Fair Value Measurements (Details) - USD ($) $ in Millions	Aug. 01, 2015	Jan. 31, 2015
Recurring [Member] | Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Money market funds	$ 0	$ 14
Fair Value [Member] | Senior Notes [Member] | January 2018 Notes [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long-term Debt, Fair Value	503	507
Fair Value [Member] | Senior Notes [Member] | January 2023 Notes [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long-term Debt, Fair Value	498	511
Carrying Value [Member] | Senior Notes [Member] | January 2018 Notes [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long-term Debt, Fair Value	497	497
Carrying Value [Member] | Senior Notes [Member] | January 2023 Notes [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long-term Debt, Fair Value	$ 496	$ 496