Financial Instruments Cost and Fair Value of Financial Instuments (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		6 Months Ended		12 Months Ended
	Jul. 31, 2013		Jul. 31, 2013		Jan. 31, 2013		Jul. 31, 2012	Jan. 31, 2012
Schedule of Available-for-sale Securities [Line Items]
Document Period End Date			Jul. 31, 2013
Cash and Cash Equivalents, at Carrying Value	$ 1,401.0		$ 1,401.0		$ 1,612.2		$ 930.2	$ 1,156.9
Derivative Instruments and Hedges, Carrying Amount	11.6	[1]	11.6	[1]	10.2	[1]
Unrealized Gain on Foreign Currency Derivatives, before Tax	6.9	[1]			9.2	[1]
Unrealized Loss on Foreign Currency Derivatives, before Tax	4.5	[1]			5.9	[1]
Derivative, Fair Value, Net	14.0	[1]	14.0	[1]	13.5	[1]
Derivative Asset, Fair Value, Gross Asset	14.4		14.4		17.4
Amortized Cost Securities	1,858.1		1,858.1		2,029.2
Unrealized Gain on Securities	17.0				16.9
Unrealized Loss on Securities	(8.1)				(8.1)
Fair Value, Assets Measured on Recurring Basis	1,867.0		1,867.0		2,038.0
Corporate Bond Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Cash and Cash Equivalents, at Carrying Value	1.5	[2]	1.5	[2]	1.8	[2]
Available-for-sale Securities, Gross Unrealized Gains	0	[2]			0	[2]
Available-for-sale Securities, Gross Unrealized Losses	0	[2]			0	[2]
Cash and Cash Equivalents, Fair Value Disclosure	1.5	[2]	1.5	[2]	1.8	[2]
Commercial Paper [Member]
Schedule of Available-for-sale Securities [Line Items]
Cash and Cash Equivalents, at Carrying Value	331.0	[2]	331.0	[2]	263.3	[2]
Available-for-sale Securities, Gross Unrealized Gains	0	[2]			0	[2]
Available-for-sale Securities, Gross Unrealized Losses	0	[2]			0	[2]
Cash and Cash Equivalents, Fair Value Disclosure	331.0	[2]	331.0	[2]	263.3	[2]
Money Market Funds [Member]
Schedule of Available-for-sale Securities [Line Items]
Cash and Cash Equivalents, at Carrying Value	244.6	[2]	244.6	[2]	596.3	[2]
Available-for-sale Securities, Gross Unrealized Gains	0	[2]			0	[2]
Available-for-sale Securities, Gross Unrealized Losses	0	[2]			0	[2]
Cash and Cash Equivalents, Fair Value Disclosure	244.6	[2]	244.6	[2]	596.3	[2]
Bank Time Deposits [Member]
Schedule of Available-for-sale Securities [Line Items]
Cash and Cash Equivalents, at Carrying Value	247.5	[2]	247.5	[2]	392.4	[2]
Available-for-sale Securities, Gross Unrealized Gains	0	[2]			0	[2]
Available-for-sale Securities, Gross Unrealized Losses	0	[2]			0	[2]
Cash and Cash Equivalents, Fair Value Disclosure	247.5	[2]	247.5	[2]	392.4	[2]
Level 1 [Member]
Schedule of Available-for-sale Securities [Line Items]
Derivative Asset, Fair Value, Gross Asset	0	[1]	0	[1]	0	[1]
Fair Value, Assets Measured on Recurring Basis	696.5		696.5		678.3
Level 1 [Member] | Corporate Bond Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Cash and Cash Equivalents, Fair Value Disclosure	1.5	[2]	1.5	[2]	1.8	[2]
Level 1 [Member] | Commercial Paper [Member]
Schedule of Available-for-sale Securities [Line Items]
Cash and Cash Equivalents, Fair Value Disclosure	0	[2]	0	[2]	0	[2]
Level 1 [Member] | Money Market Funds [Member]
Schedule of Available-for-sale Securities [Line Items]
Cash and Cash Equivalents, Fair Value Disclosure	0	[2]	0	[2]	0	[2]
Level 1 [Member] | Bank Time Deposits [Member]
Schedule of Available-for-sale Securities [Line Items]
Cash and Cash Equivalents, Fair Value Disclosure	7.8	[2]	7.8	[2]	17.2	[2]
Level 2 [Member]
Schedule of Available-for-sale Securities [Line Items]
Derivative Asset, Fair Value, Gross Asset	4.3	[1]	4.3	[1]	2.8	[1]
Fair Value, Assets Measured on Recurring Basis	1,139.4		1,139.4		1,327.3
Level 2 [Member] | Corporate Bond Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Cash and Cash Equivalents, Fair Value Disclosure	0	[2]	0	[2]	0	[2]
Level 2 [Member] | Commercial Paper [Member]
Schedule of Available-for-sale Securities [Line Items]
Cash and Cash Equivalents, Fair Value Disclosure	331.0	[2]	331.0	[2]	263.3	[2]
Level 2 [Member] | Money Market Funds [Member]
Schedule of Available-for-sale Securities [Line Items]
Cash and Cash Equivalents, Fair Value Disclosure	244.6	[2]	244.6	[2]	596.3	[2]
Level 2 [Member] | Bank Time Deposits [Member]
Schedule of Available-for-sale Securities [Line Items]
Cash and Cash Equivalents, Fair Value Disclosure	239.7	[2]	239.7	[2]	375.2	[2]
Level 3 [Member]
Schedule of Available-for-sale Securities [Line Items]
Derivative Asset, Fair Value, Gross Asset	9.7	[1]	9.7	[1]	10.7	[1]
Fair Value, Assets Measured on Recurring Basis	31.1		31.1		32.4
Level 3 [Member] | Corporate Bond Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Cash and Cash Equivalents, Fair Value Disclosure	0	[2]	0	[2]	0	[2]
Level 3 [Member] | Commercial Paper [Member]
Schedule of Available-for-sale Securities [Line Items]
Cash and Cash Equivalents, Fair Value Disclosure	0	[2]	0	[2]	0	[2]
Level 3 [Member] | Money Market Funds [Member]
Schedule of Available-for-sale Securities [Line Items]
Cash and Cash Equivalents, Fair Value Disclosure	0	[2]	0	[2]	0	[2]
Level 3 [Member] | Bank Time Deposits [Member]
Schedule of Available-for-sale Securities [Line Items]
Cash and Cash Equivalents, Fair Value Disclosure	0	[2]	0	[2]	0	[2]
Other Long-term Investments [Member] | US Treasury Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, Gross Unrealized Gains	0.1				0.1
Available-for-sale Securities, Gross Unrealized Losses	(0.1)				0
Available-for-sale Securities, Amortized Cost Basis	133.7		133.7		145.2
Available-for-sale Securities, Fair Value Disclosure	133.7		133.7		145.3
Other Long-term Investments [Member] | US Government Agencies Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, Gross Unrealized Gains	0				0.2
Available-for-sale Securities, Gross Unrealized Losses	0				0
Available-for-sale Securities, Amortized Cost Basis	39.0		39.0		50.8
Available-for-sale Securities, Fair Value Disclosure	39.0		39.0		51.0
Other Long-term Investments [Member] | US States and Political Subdivisions Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, Gross Unrealized Gains	0				0.1
Available-for-sale Securities, Gross Unrealized Losses	(0.2)				0
Available-for-sale Securities, Amortized Cost Basis	49.9		49.9		36.0
Available-for-sale Securities, Fair Value Disclosure	49.7		49.7		36.1
Other Long-term Investments [Member] | Sovereign Debt [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, Gross Unrealized Gains	0				0
Available-for-sale Securities, Gross Unrealized Losses	0				0
Available-for-sale Securities, Amortized Cost Basis	1.0		1.0		1.0
Available-for-sale Securities, Fair Value Disclosure	1.0		1.0		1.0
Other Long-term Investments [Member] | Corporate Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, Gross Unrealized Gains	0.7				1.4
Available-for-sale Securities, Gross Unrealized Losses	(0.2)				0
Available-for-sale Securities, Amortized Cost Basis	186.2		186.2		172.1
Available-for-sale Securities, Fair Value Disclosure	186.7		186.7		173.5
Other Long-term Investments [Member] | Taxable Auction Rate Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, Gross Unrealized Gains					0
Available-for-sale Securities, Gross Unrealized Losses					0
Available-for-sale Securities, Amortized Cost Basis					4.2
Available-for-sale Securities, Fair Value Disclosure					4.2
Other Long-term Investments [Member] | Level 1 [Member] | US Treasury Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, Fair Value Disclosure	133.7		133.7		145.3
Other Long-term Investments [Member] | Level 1 [Member] | US Government Agencies Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, Fair Value Disclosure	39.0		39.0		51.0
Other Long-term Investments [Member] | Level 1 [Member] | US States and Political Subdivisions Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, Fair Value Disclosure	49.7		49.7		36.1
Other Long-term Investments [Member] | Level 1 [Member] | Sovereign Debt [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, Fair Value Disclosure	0		0		0
Other Long-term Investments [Member] | Level 1 [Member] | Corporate Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, Fair Value Disclosure	186.7		186.7		173.5
Other Long-term Investments [Member] | Level 1 [Member] | Taxable Auction Rate Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, Fair Value Disclosure					0
Other Long-term Investments [Member] | Level 2 [Member] | US Treasury Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, Fair Value Disclosure	0		0		0
Other Long-term Investments [Member] | Level 2 [Member] | US Government Agencies Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, Fair Value Disclosure	0		0		0
Other Long-term Investments [Member] | Level 2 [Member] | US States and Political Subdivisions Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, Fair Value Disclosure	0		0		0
Other Long-term Investments [Member] | Level 2 [Member] | Sovereign Debt [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, Fair Value Disclosure	1.0		1.0		1.0
Other Long-term Investments [Member] | Level 2 [Member] | Corporate Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, Fair Value Disclosure	0		0		0
Other Long-term Investments [Member] | Level 2 [Member] | Taxable Auction Rate Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, Fair Value Disclosure					0
Other Long-term Investments [Member] | Level 3 [Member] | US Treasury Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, Fair Value Disclosure	0		0		0
Other Long-term Investments [Member] | Level 3 [Member] | US Government Agencies Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, Fair Value Disclosure	0		0		0
Other Long-term Investments [Member] | Level 3 [Member] | US States and Political Subdivisions Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, Fair Value Disclosure	0		0		0
Other Long-term Investments [Member] | Level 3 [Member] | Sovereign Debt [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, Fair Value Disclosure	0		0		0
Other Long-term Investments [Member] | Level 3 [Member] | Corporate Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, Fair Value Disclosure	0		0		0
Other Long-term Investments [Member] | Level 3 [Member] | Taxable Auction Rate Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, Fair Value Disclosure					4.2
Short-term Investments [Member]
Schedule of Available-for-sale Securities [Line Items]
Trading Securities, Short-term Investments, Amortized Cost	33.7		33.7		31.1
Trading Securities	39.9		39.9		35.3
Trading Securities, Unrealized Holding Gain	6.2				4.2
Trading Securities, Unrealized Holding Loss	0				0
Short-term Investments [Member] | Bank Time Deposits [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, Gross Unrealized Gains	0				0
Available-for-sale Securities, Gross Unrealized Losses	0				0
Available-for-sale Securities, Amortized Cost Basis	151.4		151.4		15.1
Available-for-sale Securities, Fair Value Disclosure	151.4		151.4		15.1
Short-term Investments [Member] | Commercial paper and corporate securities [member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, Gross Unrealized Gains	0.1				0.1
Available-for-sale Securities, Gross Unrealized Losses	(0.1)				0
Available-for-sale Securities, Amortized Cost Basis	261.8		261.8		122.9
Available-for-sale Securities, Fair Value Disclosure	261.8		261.8		123.0
Short-term Investments [Member] | US Treasury Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, Gross Unrealized Gains	0				0
Available-for-sale Securities, Gross Unrealized Losses	0				0
Available-for-sale Securities, Amortized Cost Basis	28.0		28.0		83.3
Available-for-sale Securities, Fair Value Disclosure	28.0		28.0		83.3
Short-term Investments [Member] | US Government Agencies Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, Gross Unrealized Gains	0				0
Available-for-sale Securities, Gross Unrealized Losses	0				0
Available-for-sale Securities, Amortized Cost Basis	87.4		87.4		79.5
Available-for-sale Securities, Fair Value Disclosure	87.4		87.4		79.5
Short-term Investments [Member] | US States and Political Subdivisions Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, Gross Unrealized Gains	0				0
Available-for-sale Securities, Gross Unrealized Losses	0				0
Available-for-sale Securities, Amortized Cost Basis	27.1		27.1		4.6
Available-for-sale Securities, Fair Value Disclosure	27.1		27.1		4.6
Short-term Investments [Member] | Sovereign Debt [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, Gross Unrealized Gains					0
Available-for-sale Securities, Gross Unrealized Losses					0
Available-for-sale Securities, Amortized Cost Basis					1.0
Available-for-sale Securities, Fair Value Disclosure					1.0
Short-term Investments [Member] | Other [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, Gross Unrealized Gains	0	[3]			0
Available-for-sale Securities, Gross Unrealized Losses	0	[3]			0
Available-for-sale Securities, Amortized Cost Basis	1.3	[3]	1.3	[3]	0.3
Available-for-sale Securities, Fair Value Disclosure	1.3	[3]	1.3	[3]	0.3
Short-term Investments [Member] | Level 1 [Member]
Schedule of Available-for-sale Securities [Line Items]
Trading Securities	39.9		39.9		35.3
Short-term Investments [Member] | Level 1 [Member] | Bank Time Deposits [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, Fair Value Disclosure	0		0		10.0
Short-term Investments [Member] | Level 1 [Member] | Commercial paper and corporate securities [member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, Fair Value Disclosure	95.3		95.3		40.4
Short-term Investments [Member] | Level 1 [Member] | US Treasury Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, Fair Value Disclosure	28.0		28.0		83.3
Short-term Investments [Member] | Level 1 [Member] | US Government Agencies Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, Fair Value Disclosure	87.4		87.4		79.5
Short-term Investments [Member] | Level 1 [Member] | US States and Political Subdivisions Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, Fair Value Disclosure	27.1		27.1		4.6
Short-term Investments [Member] | Level 1 [Member] | Sovereign Debt [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, Fair Value Disclosure					0
Short-term Investments [Member] | Level 1 [Member] | Other [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, Fair Value Disclosure	0.4	[3]	0.4	[3]	0.3
Short-term Investments [Member] | Level 2 [Member]
Schedule of Available-for-sale Securities [Line Items]
Trading Securities	0		0		0
Short-term Investments [Member] | Level 2 [Member] | Bank Time Deposits [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, Fair Value Disclosure	151.4		151.4		5.1
Short-term Investments [Member] | Level 2 [Member] | Commercial paper and corporate securities [member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, Fair Value Disclosure	166.5		166.5		82.6
Short-term Investments [Member] | Level 2 [Member] | US Treasury Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, Fair Value Disclosure	0		0		0
Short-term Investments [Member] | Level 2 [Member] | US Government Agencies Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, Fair Value Disclosure	0		0		0
Short-term Investments [Member] | Level 2 [Member] | US States and Political Subdivisions Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, Fair Value Disclosure	0		0		0
Short-term Investments [Member] | Level 2 [Member] | Sovereign Debt [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, Fair Value Disclosure					1.0
Short-term Investments [Member] | Level 2 [Member] | Other [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, Fair Value Disclosure	0.9	[3]	0.9	[3]	0
Short-term Investments [Member] | Level 3 [Member]
Schedule of Available-for-sale Securities [Line Items]
Trading Securities	0		0		0
Short-term Investments [Member] | Level 3 [Member] | Bank Time Deposits [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, Fair Value Disclosure	0		0		0
Short-term Investments [Member] | Level 3 [Member] | Commercial paper and corporate securities [member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, Fair Value Disclosure	0		0		0
Short-term Investments [Member] | Level 3 [Member] | US Treasury Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, Fair Value Disclosure	0		0		0
Short-term Investments [Member] | Level 3 [Member] | US Government Agencies Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, Fair Value Disclosure	0		0		0
Short-term Investments [Member] | Level 3 [Member] | US States and Political Subdivisions Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, Fair Value Disclosure	0		0		0
Short-term Investments [Member] | Level 3 [Member] | Sovereign Debt [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, Fair Value Disclosure					0
Short-term Investments [Member] | Level 3 [Member] | Other [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, Fair Value Disclosure	0	[3]	0	[3]	0
Other Assets [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Debt Securities, Amortized Cost Basis	21.4	[4]	21.4	[4]	18.1	[5]
Available-for-sale Debt Securities Gross Unrealized Gain	3.0	[4]			1.6	[5]
Available-for-sale Debt Securities, Gross Unrealized Loss	3.0	[4]			2.2	[5]
Convertible Debt Securities, Fair Value Disclosure	21.4	[4]	21.4	[4]	17.5	[5]
Other Assets [Member] | Level 1 [Member]
Schedule of Available-for-sale Securities [Line Items]
Convertible Debt Securities, Fair Value Disclosure	0	[4]	0	[4]	0	[5]
Other Assets [Member] | Level 2 [Member]
Schedule of Available-for-sale Securities [Line Items]
Convertible Debt Securities, Fair Value Disclosure	0	[4]	0	[4]	0	[5]
Other Assets [Member] | Level 3 [Member]
Schedule of Available-for-sale Securities [Line Items]
Convertible Debt Securities, Fair Value Disclosure	$ 21.4	[4]	$ 21.4	[4]	$ 17.5	[5]

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

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

[3] Consists of sovereign debt and other short-term securities.

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

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