Funds Withheld Receivables Other Than Temporary Impairment, Credit Losses Recognized in Earnings (Details) - USD ($) $ in Millions	12 Months Ended
Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2014
Schedule of Available-for-sale Securities [Line Items]
Other than Temporary Impairment Losses, Investments, Portion Recognized in Earnings, Net, Available-for-sale Securities	$ 7.4	$ 2.3	$ 3.0
Corporate Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Other than Temporary Impairment Losses, Investments, Portion Recognized in Earnings, Net	7.4	2.2	3.0
Mortgage Backed Securities, Other [Member]
Schedule of Available-for-sale Securities [Line Items]
Other than Temporary Impairment Losses, Investments, Portion Recognized in Earnings, Net	$ 0.0	$ 0.1	$ 0.0

The amount of other than temporary impairment (OTTI) losses on equity securities, OTTI related to credit losses on debt securities, and OTTI losses on debt securities when the entity intends to sell the securities or it is more likely than not that the entity will be required to sell the securities before recovery of its amortized cost basis. Additionally, this item includes OTTI losses recognized during the period on investments accounted for under the cost method of accounting.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 8B
-URI http://asc.fasb.org/extlink&oid=73527792&loc=SL6284393-111563

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- Definition

The amount of other than temporary impairment losses on investments in debt and equity securities categorized as Available-for-sale which have been recognized in earnings during the period. Such impairment losses consist of other than temporary impairments (OTTI) on equity securities, credit losses on investments in debt securities, and when the entity intends to sell an impaired debt security or it is more likely than not that the entity will be required to sell the impaired debt security before recovery of its amortized cost basis.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=73527792&loc=d3e27161-111563

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- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

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