Investments and Financial Instruments Measured at Fair Value on a Recurring Basis (Detail) (Fair Value, Measurements, Recurring, USD $) In Millions	Jul. 31, 2011		Jan. 31, 2011
Assets
Foreign currency derivative contracts	$ 6.9	[1]	$ 5.1	[1]
Total	1,324.6		1,155.0
Liabilities
Foreign currency derivative contracts	2.6	[2]	1.2	[2]
Total	2.6		1.2
Mutual Funds
Assets
Marketable securities	33.8		31.3
Mutual Funds | Quoted Prices in Active Markets for Identical Assets ( Level 1)
Assets
Marketable securities	33.8		31.3
Certificates of deposit and time deposits
Assets
Cash equivalents	407.3	[3]	383.3	[3]
Marketable securities	5.1		29.0
Certificates of deposit and time deposits | Quoted Prices in Active Markets for Identical Assets ( Level 1)
Assets
Cash equivalents	0.1	[3]	97.9	[3]
Marketable securities			25.0
Certificates of deposit and time deposits | Significant Other Observable Inputs (Level 2)
Assets
Cash equivalents	407.2	[3]	285.4	[3]
Marketable securities	5.1		4.0
Taxable auction rate securities
Assets
Marketable securities	4.2		4.2
Taxable auction rate securities | Significant Unobservable Inputs (Level 3)
Assets
Marketable securities	4.2		4.2
US government agency securities
Assets
Marketable securities	62.9		60.1
US government agency securities | Quoted Prices in Active Markets for Identical Assets ( Level 1)
Assets
Marketable securities	62.9		60.1
Municipal securities
Assets
Marketable securities	13.1		13.4
Municipal securities | Quoted Prices in Active Markets for Identical Assets ( Level 1)
Assets
Marketable securities	13.1		13.4
Other
Assets
Marketable securities	0.3		0.3
Other | Quoted Prices in Active Markets for Identical Assets ( Level 1)
Assets
Marketable securities	0.3		0.3
Convertible Debt Securities
Assets
Convertible debt securities	14.5	[4]
Convertible Debt Securities | Significant Unobservable Inputs (Level 3)
Assets
Convertible debt securities	14.5	[4]
Sovereign Debt
Assets
Marketable securities			13.1
Sovereign Debt | Significant Other Observable Inputs (Level 2)
Assets
Marketable securities			13.1
Quoted Prices in Active Markets for Identical Assets ( Level 1)
Assets
Total	411.8		458.4
Quoted Prices in Active Markets for Identical Assets ( Level 1) | Commercial paper and corporate debt securities
Assets
Marketable securities	255.9		191.6
Quoted Prices in Active Markets for Identical Assets ( Level 1) | U.S. Treasury Securities
Assets
Marketable securities	45.7		38.8
Significant Other Observable Inputs (Level 2)
Assets
Foreign currency derivative contracts	6.9	[1]	5.1	[1]
Total	894.1		692.4
Liabilities
Foreign currency derivative contracts	2.6	[2]	1.2	[2]
Total	2.6		1.2
Significant Other Observable Inputs (Level 2) | Commercial Paper
Assets
Cash equivalents	306.2	[3]	331.0	[3]
Significant Other Observable Inputs (Level 2) | Money market funds
Assets
Cash equivalents	168.7	[3]	43.8	[3]
Significant Other Observable Inputs (Level 2) | Commercial paper and corporate debt securities
Assets
Marketable securities			10.0
Significant Unobservable Inputs (Level 3)
Assets
Total	18.7		4.2
Commercial Paper
Assets
Cash equivalents	306.2	[3]	331.0	[3]
Money market funds
Assets
Cash equivalents	168.7	[3]	43.8	[3]
Commercial paper and corporate debt securities
Assets
Marketable securities	255.9		201.6
U.S. Treasury Securities
Assets
Marketable securities	$ 45.7		$ 38.8

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

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

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

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