Fair Value (Details Textuals) (USD $)	3 Months Ended		12 Months Ended
	Mar. 31, 2013 dte_instances	Mar. 31, 2012	Dec. 31, 2012
Fair Value, Option, Quantitative Disclosures [Line Items]
Fair Value of Cash Equivalents Included in Restricted Cash	$ 51,000,000		$ 109,000,000
Fair Value of Cash Equivalents Included in Other Investments	14,000,000		14,000,000
Other investments	117,000,000		110,000,000
Maturity in Years for Cash and Cash Equivalents	3 months
Number of Certain Forward Market and Basis Prices Used	2
Average Maturity of Debt Securities	6 years		6 years
Unrealized losses recognized as regulatory assets	42,000,000		44,000,000
Fermi I Corresponding Regulatory Asset Treatment	0
Other than Temporary Impairment Losses, Investments, Portion Recognized in Earnings, Net	0	0
Other Comprehensive Income (Loss), Unrealized Holding Gain (Loss) on Securities Arising During Period, before Tax	0
Trading Securities, Change in Unrealized Holding Gain (Loss)	7,000,000	7,000,000
Other Comprehensive Income (Loss), Unrealized Holding Gain (Loss) on Securities Arising During Period, before Tax		0
Cash Equivalents [Member]
Fair Value, Option, Quantitative Disclosures [Line Items]
Available-for-sale Securities, Fair Value Disclosure	65,000,000		123,000,000
Equity [Member]
Fair Value, Option, Quantitative Disclosures [Line Items]
Available-for-sale Securities, Fair Value Disclosure	$ 6,000,000		$ 5,000,000