CONSOLIDATED STATEMENTS OF CASH FLOWS (USD $) In Millions, unless otherwise specified	12 Months Ended
	Jan. 31, 2013	Jan. 31, 2012	Jan. 31, 2011
Operating activities:
Net income	$ 247.4	$ 285.3	$ 212.0
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation, amortization and accretion	127.8	115.5	105.4
Stock-based compensation expense	156.3	108.8	80.7
Excess tax benefits from stock-based compensation	(12.9)	(31.5)	0
Restructuring (benefits) charges	43.9	(1.3)	10.8
Other operating activities	6.7	(0.3)	(2.0)
Changes in operating assets and liabilities, net of business combinations:
Accounts receivable	(98.1)	(71.8)	(40.7)
Deferred income taxes	(28.3)	(33.8)	(2.1)
Prepaid expenses and other current assets	0.1	17.7	(12.9)
Accounts payable and accrued liabilities	(28.3)	2.9	85.7
Deferred revenue	113.3	129.6	71.5
Accrued income taxes	31.2	52.4	32.4
Net cash provided by operating activities	559.1	573.5	540.8
Investing activities:
Purchases of marketable securities	(1,397.7)	(614.2)	(507.2)
Sales of marketable securities	332.9	149.5	135.3
Maturities of marketable securities	764.8	409.6	275.4
Acquisitions, net of cash acquired	(263.7)	(221.7)	(13.5)
Capital expenditures	(56.4)	(63.0)	(28.3)
Other Investing Activites	(27.1)	(30.5)	(4.0)
Net cash used in investing activities	(647.2)	(370.3)	(142.3)
Financing activities:
Proceeds from issuance of common stock, net of issuance costs	220.2	176.1	120.9
Repurchases of common stock	(431.2)	(327.4)	(280.3)
Draws on line of credit	110.0	0	0
Proceeds from Issuance of Long-term Debt	745.6	0	0
Repayments of line of credit	(110.0)	0	0
Excess tax benefits from stock-based compensation	12.9	31.5	0
Other financing activities	(6.1)	0	0
Net cash provided by (used in) financing activities	541.4	(119.8)	(159.4)
Effect of exchange rate changes on cash and cash equivalents	2.0	(1.6)	(2.7)
Net increase (decrease) in cash and cash equivalents	455.3	81.8	236.4
Cash and cash equivalents at beginning of fiscal year	1,156.9	1,075.1	838.7
Cash and cash equivalents at end of fiscal year	1,612.2	1,156.9	1,075.1
Supplemental Cash Flow Information [Abstract]
Interest Paid	0.4	0	0
Net cash paid during the year for income taxes	$ 59.7	$ 63.0	$ 32.5