Long-Term Debt (Tables)

12 Months Ended

Dec. 31, 2019

Debt Disclosure [Abstract]

Carrying Value of Long-Term Debt

		As of December 31, 2019					As of December 31, 2018
	Maturity Date	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	5.00	%	51.0			—	%	—
Total credit facilities				51.0					—
Term Loans
CDW UK term loan(1)	August 2021	2.19	%	61.0			2.29	%	65.0
Senior secured term loan facility	October 2026	3.55	%	1,438.3			4.10	%	1,453.2
Total term loans				1,499.3					1,518.2
Unsecured Senior Notes
Senior notes due 2023 ("2023 Senior Notes")	September 2023	—	%	—			5.00	%	525.0
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			—	%	—
Total unsecured senior notes				1,775.0					1,700.0
Other long-term obligations				12.6					8.3
Unamortized deferred financing fees				(20.6		)			(17.9		)
Current maturities of long-term debt				(34.1		)			(25.3		)
Total long-term debt				$	3,283.2				$	3,183.3

(1)

British pound-denominated debt facilities.

Schedule of Long-term Debt Maturities

A summary of total debt maturities is as follows:    

Years ending December 31,	Debt Maturities
2020	$	34.1
2021	69.3
2022	65.9
2023	14.9
2024	589.9
Thereafter	2,563.8
Total debt maturities	$	3,337.9

Schedule of Carrying Values and Estimated Fair Values of Debt Instruments

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 costs, are as follows:

	December 31,
	2019		2018
Fair value	$	3,447.5	$	3,145.8
Carrying value	3,337.9		3,226.5