Financial Instruments Cost and Fair Value of Financial Instruments (Details) (USD $) In Millions, unless otherwise specified	Oct. 31, 2014		Jan. 31, 2014		Oct. 31, 2013	Jan. 31, 2013
Schedule of Available-for-sale Securities [Line Items]
Cash equivalents	$ 1,345.0		$ 1,853.0		$ 1,473.4	$ 1,612.2
Total	783.8
Derivative contracts, Amortized Cost	6.2	[1]	10.8	[1]
Derivative contracts, Gross unrealized gains	21.4	[1]	14.8	[1]
Derivative contracts, Gross unrealized losses	(7.2)	[1]	(6.0)	[1]
Derivative contracts, Fair Value	20.4	[1]	19.6	[1]
Amortized Cost	1,503.2		1,545.3
Gross unrealized gains	32.3		22.4
Gross unrealized losses	(15.5)		(10.5)
Fair Value	1,520.0		1,557.2
Short-term available for sale
Schedule of Available-for-sale Securities [Line Items]
Mutual funds, Amortized Cost	38.7		35.6
Mutual funds, Gross unrealized gains	5.4		3.3
Mutual funds, Gross unrealized losses	0		0
Mutual funds, Fair Value	44.1		38.9
Short-term available for sale | Commercial paper and certificates of deposit
Schedule of Available-for-sale Securities [Line Items]
Marketable securities, Amortized Cost	242.5		261.0
Marketable securities, Gross unrealized gains	0		0
Marketable securities, Gross unrealized losses	0		0
Marketable securities, Fair Value	242.5		261.0
Short-term available for sale | Time deposits
Schedule of Available-for-sale Securities [Line Items]
Marketable securities, Amortized Cost	132.3		37.1
Marketable securities, Gross unrealized gains	0		0
Marketable securities, Gross unrealized losses	0		0
Marketable securities, Fair Value	132.3		37.1
Short-term available for sale | Corporate debt securities
Schedule of Available-for-sale Securities [Line Items]
Marketable securities, Amortized Cost	99.6
Marketable securities, Gross unrealized gains	0
Marketable securities, Gross unrealized losses	0
Marketable securities, Fair Value	99.6
Short-term available for sale | Corporate debt securities
Schedule of Available-for-sale Securities [Line Items]
Marketable securities, Amortized Cost			42.7
Marketable securities, Gross unrealized gains			0
Marketable securities, Gross unrealized losses			0
Marketable securities, Fair Value			42.7
Short-term available for sale | Municipal securities
Schedule of Available-for-sale Securities [Line Items]
Marketable securities, Amortized Cost			11.3
Marketable securities, Gross unrealized gains			0
Marketable securities, Gross unrealized losses			0
Marketable securities, Fair Value			11.3
Short-term available for sale | Treasury bill
Schedule of Available-for-sale Securities [Line Items]
Marketable securities, Amortized Cost	6.0
Marketable securities, Gross unrealized gains	0
Marketable securities, Gross unrealized losses	0
Marketable securities, Fair Value	6.0
Short-term available for sale | Municipal securities
Schedule of Available-for-sale Securities [Line Items]
Marketable securities, Amortized Cost	22.3		11.7
Marketable securities, Gross unrealized gains	0.1		0
Marketable securities, Gross unrealized losses	0		0
Marketable securities, Fair Value	22.4		11.7
Short-term available for sale | Other
Schedule of Available-for-sale Securities [Line Items]
Marketable securities, Amortized Cost	9.5	[2]	11.4	[3]
Marketable securities, Gross unrealized gains	0	[2]	0	[3]
Marketable securities, Gross unrealized losses	0	[2]	0	[3]
Marketable securities, Fair Value	9.5	[2]	11.4	[3]
Long-term available for sale | Corporate debt securities
Schedule of Available-for-sale Securities [Line Items]
Marketable securities, Amortized Cost	186.4		179.7
Marketable securities, Gross unrealized gains	0.4		0.7
Marketable securities, Gross unrealized losses	(0.2)		(0.1)
Marketable securities, Fair Value	186.6		180.3
Long-term available for sale | Corporate debt securities
Schedule of Available-for-sale Securities [Line Items]
Marketable securities, Amortized Cost	40.7		43.3
Marketable securities, Gross unrealized gains	0.1		0.1
Marketable securities, Gross unrealized losses	0		0
Marketable securities, Fair Value	40.8		43.4
Long-term available for sale | Municipal securities
Schedule of Available-for-sale Securities [Line Items]
Marketable securities, Amortized Cost	10.0		9.8
Marketable securities, Gross unrealized gains	0		0
Marketable securities, Gross unrealized losses	0		0
Marketable securities, Fair Value	10.0		9.8
Long-term available for sale | Municipal securities
Schedule of Available-for-sale Securities [Line Items]
Marketable securities, Amortized Cost	18.0		43.5
Marketable securities, Gross unrealized gains	0.1		0.3
Marketable securities, Gross unrealized losses	0		0
Marketable securities, Fair Value	18.1		43.8
Convertible debt securities
Schedule of Available-for-sale Securities [Line Items]
Total	16.5	[4]	21.4	[4]
Convertible debt securities, Gross unrealized gains	4.8	[4]	3.2	[4]
Convertible debt securities, Gross unrealized losses	(8.1)	[4]	(4.4)	[4]
Convertible debt securities, Fair Value	13.2	[4]	20.2	[4]
Certificates of deposit and time deposits
Schedule of Available-for-sale Securities [Line Items]
Cash equivalents	328.1	[5]	280.7	[5]
Cash equivalents, Fair Value	328.1	[5]	280.7	[5]
Agency discount note
Schedule of Available-for-sale Securities [Line Items]
Cash equivalents	57.3	[5]
Cash equivalents, Fair Value	57.3	[5]
Commercial paper
Schedule of Available-for-sale Securities [Line Items]
Cash equivalents	216.8	[5]	280.5	[5]
Cash equivalents, Fair Value	216.8	[5]	280.5	[5]
Municipal securities
Schedule of Available-for-sale Securities [Line Items]
Cash equivalents			2.0	[5]
Cash equivalents, Fair Value			2.0	[5]
Money market funds
Schedule of Available-for-sale Securities [Line Items]
Cash equivalents	65.3	[5]	262.8	[5]
Cash equivalents, Fair Value	65.3	[5]	262.8	[5]
Other
Schedule of Available-for-sale Securities [Line Items]
Cash equivalents	7.0	[5],[6]
Cash equivalents, Fair Value	7.0	[5],[6]
Level 1
Schedule of Available-for-sale Securities [Line Items]
Derivative contracts, Fair Value	0	[1]	0	[1]
Fair Value	684.0		521.1
Level 1 | Short-term available for sale
Schedule of Available-for-sale Securities [Line Items]
Mutual funds, Fair Value	44.1		38.9
Level 1 | Short-term available for sale | Commercial paper and certificates of deposit
Schedule of Available-for-sale Securities [Line Items]
Marketable securities, Fair Value	6.2		95.4
Level 1 | Short-term available for sale | Time deposits
Schedule of Available-for-sale Securities [Line Items]
Marketable securities, Fair Value	0		0
Level 1 | Short-term available for sale | Corporate debt securities
Schedule of Available-for-sale Securities [Line Items]
Marketable securities, Fair Value	99.6
Level 1 | Short-term available for sale | Corporate debt securities
Schedule of Available-for-sale Securities [Line Items]
Marketable securities, Fair Value			42.7
Level 1 | Short-term available for sale | Municipal securities
Schedule of Available-for-sale Securities [Line Items]
Marketable securities, Fair Value			11.3
Level 1 | Short-term available for sale | Treasury bill
Schedule of Available-for-sale Securities [Line Items]
Marketable securities, Fair Value	6.0
Level 1 | Short-term available for sale | Municipal securities
Schedule of Available-for-sale Securities [Line Items]
Marketable securities, Fair Value	22.4		11.7
Level 1 | Short-term available for sale | Other
Schedule of Available-for-sale Securities [Line Items]
Marketable securities, Fair Value	9.5	[2]	11.4	[3]
Level 1 | Long-term available for sale | Corporate debt securities
Schedule of Available-for-sale Securities [Line Items]
Marketable securities, Fair Value	186.6		180.3
Level 1 | Long-term available for sale | Corporate debt securities
Schedule of Available-for-sale Securities [Line Items]
Marketable securities, Fair Value	40.8		43.4
Level 1 | Long-term available for sale | Municipal securities
Schedule of Available-for-sale Securities [Line Items]
Marketable securities, Fair Value	10.0		9.8
Level 1 | Long-term available for sale | Municipal securities
Schedule of Available-for-sale Securities [Line Items]
Marketable securities, Fair Value	18.1		43.8
Level 1 | Convertible debt securities
Schedule of Available-for-sale Securities [Line Items]
Convertible debt securities, Fair Value	0	[4]	0	[4]
Level 1 | Certificates of deposit and time deposits
Schedule of Available-for-sale Securities [Line Items]
Cash equivalents, Fair Value	165.1	[5]	30.4	[5]
Level 1 | Agency discount note
Schedule of Available-for-sale Securities [Line Items]
Cash equivalents, Fair Value	57.3	[5]
Level 1 | Commercial paper
Schedule of Available-for-sale Securities [Line Items]
Cash equivalents, Fair Value	16.3	[5]	0	[5]
Level 1 | Municipal securities
Schedule of Available-for-sale Securities [Line Items]
Cash equivalents, Fair Value			2.0	[5]
Level 1 | Money market funds
Schedule of Available-for-sale Securities [Line Items]
Cash equivalents, Fair Value	0	[5]	0	[5]
Level 1 | Other
Schedule of Available-for-sale Securities [Line Items]
Cash equivalents, Fair Value	2.0	[5],[6]
Level 2
Schedule of Available-for-sale Securities [Line Items]
Derivative contracts, Fair Value	16.7	[1]	10.5	[1]
Fair Value	819.1		1,006.8
Level 2 | Short-term available for sale
Schedule of Available-for-sale Securities [Line Items]
Mutual funds, Fair Value	0		0
Level 2 | Short-term available for sale | Commercial paper and certificates of deposit
Schedule of Available-for-sale Securities [Line Items]
Marketable securities, Fair Value	236.3		165.6
Level 2 | Short-term available for sale | Time deposits
Schedule of Available-for-sale Securities [Line Items]
Marketable securities, Fair Value	132.3		37.1
Level 2 | Short-term available for sale | Corporate debt securities
Schedule of Available-for-sale Securities [Line Items]
Marketable securities, Fair Value	0
Level 2 | Short-term available for sale | Corporate debt securities
Schedule of Available-for-sale Securities [Line Items]
Marketable securities, Fair Value			0
Level 2 | Short-term available for sale | Municipal securities
Schedule of Available-for-sale Securities [Line Items]
Marketable securities, Fair Value			0
Level 2 | Short-term available for sale | Treasury bill
Schedule of Available-for-sale Securities [Line Items]
Marketable securities, Fair Value	0
Level 2 | Short-term available for sale | Municipal securities
Schedule of Available-for-sale Securities [Line Items]
Marketable securities, Fair Value	0		0
Level 2 | Short-term available for sale | Other
Schedule of Available-for-sale Securities [Line Items]
Marketable securities, Fair Value	0	[2]	0	[3]
Level 2 | Long-term available for sale | Corporate debt securities
Schedule of Available-for-sale Securities [Line Items]
Marketable securities, Fair Value	0		0
Level 2 | Long-term available for sale | Corporate debt securities
Schedule of Available-for-sale Securities [Line Items]
Marketable securities, Fair Value	0		0
Level 2 | Long-term available for sale | Municipal securities
Schedule of Available-for-sale Securities [Line Items]
Marketable securities, Fair Value	0		0
Level 2 | Long-term available for sale | Municipal securities
Schedule of Available-for-sale Securities [Line Items]
Marketable securities, Fair Value	0		0
Level 2 | Convertible debt securities
Schedule of Available-for-sale Securities [Line Items]
Convertible debt securities, Fair Value	0	[4]	0	[4]
Level 2 | Certificates of deposit and time deposits
Schedule of Available-for-sale Securities [Line Items]
Cash equivalents, Fair Value	163.0	[5]	250.3	[5]
Level 2 | Agency discount note
Schedule of Available-for-sale Securities [Line Items]
Cash equivalents, Fair Value	0	[5]
Level 2 | Commercial paper
Schedule of Available-for-sale Securities [Line Items]
Cash equivalents, Fair Value	200.5	[5]	280.5	[5]
Level 2 | Municipal securities
Schedule of Available-for-sale Securities [Line Items]
Cash equivalents, Fair Value			0	[5]
Level 2 | Money market funds
Schedule of Available-for-sale Securities [Line Items]
Cash equivalents, Fair Value	65.3	[5]	262.8	[5]
Level 2 | Other
Schedule of Available-for-sale Securities [Line Items]
Cash equivalents, Fair Value	5.0	[5],[6]
Level 3
Schedule of Available-for-sale Securities [Line Items]
Derivative contracts, Fair Value	3.7	[1]	9.1	[1]
Fair Value	16.9		29.3
Level 3 | Short-term available for sale
Schedule of Available-for-sale Securities [Line Items]
Mutual funds, Fair Value	0		0
Level 3 | Short-term available for sale | Commercial paper and certificates of deposit
Schedule of Available-for-sale Securities [Line Items]
Marketable securities, Fair Value	0		0
Level 3 | Short-term available for sale | Time deposits
Schedule of Available-for-sale Securities [Line Items]
Marketable securities, Fair Value	0		0
Level 3 | Short-term available for sale | Corporate debt securities
Schedule of Available-for-sale Securities [Line Items]
Marketable securities, Fair Value	0
Level 3 | Short-term available for sale | Corporate debt securities
Schedule of Available-for-sale Securities [Line Items]
Marketable securities, Fair Value			0
Level 3 | Short-term available for sale | Municipal securities
Schedule of Available-for-sale Securities [Line Items]
Marketable securities, Fair Value			0
Level 3 | Short-term available for sale | Treasury bill
Schedule of Available-for-sale Securities [Line Items]
Marketable securities, Fair Value	0
Level 3 | Short-term available for sale | Municipal securities
Schedule of Available-for-sale Securities [Line Items]
Marketable securities, Fair Value	0		0
Level 3 | Short-term available for sale | Other
Schedule of Available-for-sale Securities [Line Items]
Marketable securities, Fair Value	0	[2]	0	[3]
Level 3 | Long-term available for sale | Corporate debt securities
Schedule of Available-for-sale Securities [Line Items]
Marketable securities, Fair Value	0		0
Level 3 | Long-term available for sale | Corporate debt securities
Schedule of Available-for-sale Securities [Line Items]
Marketable securities, Fair Value	0		0
Level 3 | Long-term available for sale | Municipal securities
Schedule of Available-for-sale Securities [Line Items]
Marketable securities, Fair Value	0		0
Level 3 | Long-term available for sale | Municipal securities
Schedule of Available-for-sale Securities [Line Items]
Marketable securities, Fair Value	0		0
Level 3 | Convertible debt securities
Schedule of Available-for-sale Securities [Line Items]
Convertible debt securities, Fair Value	13.2	[4]	20.2	[4]
Level 3 | Certificates of deposit and time deposits
Schedule of Available-for-sale Securities [Line Items]
Cash equivalents, Fair Value	0	[5]	0	[5]
Level 3 | Agency discount note
Schedule of Available-for-sale Securities [Line Items]
Cash equivalents, Fair Value	0	[5]
Level 3 | Commercial paper
Schedule of Available-for-sale Securities [Line Items]
Cash equivalents, Fair Value	0	[5]	0	[5]
Level 3 | Municipal securities
Schedule of Available-for-sale Securities [Line Items]
Cash equivalents, Fair Value			0	[5]
Level 3 | Money market funds
Schedule of Available-for-sale Securities [Line Items]
Cash equivalents, Fair Value	0	[5]	0	[5]
Level 3 | Other
Schedule of Available-for-sale Securities [Line Items]
Cash equivalents, Fair Value	$ 0	[5],[6]

[1] Included in “Prepaid expenses and other current assets,” “Other assets,” or “Other accrued liabilities” in the accompanying Condensed Consolidated Balance Sheets.

[2] Consists of U.S. government agency securities, agency discount notes, and other short-term securities.

[3] Consists of agency discount notes, U.S. treasury bills, and other short-term securities.

[4] Considered “available for sale” and included in “Other assets” in the accompanying Condensed Consolidated Balance Sheets.

[5] Included in “Cash and cash equivalents” in the accompanying Condensed Consolidated Balance Sheets.

[6] Consists of international government bonds and municipal securities.