Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Millions	6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014
Cash flows from operating activities:
Net income	$ 238.2	$ 331.7
Adjustments to reconcile net income to net cash provided by operating activities:
Share-based compensation expense	104.9	120.1
Depreciation, amortization, and accretion	89.0	95.6
Restructuring and other (benefit) charges	(0.5)	194.4
Deferred income taxes	23.9	(82.3)
Gain on investments, net	(0.8)	(167.0)
Gain on legal settlement, net	0.0	(120.3)
Excess tax benefits from share-based compensation	(4.3)	(8.0)
Loss on disposal of fixed assets	0.4	0.8
Changes in operating assets and liabilities, net of effects from acquisitions:
Accounts receivable, net	29.0	21.4
Prepaid expenses and other assets	(41.7)	(3.9)
Accounts payable	(13.8)	52.5
Accrued compensation	3.6	(39.5)
Income taxes payable	56.7	113.5
Other accrued liabilities	(30.7)	(62.7)
Deferred revenue	28.6	101.9
Net cash provided by operating activities	482.5	548.2
Cash flows from investing activities:
Purchases of property and equipment	(83.8)	(98.6)
Purchases of available-for-sale investments	(841.3)	(1,577.6)
Proceeds from sales of available-for-sale investments	450.9	1,504.6
Proceeds from maturities of available-for-sale investments	115.9	234.2
Purchases of trading investments	(2.5)	(2.4)
Proceeds from sales of privately-held investments	0.0	2.5
Purchases of privately-held investments	(3.2)	(5.0)
Payments for business acquisitions, net of cash and cash equivalents acquired	0.0	(27.1)
Changes in restricted cash	0.0	25.0
Net cash (used in) provided by investing activities	(364.0)	55.6
Cash flows from financing activities:
Proceeds from issuance of common stock	63.0	121.2
Purchases and retirement of common stock	(1,004.7)	(907.1)
Purchase of equity forward contract	0.0	(300.0)
Issuance of long-term debt, net	594.6	346.5
Payment for capital lease obligation	0.4	(0.4)
Customer financing arrangements	0.0	0.7
Excess tax benefits from share-based compensation	4.3	8.0
Payment of cash dividends	(79.5)	0.0
Net cash used in financing activities	(421.9)	(731.1)
Effect of foreign currency exchange rates on cash and cash equivalents	(5.9)	3.1
Net decrease in cash and cash equivalents	(309.3)	(124.2)
Cash and cash equivalents at beginning of period	1,639.6	2,284.0
Cash and cash equivalents at end of period	$ 1,330.3	$ 2,159.8