Holdings of New GM Securities - Additional Information (Detail) (USD $)	Mar. 31, 2014	Mar. 31, 2013
Distribution Made to Limited Partner [Line Items]
Liquidating distributions payable	$ 42,111,000	$ 16,555,000
Liquidating distributions payable in cash	200,000	600,000
New GM Securities reserved and set aside for projected GUC Trust fees, costs and expenses	51,600,000	41,000,000
Projected Dividend Taxes	3,500,000
New GM Securities set aside for potential Taxes on Distribution	$ 536,300,000	$ 407,300,000
New GM Common Stock [Member]
Distribution Made to Limited Partner [Line Items]
Number of warrants or shares pending distribution	575,278	288,600
Number of securities set aside from distribution	8,072,042	8,092,231
New GM Series A Warrants [Member]
Distribution Made to Limited Partner [Line Items]
Number of warrants or shares pending distribution	522,865	262,306
Number of warrants set aside from distribution	7,338,194	7,356,545
New GM Series B Warrants [Member]
Distribution Made to Limited Partner [Line Items]
Number of warrants or shares pending distribution	522,865	262,306
Number of warrants set aside from distribution	7,338,194	7,356,545