Condensed Consolidated Statement of Comprehensive Income (USD $) In Millions, unless otherwise specified	3 Months Ended
	Dec. 31, 2013	Dec. 31, 2012
Condensed Consolidated Statement of Other Comprehensive Income (Loss) [Abstract]
Net income	$ 2.5	$ 13.3
Other comprehensive income (loss), net of tax:
Foreign currency translation adjustment	(1.2)	(0.3)
Pension liabilities adjustment	0.1	0.4
Net unrealized gain or loss on available-for-sale securities	0.2	(0.2)
Reclassification of adjustment for gains included in net income [Abstract]
Realized gain on available-for-sale securities (included in trading gains, net)	0	(8.3)
Income tax expense from reclassification adjustments (included in income tax expense)	0	2.0
Reclassification adjustment for gains included in net income	0	(6.3)
Other comprehensive loss	(0.9)	(6.4)
Comprehensive income	$ 1.6	$ 6.9