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Summary of Significant Accounting Policies (Foreign Currency Exchange) (Details) (USD $) In Millions, unless otherwise specified | Dec. 31, 2013 | Dec. 31, 2012 | Dec. 31, 2011
--- | --- | --- | ---
Significant Transactions |  |  |
Net unrealized foreign currency translation gains | $ 88.4 | $ 85.7 |
SEK |  |  |
Significant Transactions |  |  |
Foreign currency exchange rate | 6.4339 | 6.4973 | 6.8645
GBP |  |  |
Significant Transactions |  |  |
Foreign currency exchange rate | 0.6044 | 0.6154 | 0.6434
Canada, Dollars |  |  |
Significant Transactions |  |  |
Foreign currency exchange rate | 1.0625 | 0.9955 | 1.0193

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