CONSOLIDATED STATEMENTS OF CASH FLOWS (USD $) In Millions, unless otherwise specified	12 Months Ended
	Jan. 31, 2012	Jan. 31, 2011	Jan. 31, 2010
Operating activities:
Net income	$ 285.3	$ 212.0	$ 58.0
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	115.5	105.4	111.5
Stock-based compensation expense	108.8	80.7	93.6
Excess tax benefits from stock-based compensation	(31.5)	0	0
Impairment of goodwill	0	0	21.0
Restructuring (benefits) charges, net	(1.3)	10.8	48.2
Changes in operating assets and liabilities, net of business combinations:
Accounts receivable	(71.8)	(40.7)	37.3
Deferred income taxes	(33.8)	(2.1)	(13.5)
Prepaid expenses and other current assets	17.7	(12.9)	4.4
Accounts payable and accrued liabilities	2.6	83.7	(80.3)
Deferred revenue	129.6	71.5	(34.0)
Accrued income taxes	52.4	32.4	0.6
Net cash provided by operating activities	573.5	540.8	246.8
Investing activities:
Purchases of marketable securities	(614.2)	(507.2)	(568.9)
Sales of marketable securities	149.5	135.3	26.4
Maturities of marketable securities	409.6	275.4	328.7
Acquisitions, net of cash acquired	(221.7)	(13.5)	(26.1)
Capital expenditures	(63.0)	(28.3)	(31.7)
Other Investing Activites	(30.5)	(4.0)	(11.4)
Net cash used in investing activities	(370.3)	(142.3)	(283.0)
Financing activities:
Proceeds from issuance of common stock, net of issuance costs	176.1	120.9	70.0
Repurchases of common stock	(327.4)	(280.3)	(63.2)
Draws on line of credit	0	0	2.2
Repayments of line of credit	0	0	(54.3)
Excess tax benefits from stock-based compensation	31.5	0	0
Net cash used in financing activities	(119.8)	(159.4)	(45.3)
Effect of exchange rate changes on cash and cash equivalents	(1.6)	(2.7)	2.6
Net increase (decrease) in cash and cash equivalents	81.8	236.4	(78.9)
Cash and cash equivalents at beginning of fiscal year	1,075.1	838.7	917.6
Cash and cash equivalents at end of fiscal year	1,156.9	1,075.1	838.7
Supplemental Cash Flow Information [Abstract]
Net cash paid during the year for income taxes	$ 63.0	$ 32.5	$ 42.1