Investments (Unrealized Losses) (Details)	3 Months Ended
Sep. 30, 2017 USD ($) security
Asset-Backed Security
Available-for-Sale Securities and Held-to-Maturity Securities [Line Items]
Securities, other-than-temporarily impaired \| $	$ 0
Debt Securities
Available-for-Sale Securities and Held-to-Maturity Securities [Line Items]
Gross unrealized losses, number of issues	168
Gross unrealized losses, percentage of total debt	12.70%
Gross unrealized losses, market value as a percent of amortized cost	98.40%
Gross unrealized losses, number of securities with maturities of 12 months or greater	28
Gross unrealized losses, number of securities with maturities of 12 months or greater (as a percentage)	16.70%
Equity securities
Available-for-Sale Securities and Held-to-Maturity Securities [Line Items]
Gross unrealized losses, number of securities rated investment grade	26
External Credit Rating, Investment Grade \| Debt Securities
Available-for-Sale Securities and Held-to-Maturity Securities [Line Items]
Gross unrealized losses, number of securities rated investment grade	163

Available-for-Sale Securities and Held-to-Maturity Securities [Line Items]

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Available-for-sale Securities, Gross Unrealized Losses, Market Value of Bonds Percent of Amortized Cost

+ References

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Available for Sale Securities, Gross Unrealized Losses, Number of Securities

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Available for Sale Securities, Gross Unrealized Losses, Number of Securities as a Percentage of Total Debt

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Available-for-sale Securities, Gross Unrealized Losses, Number of Securities, Debt Maturities, Twelve Months or Greater

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Available-for-sale Securities, Gross Unrealized Losses, Number of Securities, Debt Maturities, Twelve Months or Greater, Percent of Total

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- Definition

Disclosure regarding factors used to determine that the impairment of securities categorized as held-to-maturity where cost exceeds fair value is not an other than temporary impairment (OTTI). This item contains disclosure of the number of investment positions in the held-to-maturity investments determined to be temporarily impaired.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 6
-Subparagraph (b)(3)
-URI http://asc.fasb.org/extlink&oid=82897076&loc=d3e27290-111563

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The amount by which the fair value of an investment in debt and equity securities categorized as Available-for-sale is less than the amortized cost basis or carrying amount of that investment at the balance sheet date and the decline in fair value is deemed to be other than temporary, before considering whether or not such amount is recognized in earnings or other comprehensive income.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 45
-Paragraph 8A
-URI http://asc.fasb.org/extlink&oid=82896770&loc=SL6284422-111562

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