Investments and Financial Instruments Measured at Fair Value on a Recurring Basis (Detail) (Fair Value, Measurements, Recurring, USD $) In Millions, unless otherwise specified	Oct. 31, 2011		Jan. 31, 2011
Assets
Derivative contracts	$ 12.5	[1]	$ 5.1	[2]
Total	1,256.6		1,155.0
Liabilities
Derivative contracts	3.1	[3]	1.2	[3]
Total	3.1		1.2
Certificates of deposit and time deposits
Assets
Cash equivalents	463.6	[4]	383.3	[4]
Marketable securities	4.8		29.0
Commercial Paper
Assets
Cash equivalents	305.2	[4]	331.0	[4]
Money market funds
Assets
Cash equivalents	32.0	[4]	43.8	[4]
Commercial paper and corporate debt securities
Assets
Marketable securities	258.5		201.6
US government agency securities
Assets
Marketable securities	77.2		60.1
U.S. Treasury Securities
Assets
Marketable securities	40.1		38.8
Mutual Funds
Assets
Marketable securities	32.7		31.3
Municipal securities
Assets
Marketable securities	13.1		13.4
Taxable auction rate securities
Assets
Marketable securities	4.2		4.2
Other
Assets
Marketable securities	0.3		0.3
Convertible Debt Securities
Assets
Convertible debt securities	12.4	[5]
Sovereign Debt
Assets
Marketable securities			13.1
Quoted Prices in Active Markets for Identical Assets ( Level 1)
Assets
Total	431.2		458.4
Quoted Prices in Active Markets for Identical Assets ( Level 1) | Certificates of deposit and time deposits
Assets
Cash equivalents	9.3	[4]	97.9	[4]
Marketable securities			25.0
Quoted Prices in Active Markets for Identical Assets ( Level 1) | Commercial paper and corporate debt securities
Assets
Marketable securities	258.5		191.6
Quoted Prices in Active Markets for Identical Assets ( Level 1) | US government agency securities
Assets
Marketable securities	77.2		60.1
Quoted Prices in Active Markets for Identical Assets ( Level 1) | U.S. Treasury Securities
Assets
Marketable securities	40.1		38.8
Quoted Prices in Active Markets for Identical Assets ( Level 1) | Mutual Funds
Assets
Marketable securities	32.7		31.3
Quoted Prices in Active Markets for Identical Assets ( Level 1) | Municipal securities
Assets
Marketable securities	13.1		13.4
Quoted Prices in Active Markets for Identical Assets ( Level 1) | Other
Assets
Marketable securities	0.3		0.3
Significant Other Observable Inputs (Level 2)
Assets
Derivative contracts	7.4	[1]	5.1	[2]
Total	803.7		692.4
Liabilities
Derivative contracts	3.1	[3]	1.2	[3]
Total	3.1		1.2
Significant Other Observable Inputs (Level 2) | Certificates of deposit and time deposits
Assets
Cash equivalents	454.3	[4]	285.4	[4]
Marketable securities	4.8		4.0
Significant Other Observable Inputs (Level 2) | Commercial Paper
Assets
Cash equivalents	305.2	[4]	331.0	[4]
Significant Other Observable Inputs (Level 2) | Money market funds
Assets
Cash equivalents	32.0	[4]	43.8	[4]
Significant Other Observable Inputs (Level 2) | Commercial paper and corporate debt securities
Assets
Marketable securities			10.0
Significant Other Observable Inputs (Level 2) | Sovereign Debt
Assets
Marketable securities			13.1
Significant Unobservable Inputs (Level 3)
Assets
Derivative contracts	5.1	[1]
Total	21.7		4.2
Significant Unobservable Inputs (Level 3) | Taxable auction rate securities
Assets
Marketable securities	4.2		4.2
Significant Unobservable Inputs (Level 3) | Convertible Debt Securities
Assets
Convertible debt securities	$ 12.4	[5]

[1] Included in "Prepaid expenses and other current assets" or "Other assets" in the accompanying Condensed Consolidated Balance Sheets.

[2] Included in "Prepaid expenses and other current assets" in the accompanying Condensed Consolidated Balance Sheets.

[3] Included in "Other accrued liabilities" in the accompanying Condensed Consolidated Balance Sheets.

[4] Included in "Cash and cash equivalents" in the accompanying Condensed Consolidated Balance Sheets.

[5] Included in "Other assets" in the accompanying Condensed Consolidated Balance Sheets.