Accumulated Other Comprehensive Income (Loss) Rollforward (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		6 Months Ended
	Mar. 31, 2015	Mar. 31, 2014	Mar. 31, 2015	Mar. 31, 2014	Sep. 30, 2014
Accumulated Other Comprehensive Income (Loss) [Line Items]
Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI for Sale of Securities, before Tax			$ 0
Accumulated other comprehensive loss, net	(9.3)		(9.3)		(11.6)
Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Reclassification Adjustment from AOCI, Realized upon Sale or Liquidation, before Tax			0
Other comprehensive loss	1.5	(2.8)	2.3	(3.7)
Accumulated Translation Adjustment [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated other comprehensive loss, net	(9.8)		(9.8)		(8.7)
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax			(1.1)
Other comprehensive loss			(1.1)
Accumulated Defined Benefit Plans Adjustment [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Other Comprehensive (Income) Loss, Reclassification Adjustment from AOCI, Pension and Other Postretirement Benefit Plans, Net of Tax			0
Accumulated other comprehensive loss, net	(3.5)		(3.5)		(3.5)
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax			0
Other comprehensive loss			0
Accumulated Net Unrealized Investment Gain (Loss) [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated other comprehensive loss, net	4.0		4.0		0.6
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax			3.4
Other comprehensive loss			3.4
Accumulated Other Comprehensive Loss [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated other comprehensive loss, net	(9.3)		(9.3)		(11.6)
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax			2.3
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax			0
Other comprehensive loss			$ 2.3