. The approximate fair values and related carrying values of the Company's long-term debt, including current maturities and excluding unamortized discount and unamortized deferred financing fees, are as follows: March 31, 2020 December 31, 2019 Fair value $ 3,429.4 $ 3,447.5 Carrying value 3,491.9 3,337.9

Income Taxes

Income Taxes	3 Months Ended
	Mar. 31, 2020
Income Tax Disclosure [Abstract]
Income Taxes	Income Taxes On March 27, 2020, the Coronavirus Aid, Relief, and Economic Security Act ("CARES Act") was enacted into law. The primary impact to the Company’s financial statements as a result of the CARES Act will be the deferral of US corporate income tax payments from the second quarter of 2020 to July 2020 as well as the deferral of employer related payroll tax payments from the second, third and fourth quarters of 2020 with 50% to be paid in the fourth quarter of 2021 and the remaining 50% to be paid in the fourth quarter of 2022. Income tax expense was $44 million and $39 million for the three months ended March 31, 2020 and 2019 , respectively. The effective tax rate, expressed by calculating the income tax expense as a percentage of Income before income taxes, was 20.7% for the three months ended March 31, 2020 and differed from the US federal statutory rate of 21.0% primarily due to excess tax benefits on equity-based compensation, partially offset by state and local income taxes. The effective tax rate for the three months ended March 31, 2019 was 20.2% and differed from the US federal statutory rate of 21.0% primarily due to excess tax benefits on equity-based compensation and a discrete tax benefit related to CDW Canada’s acquisition of Scalar Decisions Inc., partially offset by state and local income taxes.

Earnings per Share

Earnings per Share	3 Months Ended
	Mar. 31, 2020
Earnings Per Share [Abstract]
Earnings per Share	Earnings Per Share The numerator for both basic and diluted earnings per share is Net income. The denominator for basic earnings per share is the weighted-average shares outstanding during the period. A reconciliation of basic weighted-average shares outstanding to diluted weighted-average shares outstanding is as follows: Three Months Ended March 31, 2020 2019 Basic weighted-average shares outstanding 142.7 147.0 Effect of dilutive securities (1) 2.2 2.2 Diluted weighted-average shares outstanding (2) 144.9 149.2 (1) The dilutive effect of outstanding stock options, restricted stock units, restricted stock, performance share units and Coworker Stock Purchase Plan units is reflected in the diluted weighted-average shares outstanding using the treasury stock method. (2) There were fewer than 0.1 million potential common shares excluded from diluted weighted-average shares outstanding for both the three months ended March 31, 2020 and 2019 as their inclusion would have had an anti-dilutive effect.

Commitments and Contingencies

Commitments and Contingencies	3 Months Ended
	Mar. 31, 2020
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	Commitments and Contingencies The Company is party to various legal proceedings that arise in the ordinary course of its business, which include commercial, intellectual property, employment, tort and other litigation matters. The Company is also subject to audit by federal, state, international, national, provincial and local authorities, and by various partners, group purchasing organizations and customers, including government agencies, relating to purchases and sales under various contracts. In addition, the Company is subject to indemnification claims under various contracts. From time to time, certain customers of the Company file voluntary petitions for reorganization or liquidation under the US bankruptcy laws or similar laws of the jurisdictions for the Company's business activities outside of the US. In such cases, certain pre-petition payments received by the Company could be considered preference items and subject to return to the bankruptcy administrator. As of March 31, 2020 , the Company does not believe that there is a reasonable possibility that any material loss exceeding the amounts already recognized for these proceedings and matters, if any, has been incurred. However, the ultimate resolutions of these proceedings and matters are inherently unpredictable. As such, the Company's consolidated financial statements could be adversely affected in any particular period by the unfavorable resolution of one or more of these proceedings or matters.

Segment Information

Segment Information	3 Months Ended
	Mar. 31, 2020
Segment Reporting [Abstract]
Segment Information	Segment Information The Company has three reportable segments: Corporate, which is comprised primarily of US private sector business customers with more than 250 employees, Small Business, which primarily serves US private sector business customers with up to 250 employees, and Public, which is comprised of government agencies and education and healthcare institutions in the US. The Company has two other operating segments: CDW UK and CDW Canada, both of which do not meet the reportable segment quantitative thresholds and, accordingly, are included in an all other category ("Other"). Headquarters function costs that are not allocated to the segments are included under the heading of "Headquarters" in the tables below. Information about the Company's segments is as follows: Corporate Small Business Public Other Headquarters Total Three Months Ended March 31, 2020 Net sales $ 1,911.0 $ 391.5 $ 1,525.3 $ 561.4 $ — $ 4,389.2 Operating income (loss) 127.4 27.3 112.4 14.7 (36.0 ) 245.8 Depreciation and amortization expense (22.3 ) (5.8 ) (37.7 ) (8.0 ) (17.6 ) (91.4 ) Three Months Ended March 31, 2019 Net sales $ 1,736.2 $ 355.6 $ 1,330.7 $ 535.4 $ — $ 3,957.9 Operating income (loss) 134.7 24.4 76.1 25.6 (31.9 ) 228.9 Depreciation and amortization expense (21.5 ) (5.6 ) (12.7 ) (7.4 ) (17.1 ) (64.3 ) Geographic Areas and Revenue Mix Three Months Ended March 31, 2020 Corporate Small Business Public Other Total Geography (1) United States $ 1,907.8 $ 391.5 $ 1,525.3 $ 6.2 $ 3,830.8 Rest of World 3.2 — — 555.2 558.4 Total Net sales 1,911.0 391.5 1,525.3 561.4 4,389.2 Major Product and Services Hardware 1,513.9 324.4 1,210.8 407.4 3,456.5 Software 276.0 53.5 239.7 97.1 666.3 Services 100.1 8.2 67.8 54.5 230.6 Other (2) 21.0 5.4 7.0 2.4 35.8 Total Net sales 1,911.0 391.5 1,525.3 561.4 4,389.2 Sales by Channel Corporate 1,911.0 — — — 1,911.0 Small Business — 391.5 — — 391.5 Government — — 568.5 — 568.5 Education — — 476.2 — 476.2 Healthcare — — 480.6 — 480.6 Other — — — 561.4 561.4 Total Net sales 1,911.0 391.5 1,525.3 561.4 4,389.2 Timing of Revenue Recognition Transferred at a point in time where CDW is principal 1,741.0 366.7 1,404.6 499.0 4,011.3 Transferred at a point in time where CDW is agent 107.6 22.0 52.3 13.2 195.1 Transferred over time where CDW is principal 62.4 2.8 68.4 49.2 182.8 Total Net sales $ 1,911.0 $ 391.5 $ 1,525.3 $ 561.4 $ 4,389.2 (1) Net sales by geography is generally based on the ship-to address with the exception of certain services that may be performed at, or on behalf of, multiple locations. Such service arrangements are categorized based on the bill-to address. (2) Includes items such as delivery charges to customers. Three Months Ended March 31, 2019 Corporate Small Business Public Other Total Geography (1) United States $ 1,732.9 $ 355.6 $ 1,330.7 $ 8.4 $ 3,427.6 Rest of World 3.3 — — 527.0 530.3 Total Net sales 1,736.2 355.6 1,330.7 535.4 3,957.9 Major Product and Services Hardware 1,384.7 295.1 1,063.3 403.2 3,146.3 Software 246.5 48.1 221.1 77.3 593.0 Services 88.0 7.0 42.1 51.9 189.0 Other (2) 17.0 5.4 4.2 3.0 29.6 Total Net sales 1,736.2 355.6 1,330.7 535.4 3,957.9 Sales by Channel Corporate 1,736.2 — — — 1,736.2 Small Business — 355.6 — — 355.6 Government — — 488.4 — 488.4 Education — — 400.4 — 400.4 Healthcare — — 441.9 — 441.9 Other — — — 535.4 535.4 Total Net sales 1,736.2 355.6 1,330.7 535.4 3,957.9 Timing of Revenue Recognition Transferred at a point in time where CDW is principal 1,581.8 335.2 1,243.3 474.9 3,635.2 Transferred at a point in time where CDW is agent 104.0 19.8 46.2 13.0 183.0 Transferred over time where CDW is principal 50.4 0.6 41.2 47.5 139.7 Total Net sales $ 1,736.2 $ 355.6 $ 1,330.7 $ 535.4 $ 3,957.9 (1) Net sales by geography is generally based on the ship-to address with the exception of certain services that may be performed at, or on behalf of, multiple locations. Such service arrangements are categorized based on the bill-to address. (2) Includes items such as delivery charges to customers. The following table presents Net sales by major category for the three months ended March 31, 2020 and 2019 . Categories are based upon internal classifications. Three Months Ended March 31, 2020 2019 Net Sales Percentage Net Sales Percentage Notebooks/Mobile Devices $ 1,111.0 25.3 % $ 916.1 23.1 % Netcomm Products 456.4 10.4 511.4 12.9 Desktops 384.3 8.8 297.0 7.5 Video 314.6 7.2 271.3 6.9 Enterprise and Data Storage (Including Drives) 240.5 5.5 293.3 7.4 Other Hardware 949.7 21.5 857.2 21.7 Total Hardware 3,456.5 78.7 3,146.3 79.5 Software (1) 666.3 15.2 593.0 15.0 Services (1) 230.6 5.3 189.0 4.8 Other (2) 35.8 0.8 29.6 0.7 Total Net sales $ 4,389.2 100.0 % $ 3,957.9 100.0 % (1) Certain software and services revenues are recorded on a net basis for accounting purposes. As a result, the category percentage of net revenues is not representative of the category percentage of gross profits. (2) Includes items such as delivery charges to customers.

Subsequent Events

Subsequent Events	3 Months Ended
	Mar. 31, 2020
Subsequent Events [Abstract]
Subsequent Events	Subsequent Events On April 21, 2020, CDW completed the issuance of $600 million aggregate principal amount of 4.125% Senior Notes due 2025 at par.

Description of Business and S_2

Description of Business and Summary of Significant Accounting Policies (Policies)	3 Months Ended
	Mar. 31, 2020
Accounting Policies [Abstract]
Description of Business	Description of Business CDW Corporation ("Parent"), a Fortune 500 company and member of the S&P 500 Index, is a market-leading provider of integrated information technology ("IT") solutions to small, medium and large business, government, education and healthcare customers in the United States ("US"), the United Kingdom ("UK") and Canada. The Company's offerings range from discrete hardware and software products to integrated IT solutions such as mobility, security, data center optimization, cloud computing, virtualization and collaboration. Throughout this report, the terms the "Company" and "CDW" refer to Parent and its 100% owned subsidiaries. Parent has two 100% owned subsidiaries, CDW LLC and CDW Finance Corporation. CDW LLC is an Illinois limited liability company that, together with its 100% owned subsidiaries, holds all material assets and conducts all business activities and operations of the Company. CDW Finance Corporation is a Delaware corporation formed for the sole purpose of acting as co-issuer of certain debt obligations and does not hold any material assets or engage in any business activities or operations.
Basis of Presentation	Basis of Presentation The accompanying unaudited interim Consolidated Financial Statements as of March 31, 2020 and for the three months ended March 31, 2020 and 2019 (the "Consolidated Financial Statements") have been prepared in conformity with accounting principles generally accepted in the United States of America ("GAAP") and the rules and regulations of the US Securities and Exchange Commission (the "SEC") for interim financial statements. Accordingly, certain information and footnote disclosures normally included in financial statements prepared in accordance with GAAP have been condensed or omitted pursuant to the rules and regulations of the SEC. These Consolidated Financial Statements should be read in conjunction with the audited Consolidated Financial Statements and the notes thereto included in the Company's Annual Report on Form 10-K for the year ended December 31, 2019 (the " December 31, 2019 Consolidated Financial Statements"). The significant accounting policies used in preparing these Consolidated Financial Statements were applied on a basis consistent with those reflected in the December 31, 2019 Consolidated Financial Statements. In the opinion of management, the Consolidated Financial Statements contain all adjustments (consisting of a normal, recurring nature) necessary to present fairly the Company's financial position, results of operations, comprehensive income, cash flows and changes in stockholders' equity as of the dates and for the periods indicated. The unaudited results of operations for such interim periods reported are not necessarily indicative of results for the full year.
Reclassification	Reclassifications Certain prior period amounts have been reclassified to conform with current period presentation.
Principles of Consolidation	Principles of Consolidation The Consolidated Financial Statements include the accounts of Parent and its 100% owned subsidiaries. All intercompany transactions and accounts are eliminated in consolidation.
Use of Estimates	Use of Estimates The preparation of the Consolidated Financial Statements in accordance with GAAP requires management to make certain estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities as of the date of the Consolidated Financial Statements and the reported amounts of revenue and expenses during the reported periods. The Company bases its estimates on historical experience and on various other assumptions that management believes are reasonable under the circumstances, the results of which form the basis for making judgments about carrying values of assets and liabilities that are not readily apparent from other sources. Actual results and outcomes could differ from those estimates.
Accounts Receivable	Accounts Receivable The Company estimates an allowance for credit losses related to accounts receivable for future expected credit losses by using relevant information such as historical information, current conditions, and reasonable and supportable forecasts. The allowance is measured on a pool basis when similar risk characteristics exist, and a loss-rate for each pool is determined using historical credit loss experience as the basis for the estimation of expected credit losses. Adjustments to historical loss information are made for differences in current conditions as well as changes in forecasted macroeconomic conditions, such as changes in unemployment rate or gross domestic product growth.
Cash, Cash Equivalents and Restricted Cash	Cash, Cash Equivalents and Restricted Cash
Advertising	Advertising
Recent Accounting Pronouncements	Reference Rate Reform In March 2020, the Financial Accounting Standards Board issued ASU 2020-04, Reference Rate Reform (Topic 848): Facilitation of the Effects of Reference Rate Reform on Financial Reporting. This ASU temporarily provides optional expedients and exceptions for applying existing guidance to contract modifications, hedging relationships and other transactions that are expected to be affected by reference rate reform. The ASU was effective upon its issuance and will remain in effect for all contract modifications and hedging relationships entered into through December 31, 2022. The Company elected the expedient for cash flow hedges to assert the probability of the hedged forecasted transaction under Topic 815: Derivatives and Hedging, regardless of any expected modification in terms related to reference rate reform. This election did not have an impact to the Company’s Consolidated Financial Statements. As the Company begins modifying contracts impacted by reference rate reform, the other optional expedients will be evaluated for impact on the Consolidated Financial Statements. Measurement of Credit Losses on Financial Instruments On January 1, 2020, the Company adopted and applied ASU 2016-13, Financial Instruments - Credit Losses (Topic 326) using the modified retrospective approach. Topic 326 introduced a forward-looking approach based on expected losses to estimate credit losses on certain types of financial instruments, including trade receivables, which is reflected in the Company’s policies. The adoption of Topic 326, as well as the adjustment to retained earnings for the cumulative effect, was not significant to the Company's Consolidated Financial Statements.

Description of Business and S_3

Description of Business and Summary of Significant Accounting Policies (Tables)	3 Months Ended
	Mar. 31, 2020
Accounting Policies [Abstract]
Schedule of Cash and Cash Equivalents	The following table provides a reconciliation of cash, cash equivalents and restricted cash reported within the Consolidated Balance Sheets that sum to the total of the same amounts in the Consolidated Statements of Cash Flows. March 31, 2020 December 31, 2019 March 31, 2019 December 31, 2018 Cash and cash equivalents $ 214.4 $ 154.0 $ 285.0 $ 205.8 Restricted cash: Prepaid expenses and other — — 5.7 — Total cash, cash equivalents and restricted cash shown in the Consolidated Statements of Cash Flows $ 214.4 $ 154.0 $ 290.7 $ 205.8
Restrictions on Cash and Cash Equivalents	The following table provides a reconciliation of cash, cash equivalents and restricted cash reported within the Consolidated Balance Sheets that sum to the total of the same amounts in the Consolidated Statements of Cash Flows. March 31, 2020 December 31, 2019 March 31, 2019 December 31, 2018 Cash and cash equivalents $ 214.4 $ 154.0 $ 285.0 $ 205.8 Restricted cash: Prepaid expenses and other — — 5.7 — Total cash, cash equivalents and restricted cash shown in the Consolidated Statements of Cash Flows $ 214.4 $ 154.0 $ 290.7 $ 205.8

Inventory Financing Agreements

Inventory Financing Agreements (Tables)	3 Months Ended
	Mar. 31, 2020
Inventory Financing Agreements [Abstract]
Inventory Financing Agreements	Amounts included in Accounts payable-inventory financing are as follows: March 31, 2020 December 31, 2019 Revolving Loan inventory financing agreement (1) $ 303.8 $ 379.1 Other inventory financing agreements 41.7 50.8 Accounts payable-inventory financing $ 345.5 $ 429.9 (1) The senior secured asset-based revolving credit facility includes an inventory floorplan sub-facility that enables the Company to maintain an inventory financing agreement with a financial intermediary to facilitate the purchase of inventory from certain vendors on more favorable terms than offered directly by the vendors.

Contract Liabilities and Perf_2

Contract Liabilities and Performance Obligations (Tables)	3 Months Ended
	Mar. 31, 2020
Revenue from Contract with Customer [Abstract]
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction	The following table represents the total transaction price for the remaining performance obligations as of March 31, 2020 related to noncancelable contracts longer than 12 months in duration that is expected to be recognized over future periods. Within 1 Year Years 1-2 Years 2-3 Thereafter Remaining performance obligations $ 42.7 $ 20.6 $ 8.6 $ 0.5

Long-Term Debt (Tables)

Long-Term Debt (Tables)	3 Months Ended
	Mar. 31, 2020
Debt Disclosure [Abstract]
Schedule of Long-term Debt Instruments	As of March 31, 2020 As of December 31, 2019 Maturity Interest Rate Amount Interest Rate Amount Credit Facilities CDW UK revolving credit facility (1) July 2021 — % $ — — % $ — Senior secured asset-based revolving credit facility March 2022 2.62 % 212.5 5.00 % 51.0 Total credit facilities 212.5 51.0 Term Loans CDW UK term loan (1) August 2021 2.07 % 57.1 2.19 % 61.0 Senior secured term loan facility October 2026 2.74 % 1,434.5 3.55 % 1,438.3 Total term loans 1,491.6 1,499.3 Unsecured Senior Notes Senior notes due 2024 ("2024 Senior Notes") December 2024 5.50 % 575.0 5.50 % 575.0 Senior notes due 2025 ("2025 Senior Notes") September 2025 5.00 % 600.0 5.00 % 600.0 Senior notes due 2028 ("2028 Senior Notes") April 2028 4.25 % 600.0 4.25 % 600.0 Total unsecured senior notes 1,775.0 1,775.0 Other long-term obligations 12.8 12.6 Unamortized deferred financing fees (19.7 ) (20.6 ) Current maturities of long-term debt (33.7 ) (34.1 ) Total long-term debt $ 3,438.5 $ 3,283.2 (1) British pound-denominated debt facilities.
Carrying Value of Long-Term Debt	The approximate fair values and related carrying values of the Company's long-term debt, including current maturities and excluding unamortized discount and unamortized deferred financing fees, are as follows: March 31, 2020 December 31, 2019 Fair value $ 3,429.4 $ 3,447.5 Carrying value 3,491.9 3,337.9

Earnings per Share (Tables)

Earnings per Share (Tables)	3 Months Ended
	Mar. 31, 2020
Earnings Per Share [Abstract]
Schedule of Weighted Average Number of Shares	A reconciliation of basic weighted-average shares outstanding to diluted weighted-average shares outstanding is as follows: Three Months Ended March 31, 2020 2019 Basic weighted-average shares outstanding 142.7 147.0 Effect of dilutive securities (1) 2.2 2.2 Diluted weighted-average shares outstanding (2) 144.9 149.2 (1) The dilutive effect of outstanding stock options, restricted stock units, restricted stock, performance share units and Coworker Stock Purchase Plan units is reflected in the diluted weighted-average shares outstanding using the treasury stock method. (2) There were fewer than 0.1 million potential common shares excluded from diluted weighted-average shares outstanding for both the three months ended March 31, 2020 and 2019 as their inclusion would have had an anti-dilutive effect.

Segment Information (Tables)

Segment Information (Tables)	3 Months Ended
	Mar. 31, 2020
Segment Reporting [Abstract]
Schedule of Segment Reporting Information, by Segment	Information about the Company's segments is as follows: Corporate Small Business Public Other Headquarters Total Three Months Ended March 31, 2020 Net sales $ 1,911.0 $ 391.5 $ 1,525.3 $ 561.4 $ — $ 4,389.2 Operating income (loss) 127.4 27.3 112.4 14.7 (36.0 ) 245.8 Depreciation and amortization expense (22.3 ) (5.8 ) (37.7 ) (8.0 ) (17.6 ) (91.4 ) Three Months Ended March 31, 2019 Net sales $ 1,736.2 $ 355.6 $ 1,330.7 $ 535.4 $ — $ 3,957.9 Operating income (loss) 134.7 24.4 76.1 25.6 (31.9 ) 228.9 Depreciation and amortization expense (21.5 ) (5.6 ) (12.7 ) (7.4 ) (17.1 ) (64.3 )
Disaggregation of Revenue	Geographic Areas and Revenue Mix Three Months Ended March 31, 2020 Corporate Small Business Public Other Total Geography (1) United States $ 1,907.8 $ 391.5 $ 1,525.3 $ 6.2 $ 3,830.8 Rest of World 3.2 — — 555.2 558.4 Total Net sales 1,911.0 391.5 1,525.3 561.4 4,389.2 Major Product and Services Hardware 1,513.9 324.4 1,210.8 407.4 3,456.5 Software 276.0 53.5 239.7 97.1 666.3 Services 100.1 8.2 67.8 54.5 230.6 Other (2) 21.0 5.4 7.0 2.4 35.8 Total Net sales 1,911.0 391.5 1,525.3 561.4 4,389.2 Sales by Channel Corporate 1,911.0 — — — 1,911.0 Small Business — 391.5 — — 391.5 Government — — 568.5 — 568.5 Education — — 476.2 — 476.2 Healthcare — — 480.6 — 480.6 Other — — — 561.4 561.4 Total Net sales 1,911.0 391.5 1,525.3 561.4 4,389.2 Timing of Revenue Recognition Transferred at a point in time where CDW is principal 1,741.0 366.7 1,404.6 499.0 4,011.3 Transferred at a point in time where CDW is agent 107.6 22.0 52.3 13.2 195.1 Transferred over time where CDW is principal 62.4 2.8 68.4 49.2 182.8 Total Net sales $ 1,911.0 $ 391.5 $ 1,525.3 $ 561.4 $ 4,389.2 (1) Net sales by geography is generally based on the ship-to address with the exception of certain services that may be performed at, or on behalf of, multiple locations. Such service arrangements are categorized based on the bill-to address. (2) Includes items such as delivery charges to customers. Three Months Ended March 31, 2019 Corporate Small Business Public Other Total Geography (1) United States $ 1,732.9 $ 355.6 $ 1,330.7 $ 8.4 $ 3,427.6 Rest of World 3.3 — — 527.0 530.3 Total Net sales 1,736.2 355.6 1,330.7 535.4 3,957.9 Major Product and Services Hardware 1,384.7 295.1 1,063.3 403.2 3,146.3 Software 246.5 48.1 221.1 77.3 593.0 Services 88.0 7.0 42.1 51.9 189.0 Other (2) 17.0 5.4 4.2 3.0 29.6 Total Net sales 1,736.2 355.6 1,330.7 535.4 3,957.9 Sales by Channel Corporate 1,736.2 — — — 1,736.2 Small Business — 355.6 — — 355.6 Government — — 488.4 — 488.4 Education — — 400.4 — 400.4 Healthcare — — 441.9 — 441.9 Other — — — 535.4 535.4 Total Net sales 1,736.2 355.6 1,330.7 535.4 3,957.9 Timing of Revenue Recognition Transferred at a point in time where CDW is principal 1,581.8 335.2 1,243.3 474.9 3,635.2 Transferred at a point in time where CDW is agent 104.0 19.8 46.2 13.0 183.0 Transferred over time where CDW is principal 50.4 0.6 41.2 47.5 139.7 Total Net sales $ 1,736.2 $ 355.6 $ 1,330.7 $ 535.4 $ 3,957.9 (1) Net sales by geography is generally based on the ship-to address with the exception of certain services that may be performed at, or on behalf of, multiple locations. Such service arrangements are categorized based on the bill-to address. (2) Includes items such as delivery charges to customers. The following table presents Net sales by major category for the three months ended March 31, 2020 and 2019 . Categories are based upon internal classifications. Three Months Ended March 31, 2020 2019 Net Sales Percentage Net Sales Percentage Notebooks/Mobile Devices $ 1,111.0 25.3 % $ 916.1 23.1 % Netcomm Products 456.4 10.4 511.4 12.9 Desktops 384.3 8.8 297.0 7.5 Video 314.6 7.2 271.3 6.9 Enterprise and Data Storage (Including Drives) 240.5 5.5 293.3 7.4 Other Hardware 949.7 21.5 857.2 21.7 Total Hardware 3,456.5 78.7 3,146.3 79.5 Software (1) 666.3 15.2 593.0 15.0 Services (1) 230.6 5.3 189.0 4.8 Other (2) 35.8 0.8 29.6 0.7 Total Net sales $ 4,389.2 100.0 % $ 3,957.9 100.0 % (1) Certain software and services revenues are recorded on a net basis for accounting purposes. As a result, the category percentage of net revenues is not representative of the category percentage of gross profits. (2) Includes items such as delivery charges to customers.

Description of Business and S_4

Description of Business and Summary of Significant Accounting Policies (Details) $ in Millions	3 Months Ended
	Mar. 31, 2020USD ($)subsidiary	Mar. 31, 2019USD ($)	Dec. 31, 2019USD ($)	Dec. 31, 2018USD ($)
Accounting Policies [Abstract]
Number of owned subsidiaries | subsidiary	2
Cash and cash equivalents	$ 214.4	$ 285	$ 154	$ 205.8
Restricted cash	0	5.7	0	0
Total cash, cash equivalents and restricted cash shown in the Consolidated Statements of Cash Flows	214.4	290.7	$ 154	$ 205.8
Advertising costs	$ 45	$ 39

Inventory Financing Agreement_2

Inventory Financing Agreements (Details) - USD ($) $ in Millions	Mar. 31, 2020	Dec. 31, 2019
Inventory Financing Agreements [Line Items]
Accounts payable-inventory financing	$ 345.5	$ 429.9
Accounts Payable, Inventory Financing
Inventory Financing Agreements [Line Items]
Revolving Loan inventory financing agreement	303.8	379.1
Other inventory financing agreements	$ 41.7	$ 50.8

Contract Liabilities and Perf_3

Contract Liabilities and Performance Obligations - Narrative (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019	Dec. 31, 2019
Revenue from Contract with Customer [Abstract]
Contract liabilities	$ 258		$ 252
Revenue recognized from contract with customer	$ (123)	$ 74

Contract Liabilities and Perf_4

Contract Liabilities and Performance Obligations - Schedule of Remaining Performance Obligations (Details) $ in Millions	Mar. 31, 2020USD ($)
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2020-04-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Remaining performance obligations, expected timing of satisfaction, period	1 year
Remaining performance obligations	$ 42.7
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2021-04-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Remaining performance obligations, expected timing of satisfaction, period	1 year
Remaining performance obligations	$ 20.6
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2022-04-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Remaining performance obligations, expected timing of satisfaction, period	1 year
Remaining performance obligations	$ 8.6
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2023-04-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Remaining performance obligations, expected timing of satisfaction, period
Remaining performance obligations	$ 0.5

Financial Instruments - Narrati

Financial Instruments - Narrative (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019	Dec. 31, 2019
Derivative [Line Items]
Interest rate cap, fair value	$ 1		$ 1
Unrealized (loss) gain from hedge accounting	(0.2)	$ (8.3)
Interest Rate Cap
Derivative [Line Items]
Notional amount	2,800		$ 2,800
Interest Rate Contract
Derivative [Line Items]
Unrealized (loss) gain from hedge accounting		(8)
Amount expected to be reclassified from AOCL to interest expense in next twelve months	7
Derivative
Derivative [Line Items]
Interest income (expense) reclassified into earnings	(1)	$ (2)
Cap agreement effective 12/31/20-12/31/22
Derivative [Line Items]
Notional amount	1,400
Cap agreement effective 12/31/18-12/31/20
Derivative [Line Items]
Notional amount	$ 1,400

Long-Term Debt - Debt Balances

Long-Term Debt - Debt Balances and Interest Rates (Details) - USD ($) $ in Millions	Mar. 31, 2020	Dec. 31, 2019
Debt Instrument [Line Items]
Long-term debt	$ 3,491.9	$ 3,337.9
Unamortized deferred financing fees	(19.7)	(20.6)
Current maturities of long-term debt	(33.7)	(34.1)
Total long-term debt	3,438.5	3,283.2
Total credit facilities
Debt Instrument [Line Items]
Long-term debt	$ 212.5	$ 51
CDW UK revolving credit facility
Debt Instrument [Line Items]
Interest rate in effect	0.00%	0.00%
Long-term debt	$ 0	$ 0
Senior secured asset-based revolving credit facility
Debt Instrument [Line Items]
Interest rate in effect	2.62%	5.00%
Long-term debt	$ 212.5	$ 51
Total term loans
Debt Instrument [Line Items]
Long-term debt	$ 1,491.6	$ 1,499.3
CDW UK term loan
Debt Instrument [Line Items]
Interest rate in effect	2.07%	2.19%
Long-term debt	$ 57.1	$ 61
Senior secured term loan facility
Debt Instrument [Line Items]
Interest rate in effect	2.74%	3.55%
Long-term debt	$ 1,434.5	$ 1,438.3
Total unsecured senior notes
Debt Instrument [Line Items]
Long-term debt	$ 1,775	$ 1,775
Senior notes due 2024
Debt Instrument [Line Items]
Interest rate in effect	5.50%	5.50%
Long-term debt	$ 575	$ 575
Senior notes due 2025
Debt Instrument [Line Items]
Interest rate in effect	5.00%	5.00%
Long-term debt	$ 600	$ 600
Senior Notes due 2028
Debt Instrument [Line Items]
Interest rate in effect	4.25%	4.25%
Long-term debt	$ 600	$ 600
Other long-term obligations
Debt Instrument [Line Items]
Long-term debt	$ 12.8	$ 12.6

Long-Term Debt - Narrative (Det

Long-Term Debt - Narrative (Details) - 3 months ended Mar. 31, 2020 $ in Millions	GBP (£)	USD ($)	USD ($)
CDW UK revolving credit facility
Debt Instrument [Line Items]
Borrowing capacity of the Revolving Loan	£ 50,000,000		$ 62
Senior secured asset-based revolving credit facility
Debt Instrument [Line Items]
Undrawn letters of credit			1
Borrowing base			1,900
Additional borrowing capacity			900
CDW UK term loan
Debt Instrument [Line Items]
Annual principal repayment installments	5,000,000	$ 6
Amount of restricted payment capacity under the loan	£ 204,000,000		253
Senior secured term loan facility
Debt Instrument [Line Items]
Amount of restricted payment capacity under the loan			1,900
Periodic payment, principal		$ 4
Accounts Payable, Inventory Financing | Senior secured asset-based revolving credit facility
Debt Instrument [Line Items]
Amount owed under Revolving loan financing agreement			$ 301

Long-Term Debt - Fair Value of

Long-Term Debt - Fair Value of Long-Term Debt (Details) - USD ($) $ in Millions	Mar. 31, 2020	Dec. 31, 2019
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Carrying value	$ 3,491.9	$ 3,337.9
Level 2
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair value	$ 3,429.4	$ 3,447.5

Income Taxes - Narrative (Detai

Income Taxes - Narrative (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Income Tax Disclosure [Abstract]
Income tax (expense) benefit	$ 43.9	$ 38.7
Effective income tax rate reconciliation, percent	20.70%	20.20%

Earnings per Share (Details)

Earnings per Share (Details) - shares shares in Millions	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Earnings Per Share [Abstract]
Basic weighted-average shares outstanding (in shares)	142.7	147
Effect of dilutive securities (in shares)	2.2	2.2
Diluted weighted-average shares outstanding (in shares)	144.9	149.2
Anti-dilutive shares (fewer than) (in shares)	0.1	0.1

Segment Information - Narrative

Segment Information - Narrative (Details)	3 Months Ended
	Mar. 31, 2020employeesegment
Segment Reporting Information [Line Items]
Number of reportable segments | segment	3
Number of operating segments which do not meet reportable unit quantitative threshold | segment	2
Minimum | Corporate
Segment Reporting Information [Line Items]
Customer segments, customer employee headcount | employee	250
Maximum | Small Business
Segment Reporting Information [Line Items]
Customer segments, customer employee headcount | employee	250

Segment Information - Schedule

Segment Information - Schedule of Segment Information (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Segment Reporting Information [Line Items]
Net sales	$ 4,389.2	$ 3,957.9
Income (loss) from operations	245.8	228.9
Depreciation and amortization expense	(91.4)	(64.3)
Operating Segments | Corporate
Segment Reporting Information [Line Items]
Net sales	1,911	1,736.2
Income (loss) from operations	127.4	134.7
Depreciation and amortization expense	(22.3)	(21.5)
Operating Segments | Small Business
Segment Reporting Information [Line Items]
Net sales	391.5	355.6
Income (loss) from operations	27.3	24.4
Depreciation and amortization expense	(5.8)	(5.6)
Operating Segments | Public
Segment Reporting Information [Line Items]
Net sales	1,525.3	1,330.7
Income (loss) from operations	112.4	76.1
Depreciation and amortization expense	(37.7)	(12.7)
Operating Segments | Other
Segment Reporting Information [Line Items]
Net sales	561.4	535.4
Income (loss) from operations	14.7	25.6
Depreciation and amortization expense	(8)	(7.4)
Headquarters
Segment Reporting Information [Line Items]
Net sales	0	0
Income (loss) from operations	(36)	(31.9)
Depreciation and amortization expense	$ (17.6)	$ (17.1)

Segment Information - Disaggreg

Segment Information - Disaggregation of Revenue (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Disaggregation of Revenue [Line Items]
Net sales	$ 4,389.2	$ 3,957.9
Percentage of Total Net Sales	100.00%	100.00%
Operating Segments | Corporate
Disaggregation of Revenue [Line Items]
Net sales	$ 1,911	$ 1,736.2
Operating Segments | Small Business
Disaggregation of Revenue [Line Items]
Net sales	391.5	355.6
Operating Segments | Public
Disaggregation of Revenue [Line Items]
Net sales	1,525.3	1,330.7
Operating Segments | Other
Disaggregation of Revenue [Line Items]
Net sales	561.4	535.4
Transferred at a point in time where CDW is principal
Disaggregation of Revenue [Line Items]
Net sales	4,011.3	3,635.2
Transferred at a point in time where CDW is principal | Operating Segments | Corporate
Disaggregation of Revenue [Line Items]
Net sales	1,741	1,581.8
Transferred at a point in time where CDW is principal | Operating Segments | Small Business
Disaggregation of Revenue [Line Items]
Net sales	366.7	335.2
Transferred at a point in time where CDW is principal | Operating Segments | Public
Disaggregation of Revenue [Line Items]
Net sales	1,404.6	1,243.3
Transferred at a point in time where CDW is principal | Operating Segments | Other
Disaggregation of Revenue [Line Items]
Net sales	499	474.9
Transferred at a point in time where CDW is agent
Disaggregation of Revenue [Line Items]
Net sales	195.1	183
Transferred at a point in time where CDW is agent | Operating Segments | Corporate
Disaggregation of Revenue [Line Items]
Net sales	107.6	104
Transferred at a point in time where CDW is agent | Operating Segments | Small Business
Disaggregation of Revenue [Line Items]
Net sales	22	19.8
Transferred at a point in time where CDW is agent | Operating Segments | Public
Disaggregation of Revenue [Line Items]
Net sales	52.3	46.2
Transferred at a point in time where CDW is agent | Operating Segments | Other
Disaggregation of Revenue [Line Items]
Net sales	13.2	13
Transferred over time where CDW is principal
Disaggregation of Revenue [Line Items]
Net sales	182.8	139.7
Transferred over time where CDW is principal | Operating Segments | Corporate
Disaggregation of Revenue [Line Items]
Net sales	62.4	50.4
Transferred over time where CDW is principal | Operating Segments | Small Business
Disaggregation of Revenue [Line Items]
Net sales	2.8	0.6
Transferred over time where CDW is principal | Operating Segments | Public
Disaggregation of Revenue [Line Items]
Net sales	68.4	41.2
Transferred over time where CDW is principal | Operating Segments | Other
Disaggregation of Revenue [Line Items]
Net sales	49.2	47.5
Corporate
Disaggregation of Revenue [Line Items]
Net sales	1,911	1,736.2
Corporate | Operating Segments | Corporate
Disaggregation of Revenue [Line Items]
Net sales	1,911	1,736.2
Corporate | Operating Segments | Small Business
Disaggregation of Revenue [Line Items]
Net sales	0	0
Corporate | Operating Segments | Public
Disaggregation of Revenue [Line Items]
Net sales	0	0
Corporate | Operating Segments | Other
Disaggregation of Revenue [Line Items]
Net sales	0	0
Small Business
Disaggregation of Revenue [Line Items]
Net sales	391.5	355.6
Small Business | Operating Segments | Corporate
Disaggregation of Revenue [Line Items]
Net sales	0	0
Small Business | Operating Segments | Small Business
Disaggregation of Revenue [Line Items]
Net sales	391.5	355.6
Small Business | Operating Segments | Public
Disaggregation of Revenue [Line Items]
Net sales	0	0
Small Business | Operating Segments | Other
Disaggregation of Revenue [Line Items]
Net sales	0	0
Government
Disaggregation of Revenue [Line Items]
Net sales	568.5	488.4
Government | Operating Segments | Corporate
Disaggregation of Revenue [Line Items]
Net sales	0	0
Government | Operating Segments | Small Business
Disaggregation of Revenue [Line Items]
Net sales	0	0
Government | Operating Segments | Public
Disaggregation of Revenue [Line Items]
Net sales	568.5	488.4
Government | Operating Segments | Other
Disaggregation of Revenue [Line Items]
Net sales	0	0
Education
Disaggregation of Revenue [Line Items]
Net sales	476.2	400.4
Education | Operating Segments | Corporate
Disaggregation of Revenue [Line Items]
Net sales	0	0
Education | Operating Segments | Small Business
Disaggregation of Revenue [Line Items]
Net sales	0	0
Education | Operating Segments | Public
Disaggregation of Revenue [Line Items]
Net sales	476.2	400.4
Education | Operating Segments | Other
Disaggregation of Revenue [Line Items]
Net sales	0	0
Healthcare
Disaggregation of Revenue [Line Items]
Net sales	480.6	441.9
Healthcare | Operating Segments | Corporate
Disaggregation of Revenue [Line Items]
Net sales	0	0
Healthcare | Operating Segments | Small Business
Disaggregation of Revenue [Line Items]
Net sales	0	0
Healthcare | Operating Segments | Public
Disaggregation of Revenue [Line Items]
Net sales	480.6	441.9
Healthcare | Operating Segments | Other
Disaggregation of Revenue [Line Items]
Net sales	0	0
Other
Disaggregation of Revenue [Line Items]
Net sales	561.4	535.4
Other | Operating Segments | Corporate
Disaggregation of Revenue [Line Items]
Net sales	0	0
Other | Operating Segments | Small Business
Disaggregation of Revenue [Line Items]
Net sales	0	0
Other | Operating Segments | Public
Disaggregation of Revenue [Line Items]
Net sales	0	0
Other | Operating Segments | Other
Disaggregation of Revenue [Line Items]
Net sales	561.4	535.4
Hardware
Disaggregation of Revenue [Line Items]
Net sales	$ 3,456.5	$ 3,146.3
Percentage of Total Net Sales	78.70%	79.50%
Hardware | Operating Segments | Corporate
Disaggregation of Revenue [Line Items]
Net sales	$ 1,513.9	$ 1,384.7
Hardware | Operating Segments | Small Business
Disaggregation of Revenue [Line Items]
Net sales	324.4	295.1
Hardware | Operating Segments | Public
Disaggregation of Revenue [Line Items]
Net sales	1,210.8	1,063.3
Hardware | Operating Segments | Other
Disaggregation of Revenue [Line Items]
Net sales	407.4	403.2
Notebooks/Mobile Devices
Disaggregation of Revenue [Line Items]
Net sales	$ 1,111	$ 916.1
Percentage of Total Net Sales	25.30%	23.10%
Netcomm Products
Disaggregation of Revenue [Line Items]
Net sales	$ 456.4	$ 511.4
Percentage of Total Net Sales	10.40%	12.90%
Desktops
Disaggregation of Revenue [Line Items]
Net sales	$ 384.3	$ 297
Percentage of Total Net Sales	8.80%	7.50%
Video
Disaggregation of Revenue [Line Items]
Net sales	$ 314.6	$ 271.3
Percentage of Total Net Sales	7.20%	6.90%
Enterprise and Data Storage (Including Drives)
Disaggregation of Revenue [Line Items]
Net sales	$ 240.5	$ 293.3
Percentage of Total Net Sales	5.50%	7.40%
Other Hardware
Disaggregation of Revenue [Line Items]
Net sales	$ 949.7	$ 857.2
Percentage of Total Net Sales	21.50%	21.70%
Software
Disaggregation of Revenue [Line Items]
Net sales	$ 666.3	$ 593
Percentage of Total Net Sales	15.20%	15.00%
Software | Operating Segments | Corporate
Disaggregation of Revenue [Line Items]
Net sales	$ 276	$ 246.5
Software | Operating Segments | Small Business
Disaggregation of Revenue [Line Items]
Net sales	53.5	48.1
Software | Operating Segments | Public
Disaggregation of Revenue [Line Items]
Net sales	239.7	221.1
Software | Operating Segments | Other
Disaggregation of Revenue [Line Items]
Net sales	97.1	77.3
Services
Disaggregation of Revenue [Line Items]
Net sales	$ 230.6	$ 189
Percentage of Total Net Sales	5.30%	4.80%
Services | Operating Segments | Corporate
Disaggregation of Revenue [Line Items]
Net sales	$ 100.1	$ 88
Services | Operating Segments | Small Business
Disaggregation of Revenue [Line Items]
Net sales	8.2	7
Services | Operating Segments | Public
Disaggregation of Revenue [Line Items]
Net sales	67.8	42.1
Services | Operating Segments | Other
Disaggregation of Revenue [Line Items]
Net sales	54.5	51.9
Other
Disaggregation of Revenue [Line Items]
Net sales	$ 35.8	$ 29.6
Percentage of Total Net Sales	0.80%	0.70%
Other | Operating Segments | Corporate
Disaggregation of Revenue [Line Items]
Net sales	$ 21	$ 17
Other | Operating Segments | Small Business
Disaggregation of Revenue [Line Items]
Net sales	5.4	5.4
Other | Operating Segments | Public
Disaggregation of Revenue [Line Items]
Net sales	7	4.2
Other | Operating Segments | Other
Disaggregation of Revenue [Line Items]
Net sales	2.4	3
United States
Disaggregation of Revenue [Line Items]
Net sales	3,830.8	3,427.6
United States | Operating Segments | Corporate
Disaggregation of Revenue [Line Items]
Net sales	1,907.8	1,732.9
United States | Operating Segments | Small Business
Disaggregation of Revenue [Line Items]
Net sales	391.5	355.6
United States | Operating Segments | Public
Disaggregation of Revenue [Line Items]
Net sales	1,525.3	1,330.7
United States | Operating Segments | Other
Disaggregation of Revenue [Line Items]
Net sales	6.2	8.4
Rest of World
Disaggregation of Revenue [Line Items]
Net sales	558.4	530.3
Rest of World | Operating Segments | Corporate
Disaggregation of Revenue [Line Items]
Net sales	3.2	3.3
Rest of World | Operating Segments | Small Business
Disaggregation of Revenue [Line Items]
Net sales	0	0
Rest of World | Operating Segments | Public
Disaggregation of Revenue [Line Items]
Net sales	0	0
Rest of World | Operating Segments | Other
Disaggregation of Revenue [Line Items]
Net sales	$ 555.2	$ 527

Subsequent Events (Details)

Subsequent Events (Details) - USD ($) $ in Millions	Apr. 21, 2020	Mar. 31, 2020	Dec. 31, 2019
Subsequent Event [Line Items]
Long-term debt		$ 3,491.9	$ 3,337.9
Senior Notes 4.125% Due 2025 | Subsequent Event
Subsequent Event [Line Items]
Long-term debt	$ 600
Interest rate in effect	4.125%