Financial Highlights - Changes in Net Asset Value Per Unit (Detail)	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Financial Highlights [Line Items]
Net realized and unrealized gains (losses)	(40.00)	564.90	(606.96)
Interest income allocated from Master	4.20	2.32	6.76
Expenses and allocation to Special Limited Partner	(217.03)	(215.14)	(224.08)
Increase (decrease) for the year	(252.83)	352.08	(824.28)
Net asset value per unit, beginning of year	10,524.14	10,172.06	10,996.34
Net asset value per unit, end of year	10,271.31	10,524.14	10,172.06
Special Limited Partner [Member]
Financial Highlights [Line Items]
Net investment income (loss)	(3.80%)	(3.40%)	(3.70%)
Allocation to Special Limited Partner
Net investment income (loss) before allocation to Special Limited Partner	(3.80%)	(3.40%)	(3.70%)
Operating expenses	3.80%	3.40%	3.70%
Allocation to Special Limited Partner
Total expenses and allocation to Special Limited Partner	3.80%	3.40%	3.70%
Total return before allocation to Special Limited Partner	(2.40%)	3.50%	(7.50%)
Allocation to Special Limited Partner
Total return after allocation to Special Limited Partner	(2.40%)	3.50%	(7.50%)