Condensed Statements of Financial Condition (USD $)	Mar. 31, 2013	Dec. 31, 2012
Assets
Cash and cash equivalents (Notes 2 and 5)	$ 852,292,055	$ 1,100,510,722
Equity in UBS Securities LLC trading accounts:
Cash and cash equivalents	108,363,543	144,803,499
Unrealized gain (loss) on open commodity futures contracts	33,713,180	(14,596,843)
Unrealized gain (loss) on open swap contracts	4,084,315	(3,470,939)
Receivable for units sold	37,445,796	19,007,766
Dividend receivable	11,976	16,356
Other assets	81,714	11,953
Total assets	1,035,992,579	1,246,282,514
Liabilities and Partners' Capital
Payable for units redeemed	96,988,828	57,644,550
Professional fees payable	653,244	1,602,883
General Partner management fees payable (Note 3)	514,685	585,420
Brokerage commissions payable	77,750	122,250
Interest payable	153	153
Other liabilities	47,647	54,602
Total liabilities	98,282,307	60,009,858
Commitments and Contingencies (Notes 3, 4 and 5)
Partners' Capital
General Partner	0	0
Limited Partners	937,710,272	1,186,272,656
Total Partners' Capital	937,710,272	1,186,272,656
Total liabilities and partners' capital	$ 1,035,992,579	$ 1,246,282,514
Limited Partners' units outstanding	42,766,476	62,866,476
Net asset value per unit	$ 21.93	$ 18.87
Market value per unit	$ 21.88	$ 18.90