Summary of Significant Accounting Policies (Details) (USD $) In Millions, unless otherwise specified	6 Months Ended
	Jun. 30, 2014
United States of America, Dollars
Summary of Significant Accounting Policies (Details) [Line Items]
Interest Earned on Trust's Average Daily Balance on Deposit	For U.S. dollar deposits, 100% of interest earned on the Trust's assets, calculated by the average four-week Treasury bill rate, is paid to the Trust.
Percentage of Interest-bearing Domestic Deposits to Deposits	100.00%
Foreign Currencies [Member]
Summary of Significant Accounting Policies (Details) [Line Items]
Interest Earned on Trust's Average Daily Balance on Deposit	For non-U.S. dollar deposits, the current rate of interest is equal to a rate of one-month LIBOR less 100 basis points.
Maximum [Member]
Summary of Significant Accounting Policies (Details) [Line Items]
Offering Costs as Percentage of Month-end Net Asset Value	0.50%
Held by Wells Fargo Bank N.A. [Member]
Summary of Significant Accounting Policies (Details) [Line Items]
Investments and Cash	$ 1.6