Debt - Additional Information (Detail) (USD $)	1 Months Ended	9 Months Ended	12 Months Ended
	Jun. 30, 2010	Mar. 31, 2012	Jun. 30, 2011
Debt Instrument [Line Items]
Long-term debt		$ 11,938,000,000	$ 11,921,000,000	[1]
Estimated fair value of our long-term debt, including convertible debt		13,000,000,000	12,100,000,000
Proceeds from convertible debt offering	1,240,000,000
Unamortized discount		62,000,000	79,000,000
Capped call options, cap price	37.16
Derivative asset		387,000,000	416,000,000
Purchased Call Option
Debt Instrument [Line Items]
Derivative asset	40,000,000
Debt
Debt Instrument [Line Items]
Proceeds from convertible debt offering	1,180,000,000
Equity
Debt Instrument [Line Items]
Proceeds from convertible debt offering	58,000,000
Convertible Debt
Debt Instrument [Line Items]
Principal amount of outstanding long-term debt	1,250,000,000	1,250,000,000	1,250,000,000
Debt instrument maturity date		Jun. 15, 2013	Jun. 15, 2013
Principal amount of each convertible note	1,000
Shares of Microsoft common stock into which each $1,000 principal amount of notes may convert	29.94
Conversion price per share of convertible notes	$ 33.40
Net carrying amount of our convertible debt		1,200,000,000
Unamortized discount		$ 24,000,000
Terms of conversion change date	Mar. 15, 2013

[1] Derived from audited financial statements.