Financial Highlights (Details) (USD $)	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Class 0 Units [Member]
Per unit operating performance [Abstract]
Net asset value per unit, beginning balance (in dollars per units)	$ 115.00	$ 121.13	$ 127.72	$ 114.88
Net income (loss) [Abstract]
Net investment loss (in dollars per unit)	$ (0.81)	$ (0.76)	$ (2.32)	$ (2.50)
Net gain (loss) on investments (in dollars per unit)	$ 17.42	$ (3.67)	$ 6.21	$ 4.32
Net (loss) income (in dollars per unit)	$ 16.61	$ (4.43)	$ 3.89	$ 1.82
Net asset value per unit, ending balance (in dollars per unit)	$ 131.61	$ 116.70	$ 131.61	$ 116.70
Ratios to average members' capital and total return [Abstract]
Total return before Incentive Allocation (in hundredths)	14.44%	(3.66%)	3.05%	1.58%
Incentive Allocation (in hundredths)	0.00%	0.00%	0.00%	0.00%
Total return after Incentive Allocation (in hundredths)	14.44%	(3.66%)	3.05%	1.58%
Net investment loss before Incentive Allocation (in hundredths)	(0.68%)	(0.63%)	(1.95%)	(2.11%)
Incentive Allocation (in hundredths)	0.00%	0.00%	0.00%	0.00%
Net investment loss after Incentive Allocation (in hundredths)	(0.68%)	(0.63%)	(1.95%)	(2.11%)
Total expenses before Incentive Allocation (in hundredths)	0.73%	0.69%	2.11%	2.27%
Incentive Allocation (in hundredths)	0.00%	0.00%	0.00%	0.00%
Total expenses after Incentive Allocation (in hundredths)	0.73%	0.69%	2.11%	2.27%
Class 2 Units [Member]
Per unit operating performance [Abstract]
Net asset value per unit, beginning balance (in dollars per units)	$ 87.73	$ 94.28	$ 98.41	$ 90.29
Net income (loss) [Abstract]
Net investment loss (in dollars per unit)	$ (1.08)	$ (1.06)	$ (3.15)	$ (3.33)
Net gain (loss) on investments (in dollars per unit)	$ 13.24	$ (2.85)	$ 4.63	$ 3.41
Net (loss) income (in dollars per unit)	$ 12.16	$ (3.91)	$ 1.48	$ 0.08
Net asset value per unit, ending balance (in dollars per unit)	$ 99.89	$ 90.37	$ 99.89	$ 90.37
Ratios to average members' capital and total return [Abstract]
Total return before Incentive Allocation (in hundredths)	13.86%	(4.15%)	1.50%	0.09%
Incentive Allocation (in hundredths)	0.00%	0.00%	0.00%	0.00%
Total return after Incentive Allocation (in hundredths)	13.86%	(4.15%)	1.50%	0.09%
Net investment loss before Incentive Allocation (in hundredths)	(1.19%)	(1.12%)	(3.47%)	(3.57%)
Incentive Allocation (in hundredths)	0.00%	0.00%	0.00%	0.00%
Net investment loss after Incentive Allocation (in hundredths)	(1.19%)	(1.12%)	(3.47%)	(3.57%)
Total expenses before Incentive Allocation (in hundredths)	1.24%	1.20%	3.63%	3.73%
Incentive Allocation (in hundredths)	0.00%	0.00%	0.00%	0.00%
Total expenses after Incentive Allocation (in hundredths)	1.24%	1.20%	3.63%	3.73%