Financial and Other Derivative Instruments (Details 2)	Jun. 30, 2012 dte.volumes
Natural Gas [Member]
Derivative [Line Items]
Investment Contract Volume	699,643,452
Electricity [Member]
Derivative [Line Items]
Investment Contract Volume	48,635,782
Foreign currency exchange contracts [Member]
Derivative [Line Items]
Investment Contract Volume	21,635,737
FTR [Member]
Derivative [Line Items]
Investment Contract Volume	10,275,179