Holdings of New GM Securities (Details Textual) (USD $)	Dec. 31, 2012	Mar. 31, 2012
Holdings of Securities for Trust Beneficiaries (Additional Textual) [Abstract]
Liquidating Distributions Payable	$ 67,704,000	$ 31,720,000
New GM Securities reserved and set aside for projected GUC Trust fees, costs and expenses	101,400,000
New Gm securities set aside for potential taxes on distribution	$ 293,900,000
New GM Common Stock [Member]
Holdings of Securities for Trust Beneficiaries (Textual) [Abstract]
Number of warrants or shares pending distribution	1,168,970
Number of securities set aside from distribution	6,826,720
New GM Series A Warrants [Member]
Holdings of Securities for Trust Beneficiaries (Textual) [Abstract]
Number of warrants or shares pending distribution	1,062,583
Number of warrants set aside from distribution	6,206,109
New GM Series B Warrants [Member]
Holdings of Securities for Trust Beneficiaries (Textual) [Abstract]
Number of warrants or shares pending distribution	1,062,583
Number of warrants set aside from distribution	6,206,109