Financial Highlights (Details) (USD $)	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012
Class 0 Units [Member]
Per share operating performance [Abstract]
Net asset value per unit, beginning balance (in dollars per units)	$ 122.47	$ 126.14	$ 114.88	$ 123.17
Net loss: [Abstract]
Net investment loss (in dollars per unit)	$ (0.86)	$ (1.21)	$ (1.74)	$ (2.41)
Net (loss) gain on investments (in dollars per unit)	$ (0.48)	$ (6.16)	$ 7.99	$ (1.99)
Net (loss) income (in dollars per unit)	$ (1.34)	$ (7.37)	$ 6.25	$ (4.40)
Net asset value per unit, ending balance (in dollars per unit)	$ 121.13	$ 118.77	$ 121.13	$ 118.77
Ratios to average members' capital and total return [Abstract]
Total return before Incentive Allocation (in hundredths)	(1.09%)	(5.84%)	5.44%	(3.57%)
Incentive Allocation (in hundredths)	0.00%	0.00%	0.00%	0.00%
Total return after Incentive Allocation (in hundredths)	(1.09%)	(5.84%)	5.44%	(3.57%)
Net investment loss before Incentive Allocation (in hundredths)	(0.70%)	(0.96%)	(1.46%)	(1.96%)
Incentive Allocation (in hundredths)	0.00%	0.00%	0.00%	0.00%
Net investment loss after Incentive Allocation (in hundredths)	(0.70%)	(0.96%)	(1.46%)	(1.96%)
Total expenses before Incentive Allocation (in hundredths)	0.74%	1.26%	1.56%	2.54%
Incentive Allocation (in hundredths)	0.00%	0.00%	0.00%	0.00%
Total expenses after Incentive Allocation (in hundredths)	0.74%	1.26%	1.56%	2.54%
Class 2 Units [Member]
Per share operating performance [Abstract]
Net asset value per unit, beginning balance (in dollars per units)	$ 95.80	$ 100.65	$ 90.29	$ 98.77
Net loss: [Abstract]
Net investment loss (in dollars per unit)	$ (1.13)	$ (1.47)	$ (2.28)	$ (2.95)
Net (loss) gain on investments (in dollars per unit)	$ (0.39)	$ (4.88)	$ 6.27	$ (1.52)
Net (loss) income (in dollars per unit)	$ (1.52)	$ (6.35)	$ 3.99	$ (4.47)
Net asset value per unit, ending balance (in dollars per unit)	$ 94.28	$ 94.30	$ 94.28	$ 94.30
Ratios to average members' capital and total return [Abstract]
Total return before Incentive Allocation (in hundredths)	(1.59%)	(6.31%)	4.42%	(4.53%)
Incentive Allocation (in hundredths)	0.00%	0.00%	0.00%	0.00%
Total return after Incentive Allocation (in hundredths)	(1.59%)	(6.31%)	4.42%	(4.53%)
Net investment loss before Incentive Allocation (in hundredths)	(1.18%)	(1.46%)	(2.42%)	(2.99%)
Incentive Allocation (in hundredths)	0.00%	0.00%	0.00%	0.00%
Net investment loss after Incentive Allocation (in hundredths)	(1.18%)	(1.46%)	(2.42%)	(2.99%)
Total expenses before Incentive Allocation (in hundredths)	1.22%	1.78%	2.52%	3.57%
Incentive Allocation (in hundredths)	0.00%	0.00%	0.00%	0.00%
Total expenses after Incentive Allocation (in hundredths)	1.22%	1.78%	2.52%	3.57%