Liquidating Distributions (Details Textual) (USD $) In Millions, except Share data, unless otherwise specified	12 Months Ended
	Mar. 31, 2013 Distributions	Mar. 31, 2013 New GM Stock [Member]	Mar. 31, 2012 New GM Stock [Member]	Mar. 31, 2013 New GM Series A Warrants [Member]	Mar. 31, 2012 New GM Series A Warrants [Member]	Mar. 31, 2013 New GM Series B Warrants [Member]	Mar. 31, 2012 New GM Series B Warrants [Member]	Mar. 31, 2013 Cash Distribution [Member]
Liquidating Distributions (Textual) [Abstract]
Number of distribution in respect of outstanding GUC Trust Units	2
GUC Trust distribution obligation		288,600	622,637	262,306	565,896	262,306	565,896
Cash distributions payable in lieu of shares and warrants		$ 0.6						$ 0.6