Earnings Per Share (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
Basic Earnings per Share
Net Income Attributable to DTE Energy Company	$ 299	$ 156	$ 124	$ 326	$ 124	$ 198	$ 105	$ 234	$ 905	$ 661	$ 610
Average number of common shares outstanding (in shares)									177	175	171
Weighted average net restricted shares outstanding (in shares)									0	1	1
Dividends declared — common shares									475	453	413
Dividends declared — net restricted shares									1	1	1
Total distributed earnings									476	454	414
Net income less distributed earnings									429	207	196
Distributed (dividends per common share) (in dollars per share)									$ 2.69	$ 2.59	$ 2.42
Undistributed (in dollars per share)									$ 2.42	$ 1.17	$ 1.14
Total (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
Net Income Attributable to DTE Energy Company	299	156	124	326	124	198	105	234	905	661	610
Average number of common shares outstanding (in shares)									177	175	171
Average incremental shares from assumed exercise of options (in shares)									0	0	1
Common shares for dilutive calculation (in shares)									177	175	172
Weighted average net restricted shares outstanding (in shares)									0	1	1
Dividends declared — common shares									475	453	413
Dividends declared — net restricted shares									1	1	1
Total distributed earnings									476	454	414
Net income less distributed earnings									$ 429	$ 207	$ 196
Distributed (dividends per common share)									$ 2.69	$ 2.59	$ 2.42
Undistributed (in dollars per share)									$ 2.41	$ 1.17	$ 1.13
Total (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