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Derivatives and Hedging (Details)
Dec. 31, 2014
Future Contract [Member] | Exchange Traded [Member]  
Derivative [Line Items]  
Percentage of total investments (in hundredths) 84.14%dwsf_PercentageOfTotalInvestments
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Forward Contracts [Member] | Off-Exchange-Traded [Member]  
Derivative [Line Items]  
Percentage of total investments (in hundredths) 15.86%dwsf_PercentageOfTotalInvestments
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Morgan Stanley Smith Barney Spectrum Currency and Commodity L.P. [Member] | Forward Contracts [Member] | Off-Exchange-Traded [Member]  
Derivative [Line Items]  
Percentage of total investments (in hundredths) 100.00%dwsf_PercentageOfTotalInvestments
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Morgan Stanley Smith Barney Spectrum Strategic L.P. [Member] | Future Contract [Member] | Exchange Traded [Member]  
Derivative [Line Items]  
Percentage of total investments (in hundredths) 100.00%dwsf_PercentageOfTotalInvestments
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Morgan Stanley Smith Barney Spectrum Technical L.P. [Member] | Future Contract [Member] | Exchange Traded [Member]  
Derivative [Line Items]  
Percentage of total investments (in hundredths) 74.64%dwsf_PercentageOfTotalInvestments
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Morgan Stanley Smith Barney Spectrum Technical L.P. [Member] | Forward Contracts [Member] | Off-Exchange-Traded [Member]  
Derivative [Line Items]  
Percentage of total investments (in hundredths) 25.36%dwsf_PercentageOfTotalInvestments
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