Investments (Details) (USD $) In Millions, unless otherwise specified	1 Months Ended	3 Months Ended		6 Months Ended		12 Months Ended
	Mar. 31, 2010 company	Aug. 27, 2011		Aug. 27, 2011 investments		Mar. 01, 2008	Feb. 26, 2011		Aug. 28, 2010
Schedule of Investments
Total short-term investments		$ 80		$ 80			$ 22		$ 2
Total equity and other investments		284		284			328		293
Interval of auction process		seven, 28 and 35 days
Securities redeemed		8
Investments in portfolio (investments)				19
Aggregate value of failed auctions		93		93
Auction Rate Securities, Maturity Date Range, End (in years)				30
Marketable Equity Security, Ownership Percentage as of Purchase Date (as a percent)						3.00%
Accumulated Other Comprehensive Income (Loss), Available-for-sale Securities Adjustment, Net of Tax		51		51			72		29
Number of companies formed after CPW demerger	2
Percentage ownership of former CPW in Best Buy Europe, included in Carphone Warehouse holding company (as a percent)	50.00%
Money Market Fund
Schedule of Investments
Total short-term investments		0		0			2		2
U.S. Treasury bills
Schedule of Investments
Total short-term investments		80		80			20		0
Debt Securities (Auction-Rate Securities)
Schedule of Investments
Total equity and other investments		88		88			110		134
Investments, Fair Value Disclosure		88	[1]	88	[1]		110	[1]	134	[1]
Auction Rate Securities, Par Value		93		93			115		144
Weighted Average Interest Rate Percentage (as a percent)		0.40%		0.40%			0.80%		0.91%
Percentage of Portfolio With Credit Rating AAA/Aaa (as a percent)		88.00%		88.00%
Percentage of Portfolio With Credit Rating AA/Aa (as a percent)		3.00%		3.00%
Percentage of Portfolio With Credit Rating A/A (as a percent)		9.00%		9.00%
Auction Rate Securities, Maturity Date Range, Start (in years)				5
Pre-tax unrealized gain (loss) in accumulated other comprehensive income				(5)
Accumulated Other Comprehensive Income (Loss), Available-for-sale Securities Adjustment, Net of Tax		(3)		(3)			(3)		(6)
Student loan bonds
Schedule of Investments
Investments, Fair Value Disclosure		86		86			108		116
Guaranteed or Insured Percentage, Low Range (as a percent)		95.00%		95.00%
Guaranteed or Insured Percentage, High Range (as a percent)		100.00%		100.00%
Municipal revenue bonds
Schedule of Investments
Investments, Fair Value Disclosure		2		2			2		18
Percentage Insured by Rated Bond Insurers (as a percent)		100.00%		100.00%
Marketable Equity Securities
Schedule of Investments
Total equity and other investments		122		122			146		97
Pre-tax unrealized gain (loss) in accumulated other comprehensive income				63
Accumulated Other Comprehensive Income (Loss), Available-for-sale Securities Adjustment, Net of Tax		54		54			75		35
Common stock of Talk Talk Telecom Group PLC
Schedule of Investments
Total equity and other investments		69		69			62		51
Common stock of Carphone Warehouse Group plc
Schedule of Investments
Total equity and other investments		53		53			84		44
Marketable Equity Securities, Other
Schedule of Investments
Total equity and other investments		0		0			0		2
Other Investments
Schedule of Investments
Total equity and other investments		$ 74		$ 74			$ 72		$ 62

[1] The par value and weighted-average interest rates (taxable equivalent) of our ARS were $93, $115 and $144, and 0.40%, 0.80% and 0.91%, respectively, at August 27, 2011, February 26, 2011, and August 28, 2010, respectively.