Permanent Equity - Accumulated Other Comprehensive Income (Details) (USD $) In Millions, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012
Accumulated Other Comprehensive Income (Loss) [Line Items]
Gross amounts (after reclassification adjustments)	$ 192.9	$ 1,015.3
Intangible assets adjustments	(62.8)	(390.1)
Tax effects	(57.9)	(226.2)
Noncontrolling interest	15.5	14.2
Accumulated Other Comprehensive Income (Loss), Net of Tax	87.7	413.2
Accumulated Net Unrealized Investment Gain (Loss)
Accumulated Other Comprehensive Income (Loss) [Line Items]
Gross amounts (after reclassification adjustments)	235.7	1,059.6
Intangible assets adjustments	(63.2)	(390.5)
Tax effects	(61.1)	(234.2)
Noncontrolling interest
Accumulated Other Comprehensive Income (Loss), Net of Tax	111.4	434.9
Accumulated Other-than-Temporary Impairment
Accumulated Other Comprehensive Income (Loss) [Line Items]
Gross amounts (after reclassification adjustments)	(1.0)	(1.0)
Intangible assets adjustments	0.4	0.4
Tax effects	0.2	0.2
Noncontrolling interest
Accumulated Other Comprehensive Income (Loss), Net of Tax	(0.4)	(0.4)
Accumulated Net Gain (Loss) from Designated or Qualifying Cash Flow Hedges
Accumulated Other Comprehensive Income (Loss) [Line Items]
Gross amounts (after reclassification adjustments)	(2.6)	0.3
Intangible assets adjustments
Tax effects	0.3	(0.1)
Noncontrolling interest	0.9	(0.1)
Accumulated Other Comprehensive Income (Loss), Net of Tax	(1.4)	0.1
Accumulated Defined Benefit Plans Adjustment
Accumulated Other Comprehensive Income (Loss) [Line Items]
Gross amounts (after reclassification adjustments)	(28.9)	(39.9)
Intangible assets adjustments
Tax effects	(0.8)	4.4
Noncontrolling interest	11.9	14.2
Accumulated Other Comprehensive Income (Loss), Net of Tax	(17.8)	(21.3)
Accumulated Translation Adjustment
Accumulated Other Comprehensive Income (Loss) [Line Items]
Gross amounts (after reclassification adjustments)	(10.3)	(3.7)
Intangible assets adjustments
Tax effects	3.5	3.5
Noncontrolling interest	2.7	0.1
Accumulated Other Comprehensive Income (Loss), Net of Tax	$ (4.1)	$ (0.1)