Holdings of New GM Securities (Details Textual) (USD $)	Mar. 31, 2013	Mar. 31, 2012
Holdings of Securities for Trust Beneficiaries (Textual) [Abstract]
Liquidating distributions payable	$ 16,555,000	$ 31,720,000
New GM Securities reserved and set aside for projected GUC Trust fees, costs and expenses	41,000,000	28,400,000
New GM securities set aside for potential taxes on distribution	407,300,000	108,600,000
New GM Common Stock [Member]
Distribution Made to Member or Limited Partner [Line Items]
Liquidating distributions in cash	$ 600,000
Number of warrants or shares pending distribution	288,600	622,637
Number of securities set aside from distribution	8,092,231	2,688,527
New GM Series A Warrants [Member]
Distribution Made to Member or Limited Partner [Line Items]
Number of warrants or shares pending distribution	262,306	565,896
Number of warrants set aside from distribution	7,356,545	2,444,116
New GM Series B Warrants [Member]
Distribution Made to Member or Limited Partner [Line Items]
Number of warrants or shares pending distribution	262,306	565,896
Number of warrants set aside from distribution	7,356,545	2,444,116