Income Taxes (Reconciliation of Income Tax Expense to the Statutory Federal Income Tax Rate) (Details) - USD ($) $ in Millions	3 Months Ended	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Entity Information [Line Items]
Statutory rate		35.00%	35.00%	35.00%
Effective Income Tax Rate Reconciliation, Amount [Abstract]
Income Before Income Taxes		$ 1,287	$ 1,105	$ 950
Income tax expense at 35% statutory rate		450	387	333
Production tax credits		(189)	(145)	(122)
Investment tax credits		(4)	(5)	(7)
Depreciation		(4)	(4)	(4)
Noncontrolling interests		8	12	2
AFUDC equity		(18)	(10)	(8)
Employee Stock Ownership Plan dividends		(5)	(5)	(5)
Stock based compensation		(14)	0	0
Subsidiary stock loss		0	(10)	0
State and local income taxes, net of federal benefit		51	58	35
Enactment of the Tax Cuts and Jobs Act	$ (105)	(105)	0	0
Other, net		5	(7)	6
Income Tax Expense		$ 175	$ 271	$ 230
Effective income tax rate		13.60%	24.50%	24.20%
DTE Electric
Entity Information [Line Items]
Statutory rate		35.00%	35.00%	35.00%
Effective Income Tax Rate Reconciliation, Amount [Abstract]
Income Before Income Taxes		$ 928	$ 975	$ 836
Income tax expense at 35% statutory rate		325	341	293
Production tax credits		(36)	(30)	(31)
Investment tax credits		(4)	(4)	(5)
Depreciation		3	3	3
AFUDC equity		(5)	(6)	(7)
Employee Stock Ownership Plan dividends		(3)	(3)	(3)
State and local income taxes, net of federal benefit		48	56	43
Other, net		(1)	(4)	(1)
Income Tax Expense		$ 327	$ 353	$ 292
Effective income tax rate		35.20%	36.20%	34.90%