Financial Instruments (Details Textual) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2011 Investment	Dec. 31, 2010 Investment	Dec. 31, 2009 Investment
Financial Instruments (Textual) [Abstract]
Federal Deposit Insurance Corporation guaranteed senior notes issued under the Temporary Liquidity Guarantee Program	$ 214.0	$ 163.5
Original maturities of commercial paper and short-term debt securities	less than 90 days
Average maturity of marketable securities, months	14 months	11 months
Sale of strategic investments	40.6	1.8	5.9
Number of strategic investments sold	4	1	2
Gain (loss) from sale of strategic equity investments	13.5		3.0
Impairment charges of our publicly-held strategic investments and for declines in value of funds that were determined to be other than temporary	11.5	21.3	10.6
Other- than-temporary impairment of publicly- held strategic investment		21.3	7.0
Impairment charges of our publicly-held strategic investments and for declines in value of funds recorded under cost method	11.5
Other-than-temporary impairment of available-for-sale securities primarily related to marketable debt securities			3.6
Strategic investments [Member]
Schedule of Available-for-sale Securities [Line Items]
Cost basis of equity securities of certain privately-owned companies and venture capital funds	$ 39.2	$ 35.0