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Debt (Narrative) (Details) - Jun. 30, 2015 - USD ($) $ in Millions | Total | Total
--- | --- | ---
Debt [Line Items] |  |
Commercial paper, long-term | $ 111.2 | $ 111.2
Senior Debentures [Member] | 3.3% senior debenture, due 2015 [Member] |  |
Debt [Line Items] |  |
Payments to retire long-term debt | $ 150.0 |
Interest rate | 3.30% | 3.30%
Commercial Paper [Member] |  |
Debt [Line Items] |  |
Interest rate | 0.50% | 0.50%
Weighted average remaining maturity, long-term debt (in days) |  | 6 days

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