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Investment Securities (Restrictions on Redemption Frequency and Advance Notice Requirements) (Details) $ in Millions | Sep. 30, 2017 USD ($)
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Schedule of Trading Securities and Other Trading Assets [Line Items] |
Outstanding redemptions | $ 19.1
Semi-annual | Hedge funds |
Schedule of Trading Securities and Other Trading Assets [Line Items] |
Other long-term investments | 73.8
Semi-annual | 30-59 days notice | Hedge funds |
Schedule of Trading Securities and Other Trading Assets [Line Items] |
Other long-term investments | 54.7
Semi-annual | 60-89 days notice | Hedge funds |
Schedule of Trading Securities and Other Trading Assets [Line Items] |
Other long-term investments | $ 19.1
September 2018 | Hedge funds |
Schedule of Trading Securities and Other Trading Assets [Line Items] |
Number of hedge funds | 1
Other long-term investments | $ 54.7

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