Financial Highlights (Details) (USD $)	3 Months Ended
	Mar. 31, 2015	Mar. 31, 2014
Class 0 Units [Member]
Per unit operating performance [Abstract]
Net asset value per unit, beginning balance (in dollars per units)	$ 149.37	$ 127.72
Net income (loss): [Abstract]
Net investment loss (in dollars per unit)	$ (1.04)	$ (0.76)
Net gain (loss) on investments (in dollars per unit)	$ 11.60	$ (12.93)
Net (loss) income (in dollars per unit)	$ 10.56	$ (13.69)
Net asset value per unit, ending balance (in dollars per unit)	$ 159.93	$ 114.03
Ratios to average members' capital and total return [Abstract]
Total return before Incentive Allocation (in hundredths)	8.83%	(10.72%)
Incentive Allocation (in hundredths)	(1.76%)	0.00%
Total return after Incentive Allocation (in hundredths)	7.07%	(10.72%)
Net investment loss before Incentive Allocation (in hundredths)	(0.66%)	(0.63%)
Incentive Allocation (in hundredths)	(1.69%)	0.00%
Net investment loss after Incentive Allocation (in hundredths)	(2.35%)	(0.63%)
Total expenses before Incentive Allocation (in hundredths)	0.73%	0.68%
Incentive Allocation (in hundredths)	1.69%	0.00%
Total expenses after Incentive Allocation (in hundredths)	2.42%	0.68%
Class 2 Units [Member]
Per unit operating performance [Abstract]
Net asset value per unit, beginning balance (in dollars per units)	$ 113.58	$ 98.41
Net income (loss): [Abstract]
Net investment loss (in dollars per unit)	$ (1.41)	$ (1.05)
Net gain (loss) on investments (in dollars per unit)	$ 8.95	$ (9.93)
Net (loss) income (in dollars per unit)	$ 7.54	$ (10.98)
Net asset value per unit, ending balance (in dollars per unit)	$ 121.12	$ 87.43
Ratios to average members' capital and total return [Abstract]
Total return before Incentive Allocation (in hundredths)	8.33%	(11.16%)
Incentive Allocation (in hundredths)	(1.69%)	0.00%
Total return after Incentive Allocation (in hundredths)	6.64%	(11.16%)
Net investment loss before Incentive Allocation (in hundredths)	(1.19%)	(1.13%)
Incentive Allocation (in hundredths)	(1.60%)	0.00%
Net investment loss after Incentive Allocation (in hundredths)	(2.79%)	(1.13%)
Total expenses before Incentive Allocation (in hundredths)	1.25%	1.18%
Incentive Allocation (in hundredths)	1.60%	0.00%
Total expenses after Incentive Allocation (in hundredths)	2.85%	1.18%