Entity Central Index Key Stockholders equity period increase decrease due to share transactions. Stock issued during period shares period increase decrease due to share transactions. Financial instruments owned exchange traded fund. Financial instruments owned money market mutual fund at fair value. Document and entity information. Document And Entity Information [Abstract] Document Type Document Type Amendment Flag Amendment Flag Document Period End Date Document Period End Date Document Fiscal Year Focus Document Fiscal Year Focus Document Fiscal Period Focus Document Fiscal Period Focus Trading Symbol Trading Symbol Entity Registrant Name Entity Registrant Name Entity Central Index Key Current Fiscal Year End Date Current Fiscal Year End Date Entity Filer Category Entity Filer Category Entity Small Business Entity Small Business Entity Emerging Growth Company Entity Emerging Growth Company Entity Common Stock, Shares Outstanding Entity Common Stock Shares Outstanding Investment owned unrecognized unrealized appreciation reclassed. Other investments liabilities abstract. Payable to clearing organizations. Investment Owned Unrecognized Unrealized Depreciation reclassed. Payable due to custodian. Market value per share. Statement Of Financial Position [Abstract] Assets Assets [Abstract] United States Treasury Obligations, at value (cost $1,447,642,314 and $1,614,486,381, respectively) Financial Instruments Owned U S Government And Agency Obligations At Fair Value Affiliated investments, at value (cost $319,322,279 and $394,929,293, respectively) Investments In And Advances To Affiliates At Fair Value Other investments: Other Investments [Abstract] Unrealized appreciation on LME Commodity Futures Contracts Investment Owned Unrecognized Unrealized Appreciation Reclassed Receivable for: Nontrade Receivables Unclassified [Abstract] Dividends from affiliates Dividends Receivable Other receivables Other Receivables Total assets Assets Liabilities Liabilities [Abstract] Other investments: Other Investments Liabilities [Abstract] Variation margin payable- Commodity Futures Contracts Payable To Clearing Organizations LME Commodity Futures Contracts payable Trading Liabilities Unrealized depreciation on LME Commodity Futures Contracts Investment Owned Unrecognized Unrealized Depreciation Reclassed Payable for: Payables To Broker Dealers And Clearing Organizations [Abstract] Due to custodian Payable Due To Custodian Management fees Due To Related Parties Current And Noncurrent Brokerage commissions and fees Commissions Payable To Broker Dealers And Clearing Organizations Total liabilities Liabilities Commitments and Contingencies (Note 10) Commitments And Contingencies Equity Partners Capital [Abstract] Shareholder's equity—General Shares General Partners Capital Account Shareholders' equity—Shares Limited Partners Capital Account Total shareholders' equity Stockholders Equity Total liabilities and equity Liabilities And Stockholders Equity General Shares outstanding General Partners Capital Account Units Outstanding Shares outstanding Limited Partners Capital Account Units Outstanding Net asset value per share Net Asset Value Per Share Market value per share Market Value Per Share Investments in and advances to affiliates at cost. Statement [Table] Statement [Table] Consolidated Entities Consolidated Entities [Axis] Consolidated Entities Consolidated Entities [Domain] Affiliated Investments [Member] Affiliated Entity [Member] Investment Type Investment Type [Axis] Investments Investment Type Categorization [Member] US Treasury Bill Securities [Member] U S Treasury Bill Securities [Member] Statement [Line Items] Statement [Line Items] Investments in Securities, cost Investment Owned At Cost Affiliated Investments, at Cost Investments In And Advances To Affiliates At Cost Schedule Of Investments [Abstract] Schedule Of Investments [Table] Schedule Of Investments [Table] Member stands for U.S. Treasury Bills, 2.465% due April 4, 2019. U.S. Treasury Bills, 2.465% due April 4, 2019 [Member] U S Treasury Bills Two Point Four Six Five Percentage Due April Four Two Thousand Nineteen [Member] US treasury bills two point four seven zero percentage due April twenty three two thousand nineteen. U.S. Treasury Bills, 2.470% due April 23, 2019 [Member] U S Treasury Bills Two Point Four Seven Zero Percentage Due April Twenty Three Two Thousand Nineteen [Member] US treasury bills two point three seven five percentage due may two two thousand nineteen. U.S. Treasury Bills, 2.375% due May 2, 2019 [Member] U S Treasury Bills Two Point Three Seven Five Percentage Due May Two Two Thousand Nineteen [Member] US treasury bills two point four seven zero percentage due July eleven thousand nineteen. U.S. Treasury Bills, 2.470% due July 11, 2019 [Member] U S Treasury Bills Two Point Four Seven Zero Percentage Due July Eleven Thousand Nineteen [Member] United States Treasury Obligations [Member] U S Treasury And Government [Member] Exchange-Traded Fund [Member] Exchange Traded Funds [Member] Money Market Mutual Fund - Invesco Premier U.S. Government Money Portfolio - Institutional Class [Member] Money Market Funds [Member] Member stands for U.S. Treasury Bills, 2.175% due January 3, 2019. U.S. Treasury Bills, 2.175% due January 3, 2019 [Member] U S Treasury Bills Two Point One Seven Five Percentage Due January Three Two Thousand Nineteen [Member] Member stands for US Treasury Bills, 2.370% due February 28, 2019. U.S. Treasury Bills, 2.370% due February 28, 2019 [Member] U S Treasury Bills Two Point Three Seven Zero Percentage Due February Twenty Eight Two Thousand Nineteen [Member] Member stands for U.S. Treasury Bills, 2.430% due May 2, 2019. U.S. Treasury Bills, 2.430% due May 2, 2019 [Member] U S Treasury Bills Two Point Four Three Zero Percentage Due May Two Two Thousand Nineteen [Member] Schedule of Investments [Line Items] Schedule Of Investments [Line Items] Percentage of Shareholders' Equity Investment Owned Percent Of Net Assets United States Treasury Obligations, Value United States Treasury Obligations, Principal Value Investment Owned Underlying Face Amount At Market Value Affiliated Investments, Value Affiliated Investments, Shares Investments In And Advances To Affiliates Balance Shares Investments in Securities, Value Investment Owned At Fair Value Investment Interest Rate Investment Interest Rate Investment Maturity Date Investment Maturity Date1 Investments in Securities, Cost Restricted for maintenance margin Good Faith And Margin Deposits With Broker Dealers Futures [Member] Future [Member] Position Position [Axis] Position Position [Domain] Long [Member] Long [Member] Investment Holding Investment Holding [Axis] Investment Holding Investment Holding [Domain] CBOT [Member] C B T S CME SWAPS MARKETS (COMEX) [Member] C E C S ICE FUTURES EUROPE [Member] I F E U LME CLEAR [Member] L M E C ICE FUTURES U.S. [Member] I F U S CME SWAPS MARKETS (NYMEX) [Member] N Y M S Investment Secondary Categorization Investment Secondary Categorization [Axis] Investments by Secondary Categorization Investments By Secondary Categorization [Domain] Corn. Corn [Member] Corn [Member] Soybean. Soybean [Member] Soybean [Member] Wheat commodities. Wheat [Member] Wheat [Member] Gold [Member] Gold [Member] Silver. Silver [Member] Silver [Member] Brent crude oil. Brent Crude Oil [Member] Brent Crude Oil [Member] Aluminum. Aluminum [Member] Aluminum [Member] Copper. Copper [Member] Copper [Member] Zinc. Zinc [Member] Zinc [Member] Sugar. Sugar [Member] Sugar [Member] Natural gas. Natural Gas [Member] Natural Gas [Member] NY Harbor ULSD. NY Harbor ULSD [Member] N Y Harbor U L S D [Member] RBOB Gasoline. RBOB Gasoline [Member] R B O B Gasoline [Member] WTI crude oil. WTI Crude Oil [Member] W T I Crude Oil [Member] Commodity Futures Contracts, Number of Contracts Investment Owned Balance Contracts Commodity Futures Contracts, Expiration Date Forward Contract Indexed To Issuers Equity Settlement Date Or Dates Commodity Futures Contracts, Notional Value Commodity Futures Contracts, Value Commodity Futures Contracts, Unrealized Appreciation (Depreciation) Tax Basis Of Investments Unrealized Appreciation Depreciation Net Operating expenses net. Unrealized gain loss on affiliated investments. Investment company realized gain loss on investment. Investment company unrealized gain loss on investment. Income Statement [Abstract] Income Revenues [Abstract] Interest Income Interest Income Operating Dividends from Affiliates Dividend Income Operating Total Income Interest And Dividend Income Operating Expenses Operating Expenses [Abstract] Management Fees Investment Company General Partner Advisory Service Brokerage Commissions and Fees Floor Brokerage Exchange And Clearance Fees Interest Expense Interest Expense Total Expenses Operating Expenses Less: Waivers Investment Company Contractual Fee Waived Net Expenses Operating Expenses Net Net Investment Income (Loss) Operating Income Loss Net Realized Gain (Loss) on Investment Company Realized Gain Loss On Investment [Abstract] United States Treasury Obligations Marketable Securities Realized Gain Loss Commodity Futures Contracts Gain Loss On Sale Of Commodity Contracts Net Realized Gain (Loss) Realized Investment Gains Losses Net Change in Unrealized Gain (Loss) on Investment Company Unrealized Gain Loss On Investment [Abstract] United States Treasury Obligations Marketable Securities Unrealized Gain Loss Affiliated Investments Unrealized Gain Loss On Affiliated Investments Commodity Futures Contracts Unrealized Gain Loss On Commodity Contracts Net Change in Unrealized Gain (Loss) Unrealized Gain Loss On Investments Net Realized and Net Change in Unrealized Gain (Loss) on United States Treasury Obligations, Affiliated Investments and Commodity Futures Contracts Investment Company Realized And Unrealized Gain Loss On Investment And Foreign Currency Net Income (Loss) Net Income Loss Statement Of Stockholders Equity [Abstract] Partner Type Partner Type Of Partners Capital Account [Axis] Partner Type of Partners' Capital Account, Name Partner Type Of Partners Capital Account Name [Domain] Shares [Member] Limited Partner [Member] General Shares [Member] General Partner [Member] Balance - Value Balance - Shares Partners Capital Account Units Purchases of Shares - Value Stock Issued During Period Value New Issues Purchases of Shares - Shares Stock Issued During Period Shares New Issues Redemption of Shares - Value Stock Redeemed Or Called During Period Value Redemption of Shares - Shares Stock Redeemed Or Called During Period Shares Net Increase (Decrease) due to Share Transactions, value Stockholders Equity Period Increase Decrease Due To Share Transactions Net Increase (Decrease) due to Share Transactions, shares Stock Issued During Period Shares Period Increase Decrease Due To Share Transactions Net Income (Loss) Net Income Loss Attributable To Reporting Entity [Abstract] Net Investment Income (Loss) Net Realized Gain (Loss) on United States Treasury Obligations, Affiliated Investments and Commodity Futures Contracts Realized Gain Loss On Marketable Securities Cost Method Investments And Other Investments Net Change in Unrealized Gain (Loss) on United States Treasury Obligations, Affiliated Investments and Commodity Futures Contracts Unrealized Gain Loss On Marketable Securities Cost Method Investments And Other Investments Net Change in Shareholders' Equity, value Stockholders Equity Period Increase Decrease Net Change in Shareholders' Equity, shares Stock Issued During Period Shares Period Increase Decrease Balance - Value Balance - Shares Unrealized gain loss on marketable securities, affiliated investments and derivatives and commodity contracts. Increase (decrease) in variation margin. Increase (decrease) in payable for amount due to custodian net. Operating Cash Flows Direct Method [Abstract] Cash flows from operating activities: Net Cash Provided By Used In Operating Activities [Abstract] Net Income (Loss) Adjustments to reconcile net income (loss) to net cash provided by (used for) operating activities: Adjustments To Reconcile Net Income Loss To Cash Provided By Used In Operating Activities [Abstract] Cost of securities purchased Payments For Purchase Of Securities Operating Activities Proceeds from securities sold and matured Proceeds From Sale Of Securities Operating Activities Cost of affiliated investments purchased Payments To Acquire Investments Proceeds from affiliated investments sold Proceeds From Sale Maturity And Collections Of Investments Net accretion of discount on United States Treasury Obligations Depreciation Amortization And Accretion Net Net realized (gain) loss on United States Treasury Obligations and Affiliated Investments Net change in unrealized (gain) loss on United States Treasury Obligations, Affiliated Investments and Commodity Futures Contracts Unrealized Gain Loss On Marketable Securities Affiliated Investments And Derivatives And Commodity Contracts Change in operating assets and liabilities: Increase Decrease In Operating Capital [Abstract] Dividends from affiliates Increase Decrease In Dividends Receivable Variation margin - Commodity Futures Contracts Increase Decrease In Variation Margin LME Commodity Futures Contracts Increase Decrease In Trading Liabilities Management fees Increase Decrease In Accounts Payable Related Parties Brokerage commissions and fees Increase Decrease In Payables To Broker Dealers Other receivables Increase Decrease In Other Receivables Net cash provided by (used for) operating activities Net Cash Provided By Used In Operating Activities Cash flows from financing activities: Net Cash Provided By Used In Financing Activities [Abstract] Proceeds from purchases of Shares Proceeds From Issuance Of Common Stock Redemption of Shares Payments For Repurchase Of Common Stock Decrease in payable for amount due to custodian, net Increase Decrease In Payable For Amount Due To Custodian Net Net cash provided by (used for) financing activities Net Cash Provided By Used In Financing Activities Net change in cash Cash Period Increase Decrease Cash at beginning of period Cash Cash at end of period Supplemental disclosure of cash flow information Supplemental Cash Flow Information [Abstract] Cash paid for interest Interest Paid Net Organization Consolidation And Presentation Of Financial Statements [Abstract] Organization Organization Consolidation And Presentation Of Financial Statements Disclosure [Text Block] Accounting Policies [Abstract] Summary of Significant Accounting Policies Significant Accounting Policies [Text Block] Investments Debt And Equity Securities [Abstract] Financial Instrument Risk Investments In Debt And Marketable Equity Securities And Certain Trading Assets Disclosure [Text Block] Related Party Transactions [Abstract] Service Providers and Related Party Agreements Related Party Transactions Disclosure [Text Block] Brokers And Dealers [Abstract] Deposits with Commodity Broker and Custodian Due To And From Broker Dealers And Clearing Organizations Disclosure Fair Value Disclosures [Abstract] Additional Valuation Information Fair Value Disclosures [Text Block] Derivative Instruments And Hedging Activities Disclosure [Abstract] Derivative Instruments Derivative Instruments And Hedging Activities Disclosure [Text Block] Investments In And Advances To Affiliates Schedule Of Investments [Abstract] Investments in Affiliates Investments In And Advances To Affiliates Schedule Of Investments [Text Block] Share purchases and redemptions disclosure. Text Block [Abstract] Share Purchases and Redemptions Share Purchases And Redemptions Disclosure [Text Block] Commitments And Contingencies Disclosure [Abstract] Commitments and Contingencies Commitments And Contingencies Disclosure [Text Block] Investment Company Financial Highlights [Abstract] Financial Highlights Investment Company Financial Highlights [Text Block] Basis of Presentation Basis Of Accounting Policy Policy [Text Block] Accounting Estimates Use Of Estimates Investment valuations. Investment Valuations Investment Valuations Policy [Text Block] Investment Transactions and Investment Income Investment Policy [Text Block] Profit and loss allocations and distributions. Profit and Loss Allocations and Distributions Profit And Loss Allocations And Distributions Policy [Text Block] Routine operational administrative and other ordinary expenses policy. Routine Operational, Administrative and Other Ordinary Expenses Routine Operational Administrative And Other Ordinary Expenses Policy Policy [Text Block] Non recurring and unusual fees and expenses. Non-Recurring Fees and Expenses Non Recurring And Unusual Fees And Expenses Policy [Text Block] Brokerage Commissions and Fees Commissions Policy Income Taxes Income Tax Policy [Text Block] Commodity Futures Contracts Derivatives Policy [Text Block] Receivables and payables for contracts policy. Receivable/(Payable) For LME Contracts Receivables And Payables For Contracts Policy Policy [Text Block] Summary of the Tiered Valuation Input Levels Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Table [Text Block] Fair Value of Derivative Instruments and Effect of Derivative Instruments on Statements of Income and Expenses Schedule Of Other Derivatives Not Designated As Hedging Instruments Statements Of Financial Performance And Financial Position Location Table [Text Block] Offsetting assets and liabilities. Summary of Gross and Net Amounts of Offsetting Assets and Liabilities Offsetting Assets And Liabilities Table [Text Block] Summary of Average Monthly Notional Value of Future Contracts Outstanding Schedule Of Notional Amounts Of Outstanding Derivative Positions Table [Text Block] Summary of Transactions in, and Earnings from, Investments in Affiliates (Excluding Affiliated Money Market Funds) Investments In And Advances To Affiliates [Text Block] Schedule of Net Asset Value Per Share Investment Company Financial Highlights Table [Text Block] General shares, shares issued Treasury obligation measurement maximum maturity period. Treasury obligation measurement maximum maturity period Treasury Obligation Measurement Maximum Maturity Period Minimum number of baskets of shares that can be purchased. Number of shares issued per basket. Minimum number of Baskets that can be purchased Minimum Number Of Baskets Of Shares That Can Be Purchased Number of shares issued per basket Number Of Shares Issued Per Basket Distributed earnings Distributed Earnings Average charges paid to broker per round turn trade maximum. Average charges paid to broker per round-turn trade, maximum Average Charges Paid To Broker Per Round Turn Trade Maximum Trading assets. LME contracts payable LME contracts Trading Assets Management fee per annum of daily net assets. Fee waiver termination notice period. Management fee percentage per annum of daily NAV Management Fee Per Annum Of Daily Net Assets Fee waiver termination notice period Fee Waiver Termination Notice Period Managing owner waived fees Cash equivalents held by fund Cash Equivalents At Carrying Value Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Table] Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Table] Fair Value Hierarchy and NAV Fair Value By Fair Value Hierarchy Level [Axis] Fair Value Hierarchy and NAV Fair Value Measurements Fair Value Hierarchy [Domain] Level 1 [Member] Fair Value Inputs Level1 [Member] Level 2 [Member] Fair Value Inputs Level2 [Member] Level 3 [Member] Fair Value Inputs Level3 [Member] Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items] United States Treasury Obligations Exchange-Traded Fund Financial Instruments Owned Exchange Traded Fund Money Market Mutual Fund Financial Instruments Owned Money Market Mutual Fund At Fair Value Total Investments in Securities Commodity Futures Contracts, Appreciation Investment Owned Unrecognized Unrealized Appreciation Commodity Futures Contracts, Depreciation Investment Owned Unrecognized Unrealized Depreciation Commodity Futures Contracts Investment Owned Unrecognized Unrealized Appreciation Depreciation Net Total Investments Financial Instruments Owned At Fair Value Fair Values Derivatives Balance Sheet Location By Derivative Contract Type By Hedging Designation [Table] Fair Values Derivatives Balance Sheet Location By Derivative Contract Type By Hedging Designation [Table] Derivative Instrument Derivative Instrument Risk [Axis] Derivative Contract Derivative Contract Type [Domain] Commodity Futures Contract [Member] Commodity Contract [Member] Hedging Designation Hedging Designation [Axis] Hedging Designation Hedging Designation [Domain] Not Designated as Hedging Instrument [Member] Nondesignated [Member] Derivatives, Fair Value [Line Items] Derivatives Fair Value [Line Items] Assets Derivative Fair Value Of Derivative Asset Liabilities Derivative Fair Value Of Derivative Liability Offsetting [Abstract] Offsetting assets and liabilities. Offsetting Assets And Liabilities [Table] Offsetting Assets And Liabilities [Table] Offsetting Assets And Liabilities [Table] Counterparty Name Counterparty Name [Axis] Counterparty Name Repurchase Agreement Counterparty Name [Domain] Morgan Stanley Co. LLC. Morgan Stanley & Co. LLC [Member] Morgan Stanley And Co L L C [Member] Offsetting Assets And Liabilities [Line Items] Offsetting Assets And Liabilities [Line Items] Financial Derivative Assets, Futures Contracts Financial Derivative Liabilities, Futures Contracts Net value of derivatives Derivative Fair Value Of Derivative Asset Amount Not Offset Against Collateral Collateral (Received)/Pledged, Non-Cash Derivative Collateral Obligation To Return Securities Collateral (Received)/Pledged, Cash Derivative Collateral Obligation To Return Cash Net amount Derivative Fair Value Of Derivative Asset Amount Offset Against Collateral Derivative Instruments Gain Loss By Hedging Relationship By Income Statement Location By Derivative Instrument Risk [Table] Derivative Instruments Gain Loss By Hedging Relationship By Income Statement Location By Derivative Instrument Risk [Table] Derivative Instruments, Gain (Loss) [Line Items] Derivative Instruments Gain Loss [Line Items] Futures contracts, realized gain (loss) Futures contracts, unrealized gain (loss) Net Realized and Net Change in Unrealized Gain (Loss) Gain Loss On Investments Average notional value of derivative. Derivative [Table] Derivative [Table] Range Range [Axis] Range Range [Member] Weighted Average [Member] Weighted Average [Member] Minimum [Member] Minimum [Member] Maximum [Member] Maximum [Member] Derivative [Line Items] Derivative [Line Items] Average Notional Value Average Notional Value Of Derivative Treasury obligation measurement minimum maturity period. Investments In And Advances To Affiliates [Table] Investments In And Advances To Affiliates [Table] Investments In And Advances To Affiliates [Line Items] Investments In And Advances To Affiliates [Line Items] Treasury obligation measurement minimum maturity period Treasury Obligation Measurement Minimum Maturity Period United States Treasury Obligations, at value Invesco Treasury Collateral ETF [Member] Member stands for PowerShares treasury collateral portfolio. PowerShares Treasury Collateral Portfolio [Member] Power Shares Treasury Collateral Portfolio [Member] Beginning Value Purchases at Cost Investments In And Advances To Affiliates At Fair Value Gross Additions Proceeds from Sales Payments For Proceeds From Investments Change in Unrealized Appreciation (Depreciation) Realized Gain (Loss) Gain On Sale Of Investments Ending Value Dividend Income Investments In And Advances To Affiliates Dividend Or Interest Credited To Income Equity [Abstract] Minimum number of baskets of shares that can be redeemed. Minimum number of Baskets that can be redeemed Minimum Number Of Baskets Of Shares That Can Be Redeemed Average net assets to expenses prior to waivers. Return at market value. Earnings Per Share [Abstract] Net Asset Value Net asset value per Share, beginning of period Net realized and change in unrealized gain (loss) on United States Treasury Obligations, Affiliated Investments and Commodity Futures Contracts Investment Company Gain Loss On Investment Per Share Net investment income (loss) Investment Company Investment Income Loss Per Share Net income (loss) Investment Company Investment Income Loss From Operations Per Share Net asset value per Share, end of period Market value per Share, beginning of period Market value per Share, end of period Ratio to average Net Assets Investment Company Financial Ratios [Abstract] Net investment income (loss) Investment Company Investment Income Loss Ratio Expenses, after waivers Investment Company Expense Ratio Including Voluntary Fee Waiver Expenses, prior to waivers Average Net Assets To Expenses Prior To Waivers Total Return, at net asset value Investment Company Total Return Total Return, at market value Return At Market Value