Investments in Affiliates (Tables)

6 Months Ended

Jun. 30, 2018

Investments In And Advances To Affiliates Schedule Of Investments [Abstract]

Summary of Transactions in, and Earnings from, Investments in Affiliates (Excluding Affiliated Money Market Funds)

The following is a summary of the transactions in, and earnings from, investments in affiliates (excluding affiliated money market funds) for the three and six months ended June 30, 2018.

	Value 03/31/2018		Purchases at Cost		Proceeds from Sales		Change in Unrealized Appreciation (Depreciation)		Realized Gain (Loss)		Value 06/30/2018		Dividend Income
Invesco Treasury    Collateral ETF	$	250,715,232	$	—	$	—	$	1,020,132	$	—	$	251,735,364	$	—

	Value 12/31/2017		Purchases at Cost		Proceeds from Sales		Change in Unrealized Appreciation (Depreciation)		Realized Gain (Loss)		Value 06/30/2018		Dividend Income
Invesco Treasury    Collateral ETF	$	249,742,548	$	—	$	—	$	1,992,816	$	—	$	251,735,364	$	—

The following is a summary of the transactions in, and earnings from, investments in affiliates (excluding affiliated money market funds) for the three and six months ended June 30, 2017.

	Value 04/01/2017		Purchases at Cost		Proceeds from Sales		Change in Unrealized Appreciation (Depreciation)		Realized Gain (Loss)		Value 06/30/2017		Dividend Income
PowerShares Treasury    Collateral Portfolio	$	250,074,684	$	—	$	—	$	450,756	$	—	$	250,525,440	$	—

	Value 01/01/2017		Purchases at Cost		Proceeds from Sales		Change in Unrealized Appreciation (Depreciation)		Realized Gain (Loss)		Value 06/30/2017		Dividend Income
PowerShares Treasury    Collateral Portfolio	$	—	$	249,990,226	$	—	$	535,214	$	—	$	250,525,440	$	—