Liquidating Distributions - Additional Information (Detail) $ in Millions			12 Months Ended
	Dec. 02, 2013 Trust shares	Oct. 21, 2013 USD ($)	Mar. 31, 2016 USD ($) Trust	Mar. 31, 2015 USD ($) Trust shares	Mar. 31, 2014 Trust	Dec. 23, 2013 shares
Distribution Made to Limited Partner [Line Items]
Distribution of trust units | Trust			56	10,326	1,644,941
Cash distributions payable | $			$ 6.2	$ 0.2
Nova Scotia Matter [Member]
Distribution Made to Limited Partner [Line Items]
Disputed General Unsecured Claims Allowed | $		$ 1,550.0
Distribution of trust units | Trust	1,550,000				1,550,000
Nova Scotia Matter [Member] | 8.375% Guaranteed Notes Due December 7, 2015 [Member]
Distribution Made to Limited Partner [Line Items]
Nova Scotia Claims guaranteed notes interest rate		8.375%
Nova Scotia Claims guaranteed notes maturity date			Dec. 07, 2015
Nova Scotia Matter [Member] | 8.875% Guaranteed Notes Due July 10, 2023 [Member]
Distribution Made to Limited Partner [Line Items]
Nova Scotia Claims guaranteed notes interest rate		8.875%
Nova Scotia Claims guaranteed notes maturity date			Jul. 10, 2023
New GM Common Stock [Member]
Distribution Made to Limited Partner [Line Items]
Special excess distribution						6,735,070
GUC Trust distribution obligation				93,114
New GM Common Stock [Member] | Nova Scotia Matter [Member]
Distribution Made to Limited Partner [Line Items]
Settlement distribution	6,174,015
New GM Series A Warrants [Member]
Distribution Made to Limited Partner [Line Items]
Special excess distribution						6,122,789
GUC Trust distribution obligation				84,570
New GM Series A Warrants [Member] | Nova Scotia Matter [Member]
Distribution Made to Limited Partner [Line Items]
Settlement distribution	5,612,741
New GM Series B Warrants [Member]
Distribution Made to Limited Partner [Line Items]
Special excess distribution						6,122,789
GUC Trust distribution obligation				84,570
New GM Series B Warrants [Member] | Nova Scotia Matter [Member]
Distribution Made to Limited Partner [Line Items]
Settlement distribution	5,612,741