Dispositions (Schedule of Major Class of Asset and Liabilities Included in Discontinued Operations) (Details) (USD $) In Millions, unless otherwise specified	Jan. 30, 2015	Jan. 31, 2014	Jan. 31, 2013
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Total current assets	$ 6	$ 39
Total current liabilities	10	6
SAIC
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Cash and cash equivalents			1
Receivables, net			717
Inventory, prepaid expenses and other current assets			101
Total current assets			819
Property, plant and equipment, net			29
Intangible assets, net			6
Goodwill			491
Deferred income taxes			2
Other assets			1
Total assets			1,348
Accounts payable and accrued liabilities			461
Accrued payroll and employee benefits			185
Notes payable and long-term debt			1
Total current liabilities			647
Non-current liabilities			0
Total liabilities			$ 647