Schedule III - Supplemental Insurance Information Schedule III - Supplemental Insurance Information (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2011
Supplementary Insurance Information [Abstract]
Other policy claims and benefits payable	$ 58.1	$ 51.5	$ 91.1
Deferred acquisition costs	463.8		340.6	169.2
Future policy benefits, losses, claims and loss expenses	3,655.5		3,556.8	3,614.8
Premium revenue	56.6	55.3	58.8
Net investment income	824.5	716.2	715.5
Benefits, claims, losses and settlement expenses	(852.7)	(777.4)	(531.8)
Amortization of deferred acquisition costs	(41.7)	(15.2)	(45.3)
Other operating expenses	$ (114.7)	$ (123.9)	$ (111.4)

Name:	us-gaap_SupplementaryInsuranceInformationAbstract
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

Amount of amortization of deferred policy acquisition costs recognized.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 16

-Article 12

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 944

-SubTopic 235

-Section S99

-Paragraph 1

-Subparagraph (SX 210.12-16)

-URI http://asc.fasb.org/extlink&oid=34713774&loc=d3e574960-122915

+ Details

Name:	us-gaap_SupplementaryInsuranceInformationAmortizationOfDeferredPolicyAcquisitionCosts
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Amount of insurance benefits, claims, losses and settlement expenses incurred.

+ References

+ Details

Name:	us-gaap_SupplementaryInsuranceInformationBenefitsClaimsLossesAndSettlementExpense
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Net amount of deferred policy acquisition costs capitalized on contracts remaining in force on the balance sheet date.

+ References

+ Details

Name:	us-gaap_SupplementaryInsuranceInformationDeferredPolicyAcquisitionCosts
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Amount of reserves for future policy claims payable and loss expenses to be incurred.

+ References

+ Details

Name:	us-gaap_SupplementaryInsuranceInformationLiabilityForFuturePolicyBenefitsLossesClaimsAndLossExpenseReserves
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount of net investment income earned.

+ References

+ Details

Name:	us-gaap_SupplementaryInsuranceInformationNetInvestmentIncome
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Amount of other operating expense incurred.

+ References

+ Details

Name:	us-gaap_SupplementaryInsuranceInformationOtherOperatingExpense
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Amount of claims and benefits payable not included within other categories.

+ References

+ Details

Name:	us-gaap_SupplementaryInsuranceInformationOtherPolicyClaimsAndBenefitsPayable
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount of premium revenue earned.

+ References

+ Details

Name:	us-gaap_SupplementaryInsuranceInformationPremiumRevenue
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration