Financial Instruments (Narrative) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended			3 Months Ended	12 Months Ended		3 Months Ended	12 Months Ended
	Mar. 31, 2012	Dec. 31, 2011	Sep. 30, 2008 Senior Notes Due In Two Thousand Thirteen And Eighteen [Member]	Mar. 31, 2012 Senior Notes Due In Two Thousand Thirteen And Eighteen [Member] Third Quarter 2008 Interest Rate Locks [Member]	Dec. 31, 2011 Senior Notes Due In Two Thousand Thirteen And Eighteen [Member] Third Quarter 2008 Interest Rate Locks [Member]	Mar. 31, 2005 Senior Notes Due In Two Thousand Fifteen [Member]	Mar. 31, 2012 Senior Notes Due In Two Thousand Fifteen [Member] March 2005 Interest Rate Locks [Member]	Dec. 31, 2011 Senior Notes Due In Two Thousand Fifteen [Member] March 2005 Interest Rate Locks [Member]	Mar. 31, 2012 Designated as Hedging Instrument [Member]	Dec. 31, 2011 Designated as Hedging Instrument [Member]
Notional amounts of currency derivatives	$ 1,661.2	$ 1,818.5
Accumulated other comprehensive income (loss)	(388.6)	(553.6)							(2.0)	2.3
Deferred gain/loss, net of tax, included in accumulated other comprehensive income (AOCI) related to the fair value of the Company's currency derivatives designated as accounting hedges	(388.6)	(553.6)							(2.0)	2.3
Currency derivatives expected to be reclassified into earnings over the next twelve months	(2.0)
Approximate maximum term of currency derivatives, in months	12
Principal amount of notes			1,400.0			300.0
Deferred (loss) remaining in AOCI related to the interest rate locks				(8.5)	(9.0)		(4.0)	(4.3)
Amount expected to be reclassified into interest expense over the next twelve months				$ 1.8			$ 1.2