Financial Instruments Cost and Fair Value of Financial Instuments (Details) (USD $) In Millions, unless otherwise specified	6 Months Ended		12 Months Ended
	Jul. 31, 2012		Jan. 31, 2012		Jul. 31, 2011	Jan. 31, 2011
Schedule of Available-for-sale Securities [Line Items]
Cash and Cash Equivalents, at Carrying Value	$ 930.2		$ 1,156.9		$ 1,131.5	$ 1,075.1
Amortized Cost Securities	1,407.8		1,327.7
Unrealized Gain on Securities	14.1		9.8
Unrealized Loss on Securities	(4.8)		(2.5)
Fair Value, Assets Measured on Recurring Basis	1,417.1		1,335.0
Derivative [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, Gross Unrealized Gains	9.8	[1]	6.5	[1]
Available-for-sale Securities, Gross Unrealized Losses	2.4	[1]	2.2	[1]
Available-for-sale Securities, Amortized Cost Basis	10.6	[1]	11.6	[1]
Available-for-sale Securities, Fair Value Disclosure	18.0	[1]	15.9	[1]
Commercial Paper [Member]
Schedule of Available-for-sale Securities [Line Items]
Cash and Cash Equivalents, at Carrying Value	315.4	[2]	297.9	[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	315.4	[2]	297.9	[2]
Money Market Funds [Member]
Schedule of Available-for-sale Securities [Line Items]
Cash and Cash Equivalents, at Carrying Value	44.1	[2]	62.1	[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	44.1	[2]	62.1	[2]
Bank Time Deposits [Member]
Schedule of Available-for-sale Securities [Line Items]
Cash and Cash Equivalents, at Carrying Value	239.4	[2]	493.6	[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	239.4	[2]	493.6	[2]
Level 1 [Member]
Schedule of Available-for-sale Securities [Line Items]
Derivative, Fair Value, Net	0		0
Fair Value, Assets Measured on Recurring Basis	494.7		340.6
Level 1 [Member] | Commercial Paper [Member]
Schedule of Available-for-sale Securities [Line Items]
Cash and Cash Equivalents, Fair Value Disclosure	0		0
Level 1 [Member] | Money Market Funds [Member]
Schedule of Available-for-sale Securities [Line Items]
Cash and Cash Equivalents, Fair Value Disclosure	0		0
Level 1 [Member] | Bank Time Deposits [Member]
Schedule of Available-for-sale Securities [Line Items]
Cash and Cash Equivalents, Fair Value Disclosure	16.0		11.3
Level 2 [Member]
Schedule of Available-for-sale Securities [Line Items]
Derivative, Fair Value, Net	8.9		9.7
Fair Value, Assets Measured on Recurring Basis	895.5		965.7
Level 2 [Member] | Commercial Paper [Member]
Schedule of Available-for-sale Securities [Line Items]
Cash and Cash Equivalents, Fair Value Disclosure	315.4		297.9
Level 2 [Member] | Money Market Funds [Member]
Schedule of Available-for-sale Securities [Line Items]
Cash and Cash Equivalents, Fair Value Disclosure	44.1		62.1
Level 2 [Member] | Bank Time Deposits [Member]
Schedule of Available-for-sale Securities [Line Items]
Cash and Cash Equivalents, Fair Value Disclosure	223.4		482.3
Level 3 [Member]
Schedule of Available-for-sale Securities [Line Items]
Derivative, Fair Value, Net	9.1		6.2
Fair Value, Assets Measured on Recurring Basis	26.9		28.7
Level 3 [Member] | Commercial Paper [Member]
Schedule of Available-for-sale Securities [Line Items]
Cash and Cash Equivalents, Fair Value Disclosure	0		0
Level 3 [Member] | Money Market Funds [Member]
Schedule of Available-for-sale Securities [Line Items]
Cash and Cash Equivalents, Fair Value Disclosure	0		0
Level 3 [Member] | Bank Time Deposits [Member]
Schedule of Available-for-sale Securities [Line Items]
Cash and Cash Equivalents, Fair Value Disclosure	0		0
Other Long-term Investments [Member] | US Treasury Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, Gross Unrealized Gains	0.2		0.2
Available-for-sale Securities, Gross Unrealized Losses	0		0
Available-for-sale Securities, Amortized Cost Basis	87.9		23.6
Available-for-sale Securities, Fair Value Disclosure	88.1		23.8
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	0.3		0.2
Available-for-sale Securities, Gross Unrealized Losses	0		0
Available-for-sale Securities, Amortized Cost Basis	53.2		51.4
Available-for-sale Securities, Fair Value Disclosure	53.5		51.6
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	0.1		0
Available-for-sale Securities, Gross Unrealized Losses	0		0
Available-for-sale Securities, Amortized Cost Basis	14.5		4.6
Available-for-sale Securities, Fair Value Disclosure	14.6		4.6
Other Long-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	2.0
Available-for-sale Securities, Fair Value Disclosure	2.0
Other Long-term Investments [Member] | Corporate Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, Gross Unrealized Gains	1.3		1.0
Available-for-sale Securities, Gross Unrealized Losses	0		0.2
Available-for-sale Securities, Amortized Cost Basis	122.4		107.8
Available-for-sale Securities, Fair Value Disclosure	123.7		108.6
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		0
Available-for-sale Securities, Gross Unrealized Losses	0		0
Available-for-sale Securities, Amortized Cost Basis	4.2		4.2
Available-for-sale Securities, Fair Value Disclosure	4.2		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	88.1		23.8
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	53.5		51.6
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	14.6		4.6
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
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	123.7		108.6
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		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
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
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
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	2.0
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
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		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
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
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
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
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
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		4.2
Short-term Investments [Member]
Schedule of Available-for-sale Securities [Line Items]
Trading Securities	32.5		29.8
Trading Securities, Unrealized Holding Gain	2.3		1.8
Trading Securities, Unrealized Holding Loss	0.1		0.1
Trading Securities, Fair Value Disclosure	34.7		31.5
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
Available-for-sale Securities, Gross Unrealized Losses			0
Available-for-sale Securities, Amortized Cost Basis			143.7
Available-for-sale Securities, Fair Value Disclosure			143.8
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	178.5		5.2
Available-for-sale Securities, Fair Value Disclosure	178.5		5.2
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
Available-for-sale Securities, Gross Unrealized Losses	0
Available-for-sale Securities, Amortized Cost Basis	164.0
Available-for-sale Securities, Fair Value Disclosure	164.1
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	46.7		30.7
Available-for-sale Securities, Fair Value Disclosure	46.7		30.7
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	73.0		38.2
Available-for-sale Securities, Fair Value Disclosure	73.0		38.2
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	3.2		4.7
Available-for-sale Securities, Fair Value Disclosure	3.2		4.7
Short-term Investments [Member] | Other [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	0.3		0.3
Available-for-sale Securities, Fair Value Disclosure	0.3		0.3
Short-term Investments [Member] | Level 1 [Member]
Schedule of Available-for-sale Securities [Line Items]
Trading Securities, Fair Value Disclosure	34.7		31.5
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			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
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	40.9
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	46.7		30.7
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	73.0		38.2
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	3.2		4.7
Short-term Investments [Member] | Level 1 [Member] | Other [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, Fair Value Disclosure	0.3		0.3
Short-term Investments [Member] | Level 2 [Member]
Schedule of Available-for-sale Securities [Line Items]
Trading Securities, Fair Value Disclosure	0		0
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			108.5
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	178.5		5.2
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	123.2
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
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
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
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		0
Short-term Investments [Member] | Level 3 [Member]
Schedule of Available-for-sale Securities [Line Items]
Trading Securities, Fair Value Disclosure	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
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
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
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
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
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
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		0
Other Assets [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, Gross Unrealized Gains	0	[3]	0	[3]
Available-for-sale Securities, Gross Unrealized Losses	2.3	[3]	0	[3]
Available-for-sale Securities, Amortized Cost Basis	15.9	[3]	18.3	[3]
Available-for-sale Securities, Fair Value Disclosure	13.6	[3]	18.3	[3]
Other Assets [Member] | Level 1 [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, Fair Value Disclosure			0
Derivative, Fair Value, Net	0
Other Assets [Member] | Level 2 [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, Fair Value Disclosure			0
Derivative, Fair Value, Net	0
Other Assets [Member] | Level 3 [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, Fair Value Disclosure			18.3
Derivative, Fair Value, Net	$ 13.6

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