Short-Term Credit Arrangements and Borrowings (Tables)

12 Months Ended

Dec. 31, 2011

Short-Term Credit Arrangements and Borrowings [Abstract]

Schedule of Short-term Debt [Table Text Block]

	DTE Energy		Detroit Edison		MichCon		Total
	(In millions)
Unsecured letter of credit facility, expiring in December 2012	$	—	$	40	$	—	$	40
Unsecured letter of credit facility, expiring in May 2013	50		—		—		50
Unsecured letter of credit facility, expiring in August 2015	125		—		—		125
Unsecured revolving credit facility, expiring October 2016	1,100		300		400		1,800
Total credit facilities at December 31, 2011	$	1,275	$	340	$	400	$	2,015
Amounts outstanding at December 31, 2011:
Commercial paper issuances	234		—		185		419
Letters of credit	178		40		—		218
	412		40		185		637
Net availability at December 31, 2011	$	863	$	300	$	215	$	1,378