Segment Information Segment Reporting, by Products and Services (Details) (USD $)	3 Months Ended								12 Months Ended
	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014		Dec. 31, 2013		Dec. 31, 2012
Net Sales from External Customer [Line Items]
Net sales to customers outside of the US, Percent									4.00%		4.00%		4.00%
Revenue, Net	$ 3,050,100,000	$ 3,266,100,000	$ 3,106,000,000	$ 2,652,300,000	$ 2,713,300,000	$ 2,864,300,000	$ 2,779,300,000	$ 2,411,700,000	$ 12,074,500,000		$ 10,768,600,000		$ 10,128,200,000
Revenue net, by Product and Service, Percentage									100.00%		100.00%		100.00%
Long-Lived Assets in Foreign Countries, Percent	1.00%				1.00%				1.00%		1.00%
Notebooks/Mobile Devices [Member]
Net Sales from External Customer [Line Items]
Revenue, Net									2,352,300,000		1,698,400,000		1,462,800,000
Revenue net, by Product and Service, Percentage									19.50%		15.80%		14.40%
NetComm Products [Member]
Net Sales from External Customer [Line Items]
Revenue, Net									1,615,900,000		1,486,300,000		1,351,500,000
Revenue net, by Product and Service, Percentage									13.40%		13.80%		13.30%
Enterprise and Data Storage (Including Drives) [Member]
Net Sales from External Customer [Line Items]
Revenue, Net									1,024,300,000		999,200,000		981,500,000
Revenue net, by Product and Service, Percentage									8.50%		9.30%		9.70%
Other Hardware [Member]
Net Sales from External Customer [Line Items]
Revenue, Net									4,549,200,000		4,178,500,000		4,075,700,000
Revenue net, by Product and Service, Percentage									37.60%		38.80%		40.30%
Software [Member]
Net Sales from External Customer [Line Items]
Revenue, Net									2,076,700,000		1,993,100,000		1,877,700,000
Revenue net, by Product and Service, Percentage									17.20%		18.50%		18.50%
Services [Member]
Net Sales from External Customer [Line Items]
Revenue, Net									371,400,000		332,700,000		285,000,000
Revenue net, by Product and Service, Percentage									3.10%		3.10%		2.80%
Other [Member]
Net Sales from External Customer [Line Items]
Revenue, Net									84,700,000	[1]	80,400,000	[1]	94,000,000	[1]
Revenue net, by Product and Service, Percentage									0.70%	[1]	0.70%	[1]	1.00%	[1]
Public [Member]
Net Sales from External Customer [Line Items]
Revenue, Net	1,169,100,000	1,468,800,000	1,271,600,000	969,900,000	990,500,000	1,244,600,000	1,082,600,000	846,800,000
Federal [Member] | Public [Member]
Net Sales from External Customer [Line Items]
Revenue, Net									$ 884,200,000		$ 764,400,000		$ 964,700,000

[1] Includes items such as delivery charges to customers and certain commission revenue.