Stockholders' Equity (Narrative) (Details) (USD $) In Millions, except Share data, unless otherwise specified	0 Months Ended		3 Months Ended		9 Months Ended		30 Months Ended	69 Months Ended		3 Months Ended
	Jun. 11, 2010	Jun. 30, 2004	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012 employee_groups	Sep. 30, 2011	Jan. 01, 2007	Sep. 30, 2012	Sep. 30, 2012 Two Thousand And Eleven Stock Plan [Member]	Mar. 31, 2012 Two Thousand And Two Stock Plan [Member]
Components of Stockholders' Equity [Line Items]
Common Stock, Capital Shares Reserved for Future Issuance									4,500,000
Shares reserved for future grants expired					1,160,721					1,200,000
Total intrinsic value of options exercised			$ 0.4	$ 32.2	$ 13.2	$ 125.6
Cash received from option exercised			0.3	4.4	2.1	18.6
Exercise period after employment termination		3 months					1 year
Full exercise period								10 years
Number of employee groups					2
Weighted-average fair value of employee stock options granted per share			$ 32.57	$ 137.90	$ 42.58	$ 127.41
Stock repurchase plan, authorized amount	300.0
Stock repurchase program, remaining authorized repurchase amount					$ 41.0