Holdings of New GM Securities - Additional Information (Detail) (USD $)	Dec. 31, 2013	Mar. 31, 2013
Distribution Made to Limited Partner [Line Items]
Liquidating distributions payable	$ 8,466,000	$ 16,555,000
Liquidating distributions payable in cash	13,000
New GM Securities reserved and set aside for projected GUC Trust fees, costs and expenses	64,800,000
New GM Securities set aside for potential Taxes on Distribution	$ 694,100,000
New GM Common Stock [Member]
Distribution Made to Limited Partner [Line Items]
Number of warrants or shares pending distribution	93,738
Number of securities set aside from distribution	8,413,905
New GM Series A Warrants [Member]
Distribution Made to Limited Partner [Line Items]
Number of warrants or shares pending distribution	85,178
Number of warrants set aside from distribution	7,648,979
New GM Series B Warrants [Member]
Distribution Made to Limited Partner [Line Items]
Number of warrants or shares pending distribution	85,178
Number of warrants set aside from distribution	7,648,979