Supplementary Quarterly Financial Information (Unaudited) (Details) (USD $) In Millions, except Per Share data, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Quarterly Financial Information Disclosure [Abstract]
Operating Revenues	$ 3,078	$ 2,595	$ 2,698	$ 3,930	$ 2,533	$ 2,387	$ 2,225	$ 2,516	$ 12,301	$ 9,661	$ 8,791
Operating Income	542	239	249	560	241	329	223	410	1,590	1,203	1,279
Net Income Attributable to DTE Energy Company	$ 299	$ 156	$ 124	$ 326	$ 124	$ 198	$ 105	$ 234	$ 905	$ 661	$ 610
Basic Earnings per Share (in dollars per share)	$ 1.68	$ 0.88	$ 0.70	$ 1.84	$ 0.70	$ 1.13	$ 0.60	$ 1.35	$ 5.11	$ 3.76	$ 3.56
Diluted Earnings per Share (in dollars per share)	$ 1.68	$ 0.88	$ 0.70	$ 1.84	$ 0.70	$ 1.13	$ 0.60	$ 1.34	$ 5.10	$ 3.76	$ 3.55