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Summary of Significant Accounting Policies Summary of Significant Accounting Policies (Details) $ in Millions | 6 Months Ended |
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Jun. 30, 2015 USD ($) segment | Dec. 31, 2014 USD ($)
Accounting Policies [Abstract] |  |
Interest in subsidiary (less than given percentage) | 100.00% |
Number of reportable segments | segment | 1 |
Payment terms of accounts receivable arising from product sales |  |
Minimum term for accounts receivable | 30 days |
Maximum term for accounts receivable | 90 days |
Accumulated depreciation | $ 1,274.2 | $ 1,186.4

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