v2.4.0.6

Significant Accounting Policies (Valuation of Investments) (Detail) (USD $)	3 Months Ended	12 Months Ended
	Mar. 31, 2013	Dec. 31, 2012
Significant Accounting Policies [Line Items]
Level III portfolio investments	$ 0	$ 0
ProShares UltraShort DJ-UBS Commodity [Member]
Significant Accounting Policies [Line Items]
Investments, fair value disclosure	2,969,893	2,952,406
ProShares UltraShort DJ-UBS Crude Oil [Member]
Significant Accounting Policies [Line Items]
Investments, fair value disclosure	134,336,722	77,409,608
ProShares UltraShort DJ-UBS Natural Gas [Member]
Significant Accounting Policies [Line Items]
Investments, fair value disclosure	17,696,463	10,451,866
ProShares UltraShort Gold [Member]
Significant Accounting Policies [Line Items]
Investments, fair value disclosure	104,909,385	92,320,494
ProShares UltraShort Silver [Member]
Significant Accounting Policies [Line Items]
Investments, fair value disclosure	105,630,051	105,554,406
ProShares Short Euro [Member]
Significant Accounting Policies [Line Items]
Investments, fair value disclosure	3,433,678	3,354,848
ProShares UltraShort Australian Dollar [Member]
Significant Accounting Policies [Line Items]
Investments, fair value disclosure	3,220,400	3,388,497
ProShares UltraShort Euro [Member]
Significant Accounting Policies [Line Items]
Investments, fair value disclosure	520,855,991	540,282,990
ProShares UltraShort Yen [Member]
Significant Accounting Policies [Line Items]
Investments, fair value disclosure	466,350,321	400,857,406
ProShares Ultra DJ-UBS Commodity [Member]
Significant Accounting Policies [Line Items]
Investments, fair value disclosure	3,465,699	5,934,683
ProShares Ultra DJ-UBS Crude Oil [Member]
Significant Accounting Policies [Line Items]
Investments, fair value disclosure	330,556,198	492,956,680
ProShares Ultra DJ-UBS Natural Gas [Member]
Significant Accounting Policies [Line Items]
Investments, fair value disclosure	67,746,797	60,496,274
ProShares Ultra Gold [Member]
Significant Accounting Policies [Line Items]
Investments, fair value disclosure	316,607,862	334,957,606
ProShares Ultra Silver [Member]
Significant Accounting Policies [Line Items]
Investments, fair value disclosure	746,826,870	745,276,660
ProShares Ultra Australian Dollar [Member]
Significant Accounting Policies [Line Items]
Investments, fair value disclosure	3,801,832	3,471,864
ProShares Ultra Euro [Member]
Significant Accounting Policies [Line Items]
Investments, fair value disclosure	4,344,924	4,634,103
ProShares Ultra Yen [Member]
Significant Accounting Policies [Line Items]
Investments, fair value disclosure	3,464,372	4,093,622
ProShares VIX Short-Term Futures ETF [Member]
Significant Accounting Policies [Line Items]
Investments, fair value disclosure	144,590,749	143,839,502
ProShares VIX Mid-Term Futures ETF [Member]
Significant Accounting Policies [Line Items]
Investments, fair value disclosure	47,826,009	78,460,456
ProShares Ultra VIX Short-Term Futures ETF [Member]
Significant Accounting Policies [Line Items]
Investments, fair value disclosure	100,047,635	99,799,256
ProShares Short VIX Short-Term Futures ETF [Member]
Significant Accounting Policies [Line Items]
Investments, fair value disclosure	48,219,559	52,299,177
Total Trust [Member]
Significant Accounting Policies [Line Items]
Investments, fair value disclosure	3,176,901,410	3,262,792,404
Level I - Quoted Prices [Member] | ProShares UltraShort DJ-UBS Commodity [Member] | Short-Term U.S. Government And Agencies [Member]
Significant Accounting Policies [Line Items]
Investments, fair value disclosure	3,062,812	2,803,904
Level I - Quoted Prices [Member] | ProShares UltraShort DJ-UBS Crude Oil [Member] | Short-Term U.S. Government And Agencies [Member]
Significant Accounting Policies [Line Items]
Investments, fair value disclosure	145,473,612	87,046,389
Level I - Quoted Prices [Member] | ProShares UltraShort DJ-UBS Crude Oil [Member] | VIX Futures Contracts [Member]
Significant Accounting Policies [Line Items]
Investments, fair value disclosure	231,524	(4,029,721)
Level I - Quoted Prices [Member] | ProShares UltraShort DJ-UBS Natural Gas [Member] | Short-Term U.S. Government And Agencies [Member]
Significant Accounting Policies [Line Items]
Investments, fair value disclosure	21,193,216	10,042,731
Level I - Quoted Prices [Member] | ProShares UltraShort DJ-UBS Natural Gas [Member] | VIX Futures Contracts [Member]
Significant Accounting Policies [Line Items]
Investments, fair value disclosure	(3,496,753)	409,135
Level I - Quoted Prices [Member] | ProShares UltraShort Gold [Member] | Short-Term U.S. Government And Agencies [Member]
Significant Accounting Policies [Line Items]
Investments, fair value disclosure	108,157,077	88,575,398
Level I - Quoted Prices [Member] | ProShares UltraShort Gold [Member] | VIX Futures Contracts [Member]
Significant Accounting Policies [Line Items]
Investments, fair value disclosure	(1,410)	15,240
Level I - Quoted Prices [Member] | ProShares UltraShort Silver [Member] | Short-Term U.S. Government And Agencies [Member]
Significant Accounting Policies [Line Items]
Investments, fair value disclosure	105,347,243	86,206,701
Level I - Quoted Prices [Member] | ProShares UltraShort Silver [Member] | VIX Futures Contracts [Member]
Significant Accounting Policies [Line Items]
Investments, fair value disclosure	27,520	40,020
Level I - Quoted Prices [Member] | ProShares Short Euro [Member] | Short-Term U.S. Government And Agencies [Member]
Significant Accounting Policies [Line Items]
Investments, fair value disclosure	3,371,965	3,409,904
Level I - Quoted Prices [Member] | ProShares Short Euro [Member] | VIX Futures Contracts [Member]
Significant Accounting Policies [Line Items]
Investments, fair value disclosure	61,713	(55,056)
Level I - Quoted Prices [Member] | ProShares UltraShort Australian Dollar [Member] | Short-Term U.S. Government And Agencies [Member]
Significant Accounting Policies [Line Items]
Investments, fair value disclosure	3,329,970	3,302,907
Level I - Quoted Prices [Member] | ProShares UltraShort Australian Dollar [Member] | VIX Futures Contracts [Member]
Significant Accounting Policies [Line Items]
Investments, fair value disclosure	(109,570)	85,590
Level I - Quoted Prices [Member] | ProShares UltraShort Euro [Member] | Short-Term U.S. Government And Agencies [Member]
Significant Accounting Policies [Line Items]
Investments, fair value disclosure	507,190,542	553,430,562
Level I - Quoted Prices [Member] | ProShares UltraShort Yen [Member] | Short-Term U.S. Government And Agencies [Member]
Significant Accounting Policies [Line Items]
Investments, fair value disclosure	463,617,695	362,743,231
Level I - Quoted Prices [Member] | ProShares Ultra DJ-UBS Commodity [Member] | Short-Term U.S. Government And Agencies [Member]
Significant Accounting Policies [Line Items]
Investments, fair value disclosure	3,350,652	6,240,951
Level I - Quoted Prices [Member] | ProShares Ultra DJ-UBS Crude Oil [Member] | Short-Term U.S. Government And Agencies [Member]
Significant Accounting Policies [Line Items]
Investments, fair value disclosure	304,000,111	437,662,650
Level I - Quoted Prices [Member] | ProShares Ultra DJ-UBS Crude Oil [Member] | VIX Futures Contracts [Member]
Significant Accounting Policies [Line Items]
Investments, fair value disclosure	1,362,516	21,960,410
Level I - Quoted Prices [Member] | ProShares Ultra DJ-UBS Natural Gas [Member] | Short-Term U.S. Government And Agencies [Member]
Significant Accounting Policies [Line Items]
Investments, fair value disclosure	53,702,179	64,313,224
Level I - Quoted Prices [Member] | ProShares Ultra DJ-UBS Natural Gas [Member] | VIX Futures Contracts [Member]
Significant Accounting Policies [Line Items]
Investments, fair value disclosure	14,044,618	(3,816,950)
Level I - Quoted Prices [Member] | ProShares Ultra Gold [Member] | Short-Term U.S. Government And Agencies [Member]
Significant Accounting Policies [Line Items]
Investments, fair value disclosure	307,384,042	350,624,904
Level I - Quoted Prices [Member] | ProShares Ultra Gold [Member] | VIX Futures Contracts [Member]
Significant Accounting Policies [Line Items]
Investments, fair value disclosure	1,380	(15,240)
Level I - Quoted Prices [Member] | ProShares Ultra Silver [Member] | Short-Term U.S. Government And Agencies [Member]
Significant Accounting Policies [Line Items]
Investments, fair value disclosure	754,961,358	891,057,386
Level I - Quoted Prices [Member] | ProShares Ultra Silver [Member] | VIX Futures Contracts [Member]
Significant Accounting Policies [Line Items]
Investments, fair value disclosure	(27,770)	(40,020)
Level I - Quoted Prices [Member] | ProShares Ultra Australian Dollar [Member] | Short-Term U.S. Government And Agencies [Member]
Significant Accounting Policies [Line Items]
Investments, fair value disclosure	3,676,902	3,570,894
Level I - Quoted Prices [Member] | ProShares Ultra Australian Dollar [Member] | VIX Futures Contracts [Member]
Significant Accounting Policies [Line Items]
Investments, fair value disclosure	124,930	(99,030)
Level I - Quoted Prices [Member] | ProShares Ultra Euro [Member] | Short-Term U.S. Government And Agencies [Member]
Significant Accounting Policies [Line Items]
Investments, fair value disclosure	4,478,920	4,546,944
Level I - Quoted Prices [Member] | ProShares Ultra Yen [Member] | Short-Term U.S. Government And Agencies [Member]
Significant Accounting Policies [Line Items]
Investments, fair value disclosure	3,534,934	4,587,918
Level I - Quoted Prices [Member] | ProShares VIX Short-Term Futures ETF [Member] | Short-Term U.S. Government And Agencies [Member]
Significant Accounting Policies [Line Items]
Investments, fair value disclosure	152,936,809	144,060,921
Level I - Quoted Prices [Member] | ProShares VIX Short-Term Futures ETF [Member] | VIX Futures Contracts [Member]
Significant Accounting Policies [Line Items]
Investments, fair value disclosure	(8,346,060)	(221,419)
Level I - Quoted Prices [Member] | ProShares VIX Mid-Term Futures ETF [Member] | Short-Term U.S. Government And Agencies [Member]
Significant Accounting Policies [Line Items]
Investments, fair value disclosure	49,702,438	79,930,866
Level I - Quoted Prices [Member] | ProShares VIX Mid-Term Futures ETF [Member] | VIX Futures Contracts [Member]
Significant Accounting Policies [Line Items]
Investments, fair value disclosure	(1,876,429)	(1,470,410)
Level I - Quoted Prices [Member] | ProShares Ultra VIX Short-Term Futures ETF [Member] | Short-Term U.S. Government And Agencies [Member]
Significant Accounting Policies [Line Items]
Investments, fair value disclosure	118,784,756	97,440,843
Level I - Quoted Prices [Member] | ProShares Ultra VIX Short-Term Futures ETF [Member] | VIX Futures Contracts [Member]
Significant Accounting Policies [Line Items]
Investments, fair value disclosure	(18,737,121)	2,057,062
Level I - Quoted Prices [Member] | ProShares Short VIX Short-Term Futures ETF [Member] | Short-Term U.S. Government And Agencies [Member]
Significant Accounting Policies [Line Items]
Investments, fair value disclosure	45,830,843	53,686,352
Level I - Quoted Prices [Member] | ProShares Short VIX Short-Term Futures ETF [Member] | VIX Futures Contracts [Member]
Significant Accounting Policies [Line Items]
Investments, fair value disclosure	2,388,716	(1,387,175)
Level I - Quoted Prices [Member] | Total Trust [Member] | Short-Term U.S. Government And Agencies [Member]
Significant Accounting Policies [Line Items]
Investments, fair value disclosure	3,163,088,076	3,335,285,580
Level I - Quoted Prices [Member] | Total Trust [Member] | VIX Futures Contracts [Member]
Significant Accounting Policies [Line Items]
Investments, fair value disclosure	(14,352,196)	13,432,436
Level II - Other Significant Observable Inputs [Member] | ProShares UltraShort DJ-UBS Commodity [Member] | Swap Agreements [Member]
Significant Accounting Policies [Line Items]
Investments, fair value disclosure	(92,919)	148,502
Level II - Other Significant Observable Inputs [Member] | ProShares UltraShort DJ-UBS Crude Oil [Member] | Swap Agreements [Member]
Significant Accounting Policies [Line Items]
Investments, fair value disclosure	(11,368,414)	(5,607,060)
Level II - Other Significant Observable Inputs [Member] | ProShares UltraShort Gold [Member] | Swap agreements or forward contracts [Member]
Significant Accounting Policies [Line Items]
Investments, fair value disclosure	(3,246,282)	3,729,856
Level II - Other Significant Observable Inputs [Member] | ProShares UltraShort Silver [Member] | Swap agreements or forward contracts [Member]
Significant Accounting Policies [Line Items]
Investments, fair value disclosure	255,288	19,307,685
Level II - Other Significant Observable Inputs [Member] | ProShares UltraShort Euro [Member] | Foreign Currency Forward Contracts [Member]
Significant Accounting Policies [Line Items]
Investments, fair value disclosure	13,665,449	(13,147,572)
Level II - Other Significant Observable Inputs [Member] | ProShares UltraShort Yen [Member] | Foreign Currency Forward Contracts [Member]
Significant Accounting Policies [Line Items]
Investments, fair value disclosure	2,732,626	38,114,175
Level II - Other Significant Observable Inputs [Member] | ProShares Ultra DJ-UBS Commodity [Member] | Swap Agreements [Member]
Significant Accounting Policies [Line Items]
Investments, fair value disclosure	115,047	(306,268)
Level II - Other Significant Observable Inputs [Member] | ProShares Ultra DJ-UBS Crude Oil [Member] | Swap Agreements [Member]
Significant Accounting Policies [Line Items]
Investments, fair value disclosure	25,193,571	33,333,620
Level II - Other Significant Observable Inputs [Member] | ProShares Ultra Gold [Member] | Swap agreements or forward contracts [Member]
Significant Accounting Policies [Line Items]
Investments, fair value disclosure	9,222,440	(15,652,058)
Level II - Other Significant Observable Inputs [Member] | ProShares Ultra Silver [Member] | Swap agreements or forward contracts [Member]
Significant Accounting Policies [Line Items]
Investments, fair value disclosure	(8,106,718)	(145,740,706)
Level II - Other Significant Observable Inputs [Member] | ProShares Ultra Euro [Member] | Foreign Currency Forward Contracts [Member]
Significant Accounting Policies [Line Items]
Investments, fair value disclosure	(133,996)	87,159
Level II - Other Significant Observable Inputs [Member] | ProShares Ultra Yen [Member] | Foreign Currency Forward Contracts [Member]
Significant Accounting Policies [Line Items]
Investments, fair value disclosure	(70,562)	(494,296)
Level II - Other Significant Observable Inputs [Member] | ProShares Ultra VIX Short-Term Futures ETF [Member] | Swap Agreements [Member]
Significant Accounting Policies [Line Items]
Investments, fair value disclosure		301,351
Level II - Other Significant Observable Inputs [Member] | Total Trust [Member] | Swap agreements or forward contracts [Member]
Significant Accounting Policies [Line Items]
Investments, fair value disclosure	(1,875,272)	(138,355,223)
Level II - Other Significant Observable Inputs [Member] | Total Trust [Member] | Foreign Currency Forward Contracts [Member]
Significant Accounting Policies [Line Items]
Investments, fair value disclosure	16,193,517	24,559,466
Level II - Other Significant Observable Inputs [Member] | Total Trust [Member] | Swap Agreements [Member]
Significant Accounting Policies [Line Items]
Investments, fair value disclosure	$ 13,847,285	$ 27,870,145

X

- Definition

Level Three Portfolio Investments For Significant Unobservable Inputs Fair Value

+ References

No definition available.

+ Details

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X

- Details

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Namespace Prefix:	ck0001415311_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

X

- Definition

This element represents the portion of the balance sheet assertion valued at fair value by the entity whether such amount is presented as a separate caption or as a parenthetical disclosure. Additionally, this element may be used in connection with the fair value disclosures required in the footnote disclosures to the financial statements. The element may be used in both the balance sheet and disclosure in the same submission. This item represents investment securities as of the balance sheet date which may include marketable securities, derivative financial instruments, and investments accounted for under the equity method.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Glossary Trading Securities

-URI http://asc.fasb.org/extlink&oid=6526789



Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 320

-SubTopic 10

-Section 25

-Paragraph 1

-URI http://asc.fasb.org/extlink&oid=7534914&loc=d3e22054-111558



Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 115

-Paragraph 13

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.



Reference 4: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 03

-Paragraph 1

-Subparagraph a, f, g

-Article 7



Reference 5: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Glossary Available-for-Sale Securities

-URI http://asc.fasb.org/extlink&oid=6505594



Reference 6: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 115

-Paragraph 12

-Subparagraph a

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.



Reference 7: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 320

-SubTopic 10

-Section 35

-Paragraph 1

-URI http://asc.fasb.org/extlink&oid=16383099&loc=d3e24584-111560

+ Details

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