DTE Energy (DTE) 10-K 13 Feb 15 2014 FY Annual report Financial data

Document_and_Entity_Informatio

Document and Entity Information Document and Entity Information (USD $)	12 Months Ended
In Billions, except Share data, unless otherwise specified	Dec. 31, 2014	Jan. 30, 2015	Jun. 30, 2014
Document and Entity Information [Abstract]
Entity Registrant Name	DTE ENERGY CO
Entity Central Index Key	936340
Current Fiscal Year End Date	-19
Entity Filer Category	Large Accelerated Filer
Document Type	10-K
Document Period End Date	31-Dec-14
Document Fiscal Year Focus	2014
Document Fiscal Period Focus	FY
Amendment Flag	FALSE
Entity Common Stock, Shares Outstanding		177,229,483
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Public Float			$13.30

Consolidated_Statements_of_Ope

Consolidated Statements of Operations (USD $)	12 Months Ended
In Millions, except Per Share data, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Income Statement [Abstract]
Operating Revenues	$12,301	$9,661	$8,791
Operating Expenses
Fuel, purchased power and gas	5,879	4,055	3,296
Operation and maintenance	3,347	2,978	2,892
Depreciation, depletion and amortization	1,145	1,094	995
Taxes other than income	352	340	332
Asset (gains) losses and impairments, net	-12	-9	-3
Total operating expenses	10,711	8,458	7,512
Operating Income	1,590	1,203	1,279
Other (Income) and Deductions
Interest expense	429	436	440
Interest income	-10	-9	-10
Other income	-196	-201	-173
Other expenses	92	55	62
Total Other (Income) and Deductions	315	281	319
Income Before Income Taxes	1,275	922	960
Income Tax Expense	364	254	286
Income from Continuing Operations	911	668	674
Loss from Discontinued Operations, net of tax	0	0	-56
Net Income	911	668	618
Less: Net Income Attributable to Noncontrolling Interests	6	7	8
Net Income Attributable to DTE Energy Company	$905	$661	$610
Basic Earnings per Common Share
Income from continuing operations (in dollars per share)	$5.11	$3.76	$3.89
Loss from discontinued operations, net of tax (in dollars per share)	$0	$0	($0.33)
Total (in dollars per share)	$5.11	$3.76	$3.56
Diluted Earnings per Common Share
Income from continuing operations (in dollars per share)	$5.10	$3.76	$3.88
Loss from discontinued operations, net of tax (in dollars per share)	$0	$0	($0.33)
Total (in dollars per share)	$5.10	$3.76	$3.55
Weighted Average Common Shares Outstanding
Basic (in shares)	177	175	171
Diluted (in shares)	177	175	172
Dividends Declared per Common Share	$2.69	$2.59	$2.42

Consolidated_Statements_of_Com

Consolidated Statements of Comprehensive Income (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Statement of Comprehensive Income [Abstract]
Net Income	$911	$668	$618
Other comprehensive income (loss), net of tax:
Benefit obligations, net of taxes of $(9), $13 and $(1), respectively	-18	22	-2
Net unrealized gains on investments during the period, net of taxes of $1, $1 and $1, respectively	1	2	1
Foreign currency translation, net of taxes of $(2), $(1) and $—, respectively	-2	-2	1
Other comprehensive income	-19	22	0
Comprehensive income	892	690	618
Less comprehensive income attributable to noncontrolling interests	6	7	8
Comprehensive income attributable to DTE Energy Company	$886	$683	$610

Consolidated_Statements_of_Com1

Consolidated Statements of Comprehensive Income (Parenthetical) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Statement of Comprehensive Income [Abstract]
Tax effect on benefit obligation	($9)	$13	($1)
Tax effect on net unrealized gains (losses) on investments during the period	1	1	1
Tax effect on foreign currency translation	($2)	($1)	$0

Consolidated_Statements_of_Fin

Consolidated Statements of Financial Position (USD $)	Dec. 31, 2014	Dec. 31, 2013
In Millions, unless otherwise specified
Current Assets
Cash and cash equivalents	$48	$52
Restricted cash, principally Securitization	120	123
Accounts receivable (less allowance for doubtful accounts of $54 and $55, respectively)
Customer	1,504	1,542
Other	94	127
Inventories
Fuel and gas	512	363
Materials and supplies	292	265
Derivative assets	128	99
Regulatory assets	76	26
Other	313	209
Total Current Assets	3,087	2,806
Investments
Nuclear decommissioning trust funds	1,241	1,191
Other	628	603
Total Investments	1,869	1,794
Property
Property, plant and equipment	26,538	25,123
Less accumulated depreciation, depletion and amortization	-9,718	-9,323
Property, plant and equipment, net	16,820	15,800
Other Assets
Goodwill	2,018	2,018
Regulatory assets	3,651	2,837
Securitized regulatory assets	34	231
Intangible assets	102	122
Notes receivable	90	102
Derivative assets	44	27
Other	259	198
Total Noncurrent Assets	6,198	5,535
Total Assets	27,974	25,935
Current Liabilities
Accounts payable	973	962
Accrued interest	86	90
Dividends payable	122	116
Short-term borrowings	398	131
Current portion long-term debt, including capital leases	274	898
Derivative liabilities	77	195
Regulatory liabilities	153	302
Other	494	495
Total Current Liabilities	2,577	3,189
Long-Term Debt (net of current portion)
Mortgage bonds, notes and other	7,860	6,618
Securitization bonds	0	105
Junior subordinated debentures	480	480
Capital lease obligations	3	11
Total Long-Term Debt (net of current portion)	8,343	7,214
Other Liabilities
Deferred income taxes	3,776	3,321
Regulatory liabilities	667	862
Asset retirement obligations	1,962	1,827
Unamortized investment tax credit	41	47
Derivative liabilities	8	43
Accrued pension liability	1,280	653
Accrued postretirement liability	515	350
Nuclear decommissioning	182	178
Other	281	297
Total Noncurrent Liabilities	8,712	7,578
Commitments and Contingencies (Notes 8 and 17)
Equity
Common stock, without par value, 400,000,000 shares authorized, 176,991,231 and 177,087,230 shares issued and outstanding, respectively	3,904	3,907
Retained earnings	4,578	4,150
Accumulated other comprehensive loss	-155	-136
Total DTE Energy Company Equity	8,327	7,921
Noncontrolling interests	15	33
Total Equity	8,342	7,954
Total Liabilities and Equity	$27,974	$25,935

Consolidated_Statements_of_Fin1

Consolidated Statements of Financial Position (Parenthetical) (USD $)	Dec. 31, 2014	Dec. 31, 2013
In Millions, except Share data, unless otherwise specified
Current Assets:
Allowance for doubtful accounts	$54	$55
Stockholders' Equity:
Common stock, par value (in dollars per share)	$0	$0
Common stock, shares authorized (in shares)	400,000,000	400,000,000
Common stock, shares issued (in shares)	176,991,231	177,087,230
Common stock, shares outstanding (in shares)	176,991,231	177,087,230

Consolidated_Statements_of_Cas

Consolidated Statements of Cash Flows (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Operating Activities
Net Income	$911	$668	$618
Adjustments to reconcile net income to net cash from operating activities:
Depreciation, depletion and amortization	1,145	1,094	1,018
Nuclear fuel amortization	48	38	29
Allowance for equity funds used during construction	-21	-15	-13
Deferred income taxes	356	164	47
Loss on sale of non-utility business	0	0	83
Asset (gains) losses and impairments, net	-4	-8	1
Changes in assets and liabilities:
Accounts receivable, net	48	-154	52
Inventories	-177	123	35
Accounts payable	128	14	40
Accrued pension obligation	627	-644	280
Accrued postretirement obligation	165	-526	-323
Derivative assets and liabilities	-199	107	53
Regulatory assets and liabilities	-1,177	1,269	278
Other assets	-30	-24	55
Other liabilities	19	48	-44
Net cash from operating activities	1,839	2,154	2,209
Investing Activities
Plant and equipment expenditures b utility	-1,784	-1,534	-1,451
Plant and equipment expenditures b non-utility	-265	-342	-369
Proceeds from sale of non-utility business	0	0	255
Proceeds from sale of assets	45	36	38
Acquisition, net of cash acquired	0	0	-198
Proceeds from sale of nuclear decommissioning trust fund assets	1,146	1,118	759
Investment in nuclear decommissioning trust funds	-1,156	-1,134	-764
Other	-46	-50	-39
Net cash used for investing activities	-2,060	-1,906	-1,769
Financing Activities
Issuance of long-term debt, net of issuance costs	1,736	1,234	759
Redemption of long-term debt	-1,237	-961	-639
Short-term borrowings, net	267	-109	-179
Issuance of common stock	0	39	39
Repurchase of common stock	-52	0	0
Dividends on common stock	-470	-445	-407
Other	-27	-19	-16
Net cash from (used for) financing activities	217	-261	-443
Net Decrease in Cash and Cash Equivalents	-4	-13	-3
Cash and Cash Equivalents at Beginning of Period	52	65	68
Cash and Cash Equivalents at End of Period	48	52	65
Supplemental disclosure of cash information
Cash paid (received) for: Interest (net of interest capitalized)	415	418	438
Cash paid (received) for: Income taxes	-35	121	173
Cash Flow, Noncash Investing and Financing Activities Disclosure [Abstract]
Plant and equipment expenditures in accounts payable	$212	$329	$235

Consolidated_Statements_of_Cha

Consolidated Statements of Changes in Equity (USD $)	Total	Common Stock [Member]	Retained Earnings [Member]	Accumulated Other Comprehensive Loss [Member]	Non-Controlling Interest [Member]
In Millions, except Share data, unless otherwise specified
Beginning Balance at Dec. 31, 2011	$7,053	$3,417	$3,750	($158)	$44
Beginning Balance (in shares) at Dec. 31, 2011		169,247,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net Income	618		610		8
Dividends declared on common stock	-414		-414
Issuance of common stock (in shares)		684,000
Issuance of common stock	39	39
Contribution of common stock to pension plan (in shares)		1,335,000
Contribution of common stock to pension plan	80	80
Benefit obligations, net of tax	-2			-2
Net change in unrealized losses on investments, net of tax	1			1
Foreign currency translation, net of tax	1			1
Stock-based compensation, distributions to noncontrolling interests and other (in shares)		1,086,000
Stock-based compensation, distributions to noncontrolling interests and other	35	51	-2		-14
Ending Balance at Dec. 31, 2012	7,411	3,587	3,944	-158	38
Ending Balance (in shares) at Dec. 31, 2012		172,352,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net Income	668		661		7
Dividends declared on common stock	-454		-454
Issuance of common stock (in shares)		589,000
Issuance of common stock	39	39
Contribution of common stock to pension plan (in shares)		3,026,000
Contribution of common stock to pension plan	200	200
Benefit obligations, net of tax	22			22
Net change in unrealized losses on investments, net of tax	2			2
Foreign currency translation, net of tax	-2			-2
Stock-based compensation, distributions to noncontrolling interests and other (in shares)		1,120,000
Stock-based compensation, distributions to noncontrolling interests and other	68	81	-1		-12
Ending Balance at Dec. 31, 2013	7,954	3,907	4,150	-136	33
Ending Balance (in shares) at Dec. 31, 2013	177,087,230	177,087,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net Income	911		905		6
Dividends declared on common stock	-476		-476
Repurchase of common stock (in shares)		-713,000
Repurchase of common stock	-52	-52
Benefit obligations, net of tax	-18			-18
Net change in unrealized losses on investments, net of tax	1			1
Foreign currency translation, net of tax	-2			-2
Stock-based compensation, distributions to noncontrolling interests and other (in shares)		617,000
Stock-based compensation, distributions to noncontrolling interests and other	24	49	-1		-24
Ending Balance at Dec. 31, 2014	$8,342	$3,904	$4,578	($155)	$15
Ending Balance (in shares) at Dec. 31, 2014	176,991,231	176,991,000

Organization_and_Basis_of_Pres

Organization and Basis of Presentation (Notes)	12 Months Ended
	Dec. 31, 2014
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Organization and Basis of Presentation	ORGANIZATION AND BASIS OF PRESENTATION
	Corporate Structure
	DTE Energy owns the following businesses:
	•	DTE Electric is an electric utility engaged in the generation, purchase, distribution and sale of electricity to approximately 2.1 million customers in southeastern Michigan;
	•	DTE Gas is a natural gas utility engaged in the purchase, storage, transportation, distribution and sale of natural gas to approximately 1.2 million customers throughout Michigan and the sale of storage and transportation capacity; and
	•	Other businesses involved in 1) natural gas pipelines, gathering and storage; 2) power and industrial projects; and 3) energy marketing and trading operations.
	DTE Electric and DTE Gas are regulated by the MPSC. Certain activities of DTE Electric and DTE Gas, as well as various other aspects of businesses under DTE Energy are regulated by the FERC. In addition, the Company is regulated by other federal and state regulatory agencies including the NRC, the EPA, the MDEQ and the CFTC.
	References in this Report to “we”, “us”, “our”, “Company” or “DTE” are to DTE Energy and its subsidiaries, collectively.
	Basis of Presentation
	The accompanying Consolidated Financial Statements are prepared using accounting principles generally accepted in the United States of America. These accounting principles require management to use estimates and assumptions that impact reported amounts of assets, liabilities, revenues and expenses, and the disclosure of contingent assets and liabilities. Actual results may differ from the Company’s estimates.
	Principles of Consolidation
	The Company consolidates all majority-owned subsidiaries and investments in entities in which it has controlling influence. Non-majority owned investments are accounted for using the equity method when the Company is able to influence the operating policies of the investee. When the Company does not influence the operating policies of an investee, the cost method is used. These Consolidated Financial Statements also reflect the Company's proportionate interests in certain jointly owned utility plants. The Company eliminates all intercompany balances and transactions.
	The Company evaluates whether an entity is a VIE whenever reconsideration events occur. The Company consolidates VIEs for which it is the primary beneficiary. If the Company is not the primary beneficiary and an ownership interest is held, the VIE is accounted for under the equity method of accounting. When assessing the determination of the primary beneficiary, the Company considers all relevant facts and circumstances, including: the power, through voting or similar rights, to direct the activities of the VIE that most significantly impact the VIE's economic performance and the obligation to absorb the expected losses and/or the right to receive the expected returns of the VIE. The Company performs ongoing reassessments of all VIEs to determine if the primary beneficiary status has changed.
	Legal entities within the Company's Power and Industrial Projects segment enter into long-term contractual arrangements with customers to supply energy-related products or services. The entities are generally designed to pass-through the commodity risk associated with these contracts to the customers, with the Company retaining operational and customer default risk. These entities generally are VIEs and consolidated when the Company is the primary beneficiary. In addition, we have interests in certain VIEs through which we share control of all significant activities for those entities with our partners, and therefore are accounted for under the equity method.
	The Company has variable interests in VIEs through certain of its long-term purchase and sale contracts. As of December 31, 2014, the carrying amount of assets and liabilities in the Consolidated Statements of Financial Position that relate to its variable interests under long-term purchase and sale contracts are predominately related to working capital accounts and generally represent the amounts owed by or to the Company for the deliveries associated with the current billing cycle under the contracts. The Company has not provided any significant form of financial support associated with these long-term contracts. There is no significant potential exposure to loss as a result of its variable interests through these long-term purchase and sale contracts.
	In 2001, DTE Electric financed a regulatory asset related to Fermi 2 and certain other regulatory assets through the sale of rate reduction bonds by a wholly-owned special purpose entity, Securitization. DTE Electric performs servicing activities including billing and collecting surcharge revenue for Securitization. This entity is a VIE and is consolidated by the Company.
	The maximum risk exposure for consolidated VIEs is reflected on the Company's Consolidated Statements of Financial Position. For non-consolidated VIEs, the maximum risk exposure is generally limited to its investment and amounts which it has guaranteed.
	The following table summarizes the major balance sheet items for consolidated VIEs as of December 31, 2014 and 2013. All assets and liabilities of a consolidated VIE are presented where it has been determined that a consolidated VIE has either (1) assets that can be used only to settle obligations of the VIE or (2) liabilities for which creditors do not have recourse to the general credit of the primary beneficiary. VIEs, in which the Company holds a majority voting interest and is the primary beneficiary, that meet the definition of a business and whose assets can be used for purposes other than the settlement of the VIE's obligations have been excluded from the table below.
		December 31, 2014						December 31, 2013
		Securitization		Other		Total		Securitization		Other		Total
		(In millions)
	ASSETS
	Cash and cash equivalents	$	—	$	7	$	7	$	—	$	12	$	12
	Restricted cash	96		8		104		100		8		108
	Accounts receivable	26		15		41		34		16		50
	Inventories	—		67		67		—		118		118
	Property, plant and equipment, net	—		81		81		—		99		99
	Securitized regulatory assets	34		—		34		231		—		231
	Other current and long-term assets	1		6		7		4		9		13
		$	157	$	184	$	341	$	369	$	262	$	631
	LIABILITIES
	Accounts payable and accrued current liabilities	$	3	$	8	$	11	$	7	$	23	$	30
	Current portion long-term debt, including capital leases	105		10		115		196		9		205
	Current regulatory liabilities	32		—		32		43		—		43
	Mortgage bonds, notes and other	—		15		15		—		21		21
	Securitization bonds	—		—		—		105		—		105
	Capital lease obligations	—		3		3		—		7		7
	Other current and long-term liabilities	9		6		15		8		6		14
		$	149	$	42	$	191	$	359	$	66	$	425
	Amounts for non-consolidated VIEs as of December 31, 2014 and 2013 are as follows:
		31-Dec-14		31-Dec-13
		(In millions)
	Other investments	$	134	$	141
	Notes receivable	$	15	$	8

Significant_Accounting_Policie

Significant Accounting Policies (Notes)	12 Months Ended
	Dec. 31, 2014
Accounting Policies [Abstract]
Significant Accounting Policies	SIGNIFICANT ACCOUNTING POLICIES
	Revenues
	Revenues from the sale and delivery of electricity, and the sale, delivery and storage of natural gas are recognized as services are provided. DTE Electric and DTE Gas record revenues for electricity and gas provided but unbilled at the end of each month. Rates for DTE Electric and DTE Gas include provisions to adjust billings for fluctuations in fuel and purchased power costs, cost of natural gas and certain other costs. Revenues are adjusted for differences between actual costs subject to reconciliation and the amounts billed in current rates. Under or over recovered revenues related to these cost recovery mechanisms are recorded on the Consolidated Statements of Financial Position and are recovered or returned to customers through adjustments to the billing factors.
	For further discussion of recovery mechanisms authorized by the MPSC see Note 8 to the Consolidated Financial Statements, "Regulatory Matters".
	Non-utility businesses recognize revenues as services are provided and products are delivered. For discussion of derivative contracts see Note 12 to the Consolidated Financial Statements, "Financial and Other Derivative Instruments".
	Other Income
	Other income is recognized for non-operating income such as equity earnings, allowance for equity funds used during construction and contract services. Power & Industrial Projects also recognizes Other income in connection with the sale of membership interests in reduced emissions fuel facilities to investors. In exchange for the cash received, the investors will receive a portion of the economic attributes of the facilities, including income tax attributes. The transactions are not treated as a sale of membership interests for financial reporting purposes. Other income is considered earned when refined coal is produced and tax credits are generated. Power & Industrial Projects recognized approximately $78 million, $81 million and $63 million of Other income for the years ended December 31, 2014, 2013 and 2012, respectively.
	Accounting for ISO Transactions
	DTE Electric participates in the energy market through MISO. MISO requires that we submit hourly day-ahead, real- time and FTR bids and offers for energy at locations across the MISO region. DTE Electric accounts for MISO transactions on a net hourly basis in each of the day-ahead, real-time and FTR markets and net transactions across all MISO energy market locations. In any single hour DTE Electric records net purchases in Fuel, purchased power and gas and net sales in Operating revenues on the Consolidated Statements of Operations.
	Energy Trading participates in the energy markets through various independent system operators and regional transmission organizations (ISOs and RTOs). These markets require that Energy Trading submits hourly day-ahead, real-time bids and offers for energy at locations across each region. Energy Trading submits bids in the annual and monthly auction revenue rights and FTR auctions to the regional transmission organizations. Energy Trading accounts for these transactions on a net hourly basis for the day-ahead, real-time and FTR markets. These transactions are related to trading contracts which are presented on a net basis in Operating Revenues in the Consolidated Statements of Operations.
	DTE Electric and Energy Trading record accruals for future net purchases adjustments based on historical experience, and reconcile accruals to actual costs when invoices are received from MISO, and other ISOs and RTOs.
	Changes in Accumulated Other Comprehensive Loss
	Comprehensive income (loss) is the change in common shareholders’ equity during a period from transactions and events from non-owner sources, including net income. The amounts recorded to accumulated other comprehensive loss include unrealized gains and losses from derivatives accounted for as cash flow hedges, unrealized gains and losses on available-for-sale securities and the Company’s interest in other comprehensive income of equity investees, which comprise the net unrealized gains and losses on investments, changes in benefit obligations, consisting of deferred actuarial losses, prior service costs, and foreign currency translation adjustments.
	The following table summarizes the changes in Accumulated other comprehensive loss by component for the years ended December 31, 2014 and 2013:
		Changes in Accumulated Other Comprehensive Loss by Component (a)
		Net			Net			Benefit			Foreign			Total
		Unrealized			Unrealized			Obligations			Currency
		Gain/(Loss)			Gain/(Loss)			(b)			Translation
		on Derivatives			on Investments
		(In millions)
	Balance, January 1, 2013	$	(4	)	$	(8	)	$	(148	)	$	2		$	(158	)
	Other comprehensive income (loss) before reclassifications	—			2			13			(2		)	13
	Amounts reclassified from accumulated other comprehensive income	—			—			9			—			9
	Net current-period other comprehensive income (loss)	—			2			22			(2		)	22
	Balance, December 31, 2013	$	(4	)	$	(6	)	$	(126	)	$	—		$	(136	)
	Other comprehensive income (loss) before reclassifications	—			1			(25		)	(2		)	(26		)
	Amounts reclassified from accumulated other comprehensive income	—			—			7			—			7
	Net current-period other comprehensive income (loss)	—			1			(18		)	(2		)	(19		)
	Balance, December 31, 2014	$	(4	)	$	(5	)	$	(144	)	$	(2	)	$	(155	)
	______________________________________
	(a)All amounts are net of tax.
	(b)	The amounts reclassified from accumulated other comprehensive income (loss) are included in the computation of the net periodic pension and other postretirement benefit costs (see Note 18 to the Consolidated Financial Statements "Retirement Benefits and Trusteed Assets").
	Cash, Cash Equivalents and Restricted Cash
	Cash and cash equivalents include cash on hand, cash in banks and temporary investments purchased with remaining maturities of three months or less. Restricted cash consists of funds held to satisfy requirements of certain debt, primarily Securitization bonds, and partnership operating agreements. Restricted cash designated for interest and principal payments within one year is classified as a current asset.
	Receivables
	Accounts receivable are primarily composed of trade receivables and unbilled revenue. Our accounts receivable are stated at net realizable value.
	The allowance for doubtful accounts for DTE Electric and DTE Gas is generally calculated using the aging approach that utilizes rates developed in reserve studies. We establish an allowance for uncollectible accounts based on historical losses and management’s assessment of existing economic conditions, customer trends, and other factors. Customer accounts are generally considered delinquent if the amount billed is not received by the due date, which is typically in 21 days, however, factors such as assistance programs may delay aggressive action. We assess late payment fees on trade receivables based on past-due terms with customers. Customer accounts are written off when collection efforts have been exhausted. The time period for write-off is 150 days after service has been terminated.
	The customer allowance for doubtful accounts for our other businesses is calculated based on specific review of probable future collections based on receivable balances in excess of 30 days.
	Unbilled revenues of $773 million and $815 million are included in customer accounts receivable at December 31, 2014 and 2013, respectively.
	Notes Receivable
	Notes receivable, or financing receivables, are primarily comprised of capital lease receivables and loans and are included in Notes receivable and Other current assets on the Company’s Consolidated Statements of Financial Position.
	Notes receivable are typically considered delinquent when payment is not received for periods ranging from 60 to 120 days. The Company ceases accruing interest (nonaccrual status), considers a note receivable impaired, and establishes an allowance for credit loss when it is probable that all principal and interest amounts due will not be collected in accordance with the contractual terms of the note receivable. Cash payments received on nonaccrual status notes receivable, that do not bring the account contractually current, are first applied to contractually owed past due interest, with any remainder applied to principal. Accrual of interest is generally resumed when the note receivable becomes contractually current.
	In determining the allowance for credit losses for notes receivable, we consider the historical payment experience and other factors that are expected to have a specific impact on the counterparty’s ability to pay. In addition, the Company monitors the credit ratings of the counterparties from which we have notes receivable.
	Inventories
	The Company generally values inventory at average cost.
	Natural gas inventory of $43 million and $4 million as of December 31, 2014 and 2013, respectively, at DTE Gas is determined using the last-in, first-out (LIFO) method. At December 31, 2014, the replacement cost of gas remaining in storage exceeded the LIFO cost by $110 million. At December 31, 2013, the replacement cost of gas remaining in storage exceeded the LIFO cost by $170 million.
	Property, Retirement and Maintenance, and Depreciation, Depletion and Amortization
	Property is stated at cost and includes construction-related labor, materials, overheads and AFUDC for utility property. The cost of utility properties retired is charged to accumulated depreciation. Expenditures for maintenance and repairs are charged to expense when incurred, except for Fermi 2.
	Utility property at DTE Electric and DTE Gas is depreciated over its estimated useful life using straight-line rates approved by the MPSC.
	Non-utility property is depreciated over its estimated useful life using the straight-line and units of production methods.
	Depreciation, depletion and amortization expense also includes the amortization of certain regulatory assets.
	Approximately $16 million and $26 million of expenses related to Fermi 2 refueling outages were accrued at December 31, 2014 and 2013, respectively. Amounts are accrued on a pro-rata basis, generally over an 18-month period, that coincides with scheduled refueling outages at Fermi 2. This accrual of outage costs matches the regulatory recovery of these costs in rates set by the MPSC. See Note 8 to the Consolidated Financial Statements, "Regulatory Matters".
	The cost of nuclear fuel is capitalized. The amortization of nuclear fuel is included within Fuel, purchased power, and gas in the Consolidated Statements of Operations and is recorded using the units-of-production method.
	Long-Lived Assets
	Long-lived assets are reviewed for impairment whenever events or changes in circumstances indicate the carrying amount of an asset may not be recoverable. If the carrying amount of the asset exceeds the expected discounted future cash flows generated by the asset, an impairment loss is recognized resulting in the asset being written down to its estimated fair value. Assets to be disposed of are reported at the lower of the carrying amount or fair value, less costs to sell.
	Intangible Assets
	The Company has certain intangible assets relating to emission allowances, renewable energy credits and non-utility contracts as shown below:
		December 31, 2014			December 31, 2013
		(In millions)
	Emission allowances	$	1		$	2
	Renewable energy credits	45			51
	Contract intangible assets	122			126
		168			179
	Less accumulated amortization	57			45
Intangible assets, net	111			134
Less current intangible assets	9			12
	$	102		$	122
Emission allowances and renewable energy credits are charged to expense, using average cost, as the allowances and credits are consumed in the operation of the business. The Company amortizes contract intangible assets on a straight-line basis over the expected period of benefit, ranging from 1 to 27 years. Intangible assets amortization expense was $12 million in 2014, $14 million in 2013 and $6 million in 2012.
The following table summarizes the estimated amortization expense expected to be recognized during each year through 2019:
Estimated amortization expense	(In millions)
2015	$	12
2016	$	11
2017	$	8
2018	$	8
2019	$	6
Excise and Sales Taxes
The Company records the billing of excise and sales taxes as a receivable with an offsetting payable to the applicable taxing authority, with no net impact on the Consolidated Statements of Operations.
Deferred Debt Costs
The costs related to the issuance of long-term debt are deferred and amortized over the life of each debt issue. In accordance with MPSC regulations applicable to the Company’s electric and gas utilities, the unamortized discount, premium and expense related to utility debt redeemed with a refinancing are amortized over the life of the replacement issue. Discount, premium and expense on early redemptions of debt associated with non-utility operations are charged to earnings.
Investments in Debt and Equity Securities
The Company generally classifies investments in debt and equity securities as either trading or available-for-sale and has recorded such investments at market value with unrealized gains or losses included in earnings or in other comprehensive income or loss, respectively. Changes in the fair value of Fermi 2 nuclear decommissioning investments are recorded as adjustments to regulatory assets or liabilities, due to a recovery mechanism from customers. The Company’s equity investments are reviewed for impairment each reporting period. If the assessment indicates that the impairment is other than temporary, a loss is recognized resulting in the equity investment being written down to its estimated fair value. See Note 11 of the Consolidated Financial Statements, "Fair Value".
Government Grants
Grants are recognized when there is reasonable assurance that the grant will be received and that any conditions associated with the grant will be met. When grants are received related to Property, plant and equipment, the Company reduces the cost of the assets on the Consolidated Statements of Financial Position, resulting in lower depreciation expense over the life of the associated asset. Grants received related to expenses are reflected as a reduction of the associated expense in the period in which the expense is incurred.
DTE Energy Foundation
Charitable contributions to the DTE Energy Foundation were $25 million, $18 million and $21 million for the years ended December 31, 2014, 2013 and 2012, respectively. The DTE Energy Foundation is a non-consolidated not-for-profit private foundation, the purpose of which is to contribute to and assist charitable organizations.
Other Accounting Policies
See the following notes for other accounting policies impacting the Company’s Consolidated Financial Statements:
Note		Title
7		Asset Retirement Obligations
8		Regulatory Matters
9		Income Taxes
11		Fair Value
12		Financial and Other Derivative Instruments
19		Stock-Based Compensation

Accounting_Pronouncements_Note

Accounting Pronouncements (Notes)	12 Months Ended
	Dec. 31, 2014
New Accounting Pronouncements and Changes in Accounting Principles [Abstract]
New Accounting Pronouncements	NEW ACCOUNTING PRONOUNCEMENTS
	In May 2014, the FASB issued Accounting Standards Update (ASU) No. 2014-09, Revenue from Contracts with Customers. The objectives of this ASU are to improve upon revenue recognition requirements by providing a single comprehensive model to determine the measurement of revenue and timing of recognition. The core principle is that an entity will recognize revenue to depict the transfer of goods or services to customers at an amount that the entity expects to be entitled to in exchange for those goods or services. This ASU also requires expanded qualitative and quantitative disclosures regarding the nature, amount, timing, and uncertainty of revenues and cash flows arising from contracts with customers. The revenue standard is effective for the first interim period within annual reporting periods beginning after December 15, 2016 and is to be applied retrospectively. Early adoption is not permitted. The Company is currently assessing the impact of this ASU on its Consolidated Financial Statements.

Discontinued_Operations_Notes

Discontinued Operations (Notes)	12 Months Ended
	Dec. 31, 2014
Discontinued Operations and Disposal Groups [Abstract]
Discontinued Operations	DISCONTINUED OPERATIONS
	Sale of Unconventional Gas Production Business
	In December 2012, the Company sold its 100% equity interest in its Unconventional Gas Production business which consisted of gas and oil production assets in the western Barnett and Marble Falls shale areas of Texas. The sale resulted in gross proceeds of approximately $255 million, which resulted in a pre-tax loss of approximately $83 million ($55 million after tax). The activity of the discontinued business is shown below. The amounts exclude general corporate overhead costs, and related tax effects, and no portion of corporate interest costs were allocated to discontinued operations.
		2012
		(In millions)
	Operating Revenues	$	55
	Operation and maintenance	24
	Depreciation, depletion and amortization	23
	Taxes other than income	4
	Asset (gains) losses, net	83
		134
	Operating Loss	(79		)
	Other (Income) and Deductions	6
	Loss Before Income Taxes	(85		)
	Income Tax Benefit	(29		)
	Net Loss Attributable to DTE Energy Company	$	(56	)

Property_Plant_and_Equipment_N

Property, Plant and Equipment (Notes)	12 Months Ended
	Dec. 31, 2014
Property, Plant and Equipment [Abstract]
Property, Plant and Equipment	PROPERTY, PLANT AND EQUIPMENT
	Summary of property by classification as of December 31:
		2014				2013
		(In millions)
	Property, Plant and Equipment
	DTE Electric
	Generation	$	11,641			$	11,127
	Distribution	8,164				7,603
	Total DTE Electric	19,805				18,730
	DTE Gas
	Distribution	2,946				2,834
	Storage	448				431
	Other	863				836
	Total DTE Gas	4,257				4,101
	Non-utility and other	2,476				2,292
	Total	26,538				25,123
	Less Accumulated Depreciation, Depletion and Amortization
	DTE Electric
	Generation	(4,149		)		(4,004		)
	Distribution	(3,067		)		(2,947		)
	Total DTE Electric	(7,216		)		(6,951		)
	DTE Gas
	Distribution	(1,130		)		(1,129		)
	Storage	(142		)		(138		)
	Other	(363		)		(338		)
	Total DTE Gas	(1,635		)		(1,605		)
	Non-utility and other	(867		)		(767		)
	Total	(9,718		)		(9,323		)
	Net Property, Plant and Equipment	$	16,820			$	15,800
	AFUDC and interest capitalized was approximately $37 million and $33 million for the years ended December 31, 2014 and 2013, respectively.
	The composite depreciation rate for DTE Electric was approximately 3.4% in 2014 and 2013 and 3.3% in 2012. The composite depreciation rate for DTE Gas was 2.4% in 2014, 2013 and 2012. The average estimated useful life for each major class of utility property, plant and equipment as of December 31, 2014 follows:
			Estimated Useful Lives in Years
	Utility		Generation		Distribution		Storage
	Electric		40		41		N/A
	Gas		N/A		50		53
	The estimated useful lives for major classes of non-utility assets and facilities range from 3 to 55 years.
	Capitalized software costs are classified as Property, plant and equipment and the related amortization is included in Accumulated depreciation, depletion and amortization on the Consolidated Statements of Financial Position. The Company capitalizes the costs associated with computer software it develops or obtains for use in its business. The Company amortizes capitalized software costs on a straight-line basis over the expected period of benefit, ranging from 3 to 15 years.
	Capitalized software costs amortization expense was $77 million in 2014, $71 million in 2013 and $68 million in 2012. The gross carrying amount and accumulated amortization of capitalized software costs at December 31, 2014 were $668 million and $335 million, respectively. The gross carrying amount and accumulated amortization of capitalized software costs at December 31, 2013 were $611 million and $323 million, respectively.
	Gross property under capital leases was $35 million at December 31, 2014 and 2013. Accumulated amortization of property under capital leases was $27 million and $21 million at December 31, 2014 and 2013, respectively.

Jointly_Owned_Utility_Plant_No

Jointly Owned Utility Plant (Notes)	12 Months Ended
	Dec. 31, 2014
Jointly Owned Utility Plant, Net Ownership Amount [Abstract]
Jointly Owned Utility Plant	JOINTLY OWNED UTILITY PLANT
	DTE Electric has joint ownership interest in two power plants, Belle River and Ludington Hydroelectric Pumped Storage. DTE Electric’s share of direct expenses of the jointly owned plants are included in Fuel, purchased power and gas and Operation and maintenance expenses in the Consolidated Statements of Operations. Ownership information of the two utility plants as of December 31, 2014 was as follows:
		Belle River			Ludington
					Hydroelectric
					Pumped Storage
	In-service date	1984-1985			1973
	Total plant capacity	1,270		MW	1,872		MW
	Ownership interest	(a)			49		%
	Investment in property, plant and equipment (in millions)	$	1,742		$	412
	Accumulated depreciation (in millions)	$	993		$	175
	_______________________________________
	(a)	DTE Electric's ownership interest is 63% in Unit No. 1, 81% of the facilities applicable to Belle River used jointly by the Belle River and St. Clair Power Plants and 75% in common facilities used at Unit No. 2.
	Belle River
	The Michigan Public Power Agency (MPPA) has an ownership interest in Belle River Unit No. 1 and other related facilities. The MPPA is entitled to 19% of the total capacity and energy of the plant and is responsible for the same percentage of the plant’s operation, maintenance and capital improvement costs.
	Ludington Hydroelectric Pumped Storage
	Consumers Energy Company has an ownership interest in the Ludington Hydroelectric Pumped Storage Plant. Consumers Energy is entitled to 51% of the total capacity and energy of the plant and is responsible for the same percentage of the plant’s operation, maintenance and capital improvement costs.

Asset_Retirement_Obligations_N

Asset Retirement Obligations (Notes)	12 Months Ended
	Dec. 31, 2014
Asset Retirement Obligation Disclosure [Abstract]
Asset Retirement Obligations	ASSET RETIREMENT OBLIGATIONS
	The Company has a legal retirement obligation for the decommissioning costs for its Fermi 1 and Fermi 2 nuclear plants, dismantlement of facilities located on leased property and various other operations. The Company has conditional retirement obligations for gas pipelines, asbestos and PCB removal at certain of its power plants and various distribution equipment. The Company recognizes such obligations as liabilities at fair market value when they are incurred, which generally is at the time the associated assets are placed in service. Fair value is measured using expected future cash outflows discounted at our credit-adjusted risk-free rate. In its regulated operations, the Company recognizes regulatory assets or liabilities for timing differences in expense recognition for legal asset retirement costs that are currently recovered in rates.
	If a reasonable estimate of fair value cannot be made in the period in which the retirement obligation is incurred, such as for assets with indeterminate lives, the liability is recognized when a reasonable estimate of fair value can be made. Natural gas storage system assets, substations, manholes and certain other distribution assets have an indeterminate life. Therefore, no liability has been recorded for these assets.
	A reconciliation of the asset retirement obligations for 2014 follows:
		(In millions)
	Asset retirement obligations at December 31, 2013	$	1,827
	Accretion	112
	Liabilities incurred	11
	Liabilities settled	(12		)
	Revision in estimated cash flows	24
	Asset retirement obligations at December 31, 2014	$	1,962
	Approximately $1.7 billion of the asset retirement obligations represent nuclear decommissioning liabilities that are funded through a surcharge to electric customers over the life of the Fermi 2 nuclear plant. The NRC has jurisdiction over the decommissioning of nuclear power plants and requires minimum decommissioning funding based upon a formula. The MPSC and FERC regulate the recovery of costs of decommissioning nuclear power plants and both require the use of external trust funds to finance the decommissioning of Fermi 2. Rates approved by the MPSC provide for the recovery of decommissioning costs of Fermi 2 and the disposal of low-level radioactive waste. DTE Electric is continuing to fund FERC jurisdictional amounts for decommissioning even though explicit provisions are not included in FERC rates. The Company believes the MPSC and FERC collections will be adequate to fund the estimated cost of decommissioning. The decommissioning assets, anticipated earnings thereon and future revenues from decommissioning collections will be used to decommission Fermi 2. The Company expects the liabilities to be reduced to zero at the conclusion of the decommissioning activities. If amounts remain in the trust funds for Fermi 2 following the completion of the decommissioning activities, those amounts will be disbursed based on rulings by the MPSC and FERC.
	A portion of the funds recovered through the Fermi 2 decommissioning surcharge and deposited in external trust accounts is designated for the removal of non-radioactive assets and returning the site to greenfield. This removal and greenfielding is not considered a legal liability. Therefore, it is not included in the asset retirement obligation, but is reflected as the Nuclear decommissioning liability. The decommissioning of Fermi 1 is funded by DTE Electric. Contributions to the Fermi 1 trust are discretionary. For additional discussion of Nuclear decommissioning trust fund assets see Note 11 to the Consolidated Financial Statements, "Fair Value".

Regulatory_Matters_Notes

Regulatory Matters (Notes)	12 Months Ended
	Dec. 31, 2014
Regulatory Assets and Liabilities Disclosure [Abstract]
Regulatory Matters	REGULATORY MATTERS
	Regulation
	DTE Electric and DTE Gas are subject to the regulatory jurisdiction of the MPSC, which issues orders pertaining to rates, recovery of certain costs, including the costs of generating facilities and regulatory assets, conditions of service, accounting and operating-related matters. DTE Electric is also regulated by the FERC with respect to financing authorization and wholesale electric activities. Regulation results in differences in the application of generally accepted accounting principles between regulated and non-regulated businesses.
	The Company is unable to predict the outcome of the unresolved regulatory matters discussed herein. Resolution of these matters is dependent upon future MPSC orders and appeals, which may materially impact the financial position, results of operations and cash flows of the Company.
	Regulatory Assets and Liabilities
	DTE Electric and DTE Gas are required to record regulatory assets and liabilities for certain transactions that would have been treated as revenue or expense in non-regulated businesses. Continued applicability of regulatory accounting treatment requires that rates be designed to recover specific costs of providing regulated services and be charged to and collected from customers. Future regulatory changes or changes in the competitive environment could result in the discontinuance of this accounting treatment for regulatory assets and liabilities for some or all of our businesses and may require the write-off of the portion of any regulatory asset or liability that was no longer probable of recovery through regulated rates. Management believes that currently available facts support the continued use of regulatory assets and liabilities and that all regulatory assets and liabilities are recoverable or refundable in the current regulatory environment.
	The following are balances and a brief description of the regulatory assets and liabilities at December 31:
		2014			2013
		(In millions)
	Assets
	Recoverable pension and other postretirement costs:
	Pension	$	2,284		$	1,660
	Other postretirement costs	234			—
	Asset retirement obligation	448			394
	Recoverable Michigan income taxes	267			286
	Unamortized loss on reacquired debt	67			63
	Other recoverable income taxes	66			71
	Accrued PSCR/GCR revenue	61			—
	Deferred environmental costs	59			59
	Cost to achieve Performance Excellence Process	54			75
	Recoverable income taxes related to securitized regulatory assets	19			126
	Removal costs asset	15			—
	Transitional Reconciliation Mechanism	14			—
	Other	139			129
		3,727			2,863
	Less amount included in current assets	(76		)	(26		)
		$	3,651		$	2,837
	Securitized regulatory assets	$	34		$	231
	Liabilities
	Removal costs liability	$	308		$	351
	Renewable energy	227			277
	Over recovery of Securitization	71			72
	Refundable revenue decoupling/deferred gain	67			127
	Negative pension offset	67			84
	Refundable income taxes	33			45
	Energy optimization	24			31
	Fermi 2 refueling outage	16			26
	Refundable other postretirement costs	—			72
	Accrued PSCR/GCR refund	—			65
	Other	7			14
		$	820		$	1,164
	Less amount included current liabilities	(153		)	(302		)
		$	667		$	862
	As noted below, certain regulatory assets for which costs have been incurred have been included (or are expected to be included, for costs incurred subsequent to the most recently approved rate case) in DTE Electric's or DTE Gas’s rate base, thereby providing a return on invested costs (except as noted). Certain other regulatory assets are not included in rate base but accrue recoverable carrying charges until surcharges to collect the assets are billed. Certain regulatory assets do not result from cash expenditures and therefore do not represent investments included in rate base or have offsetting liabilities that reduce rate base.
	ASSETS
	•	Recoverable pension and other postretirement costs — Accounting rules for pension and other postretirement benefit costs require, among other things, the recognition in other comprehensive income of the actuarial gains or losses and the prior service costs that arise during the period but that are not immediately recognized as components of net periodic benefit costs. DTE Electric and DTE Gas record the impact of actuarial gains or losses and prior service costs as a regulatory asset since the traditional rate setting process allows for the recovery of pension and other postretirement costs. The asset will reverse as the deferred items are amortized and recognized as components of net periodic benefit costs. (a)
	•	Asset retirement obligation — This obligation is primarily for Fermi 2 decommissioning costs. The asset captures the timing differences between expense recognition and current recovery in rates and will reverse over the remaining life of the related plant. (a)
	•	Recoverable Michigan income taxes — In July 2007, the MBT was enacted by the State of Michigan. State deferred tax liabilities were established for the Company’s utilities, and offsetting regulatory assets were recorded as the impacts of the deferred tax liabilities will be reflected in rates as the related taxable temporary differences reverse and flow through current income tax expense. In May 2011, the MBT was repealed and the MCIT was enacted. The regulatory asset was remeasured to reflect the impact of the MCIT tax rate. (a)
	•	Unamortized loss on reacquired debt — The unamortized discount, premium and expense related to debt redeemed with a refinancing are deferred, amortized and recovered over the life of the replacement issue.
	•	Other recoverable income taxes — Income taxes receivable from DTE Electric’s customers representing the difference in property-related deferred income taxes and amounts previously reflected in DTE Electric’s rates. This asset will reverse over the remaining life of the related plant. (a)
	•	Accrued PSCR/GCR revenue — Receivable for the temporary under-recovery of and carrying costs on fuel and purchased power costs incurred by DTE Electric which are recoverable through the PSCR mechanism and temporary under-recovery of and carrying costs on gas costs incurred by DTE Gas which are recoverable through the GCR mechanism.
	•	Deferred environmental costs — The MPSC approved the deferral of investigation and remediation costs associated with DTE Gas's former MGP sites. Amortization of deferred costs is over a ten-year period beginning in the year after costs were incurred, with recovery (net of any insurance proceeds) through base rate filings. (a)
	•	Cost to achieve Performance Excellence Process (PEP) — The MPSC authorized the deferral of costs to implement the PEP. These costs consist of employee severance, project management and consultant support. These costs are amortized over a ten-year period beginning with the year subsequent to the year the costs were deferred.
	•	Recoverable income taxes related to securitized regulatory assets — Receivable for the recovery of income taxes to be paid on the non-bypassable securitization bond surcharge. A non-bypassable securitization tax surcharge, which ended in December 2014, was in place to recover the income tax over a fourteen-year period. (a)
	•	Removal costs asset — Receivable for the recovery of asset removal expenditures in excess of amounts collected from customers.
	•	Transitional Reconciliation Mechanism (TRM) — The MPSC approved the recovery of the deferred net incremental revenue requirement associated with the transition of PLD customers to DTE Electric's distribution system, effective July 1, 2014. Annual reconciliations will be filed and surcharges will be implemented to recover approved amounts. (a)
	•	Securitized regulatory assets — The net book balance of the Fermi 2 nuclear plant was written off in 1998 and an equivalent regulatory asset was established. In 2001, the Fermi 2 regulatory asset and certain other regulatory assets were securitized pursuant to PA 142 and an MPSC order. A non-bypassable securitization bond surcharge, which ended in December 2014, was in place to recover the securitized regulatory asset over a fourteen-year period.
	_________________________________
	(a)	Regulatory assets not earning a return or accruing carrying charges.
	LIABILITIES
	•	Removal costs liability — The amount collected from customers for the funding of future asset removal activities.
	•	Renewable energy — Amounts collected in rates in excess of renewable energy expenditures.
	•	Over recovery of Securitization — Over recovery of securitization bond expenses.
	•	Refundable revenue decoupling / deferred gain — Amounts were originally accrued as refundable to DTE Electric customers for the change in revenue resulting from the difference between actual average sales per customer compared to the base level of average sales per customer established by the MPSC. In 2012, the MCOA issued a decision reversing the MPSC's decision to authorize a RDM for DTE Electric. The revenue decoupling liability was reversed and, after receiving an order from the MPSC to defer the resulting gain for future amortization, DTE Electric created a regulatory liability representing its obligation to refund the gain. The deferred gain is being amortized into earnings in 2014 and 2015.
•	Negative pension offset — DTE Gas's negative pension costs are not included as a reduction to its authorized rates; therefore, the Company is accruing a regulatory liability to eliminate the impact on earnings of the negative pension expense accrued. This regulatory liability will reverse to the extent DTE Gas’s pension expense is positive in future years.
•	Refundable income taxes — Income taxes refundable to DTE Gas’s customers representing the difference in property-related deferred income taxes payable and amounts recognized pursuant to MPSC authorization.
•	Energy optimization (EO) — Amounts collected in rates in excess of energy optimization expenditures.
•	Fermi 2 refueling outage — Accrued liability for refueling outage at Fermi 2 pursuant to MPSC authorization.
•	Refundable other postretirement costs — Accounting rules for other postretirement benefit costs require, among other things, the recognition in other comprehensive income of the actuarial gains or losses and the prior service costs or credits that arise during the period but that are not immediately recognized as components of net periodic benefit costs. DTE Electric and DTE Gas record the favorable impact of actuarial gains or losses and prior service credits as a regulatory liability since the impact will reduce expense in a future rate setting process as the deferred items are recognized as a component of net periodic benefit costs.
•	Accrued PSCR/GCR refund — Liability for the temporary over-recovery of and a return on power supply costs and transmission costs incurred by DTE Electric which are recoverable through the PSCR mechanism and temporary over-recovery of and a return on gas costs incurred by DTE Gas which are recoverable through the GCR mechanism.
2014 Electric Rate Case Filing
DTE Electric filed a rate case with the MPSC on December 19, 2014 requesting an increase in base rates of $370 million based on a projected twelve-month period ending June 30, 2016. The requested increase in base rates is due primarily to an increase in net plant resulting from infrastructure investments, plant acquisitions, environmental compliance and reliability improvement projects. The rate filing also included projected changes in sales, working capital, operation and maintenance expenses, return on equity and capital structure. New rates could be self-implemented in July 2015, with a final order expected in December 2015.
2010 Electric Rate Case Filing - Court of Appeals Decision
In July 2013, the MCOA issued a decision relating to an appeal of the October 2011 MPSC order in DTE Electric's October 2010 rate case filing. The MCOA found that the record of evidence in the 2010 rate case order was insufficient to support the MPSC's authorization to recover costs for the AMI program and remanded this matter to the MPSC. The MPSC had approved an approximately $11 million rate increase related to the AMI program in the October 2011 order. DTE Electric is currently operating its AMI program pursuant to the MPSC's approval set forth in the October 2011 order. In August 2013, the MPSC reopened the 2010 electric rate case for the limited purpose of addressing the MCOA's opinion on AMI. On November 6, 2014, the MPSC issued an order affirming the recovery of costs associated with the AMI program.
Customer360 Accounting Authority
In July 2014, DTE Electric filed an application for accounting authority to defer certain costs associated with implementing Customer360, which is an integrated software application that enables improved interface among customer service, billing, meter reading, credit and collections, device management, account management, and retail access. The estimated implementation cost of Customer360 is approximately $215 million and DTE Electric proposed an amortization period of 15 years. On September 26, 2014, the MPSC approved the accounting request.
Refundable Revenue Decoupling / Deferred Gain Amortization
In September 2012, the MPSC approved DTE Electric's accounting application to defer for future amortization the gain resulting from the reversal of the Company's $127 million regulatory liability associated with the operation of the RDM. The approved application provided for the amortization of the regulatory liability to income, at a monthly rate of approximately $10.6 million, beginning January 2014. On April 1, 2014, the MPSC approved DTE Electric's accounting application to suspend the amortization of the RDM regulatory liability as of June 30, 2014 and to complete the amortization over the period January 2015 to June 2015. If DTE Electric's base rates are increased prior to July 1, 2015, the Company will cease amortization and refund to customers the remaining unamortized balance of the regulatory liability.
Transition of PLD Customers to DTE Electric's Distribution System
On July 19, 2013, DTE Electric filed its TRM application proposing a transitional tariff option for certain former PLD customers and a modified line extension provision. The application also proposed a recovery mechanism for the deferred net incremental revenue requirement associated with the transition. The net incremental revenue requirement includes costs to install meters and attach customers; system and customer facility upgrades and repairs; and the difference between DTE Electric's tariff rates and any transitional rates approved in the future. On May 13, 2014, the MPSC approved the TRM as requested and also ordered DTE Electric to include in the TRM the PLD transmission delivery service costs incurred while DTE Electric is temporarily relying upon PLD to operate and maintain PLD's system during the system conversion period. The meter installation phase of the transition was completed in June 2014. On July 1, 2014, former PLD customers became customers of DTE Electric.
PSCR Proceedings
The PSCR process is designed to allow DTE Electric to recover all of its power supply costs if incurred under reasonable and prudent policies and practices. DTE Electric's power supply costs include fuel and related transportation costs, purchased and net interchange power costs, nitrogen oxide and sulfur dioxide emission allowances costs, urea costs, transmission costs and MISO costs. The MPSC reviews these costs, policies and practices for prudence in annual plan and reconciliation filings.
2012 PSCR Year — In March 2013, DTE Electric filed the 2012 PSCR reconciliation calculating a net under-recovery of approximately $87 million that includes an under-recovery of approximately $148 million for the 2011 PSCR year. The reconciliation includes purchased power costs related to the manual shutdown of our Fermi 2 nuclear power plant in June 2012 caused by the failure of one of the plant's two non-safety related feed-water pumps. The plant was restarted on July 30, 2012, which restored production to approximately 68% of full capacity. In September 2013, the repair to the plant was completed and production was returned to full capacity. DTE Electric was able to purchase sufficient power from MISO to continue to provide uninterrupted service to our customers. Certain intervenors in the reconciliation case have challenged the recovery of up to $32 million of the Fermi 2 related purchased power costs. Resolution of this matter is expected in 2015.
DTE Gas Infrastructure Recovery Mechanism (IRM)
In November 2014, DTE Gas filed an application with the MPSC for approval of an increased IRM surcharge to recover an additional $47 million of annual capital expenditures in 2016 and 2017 for its gas main renewal program. Resolution of this matter is anticipated in 2015.

Income_Taxes_Notes

Income Taxes (Notes)	12 Months Ended
	Dec. 31, 2014
Income Tax Disclosure [Abstract]
Income Taxes	INCOME TAXES
	Income Tax Summary
	The Company files a consolidated federal income tax return. Total income tax expense varied from the statutory federal income tax rate for the following reasons:
		2014			2013			2012
		(In millions)
	Income before income taxes	$	1,275		$	922		$	960
	Income tax expense at 35% statutory rate	$	446		$	323		$	336
	Production tax credits	(119		)	(68		)	(49		)
	Investment tax credits	(6		)	(6		)	(6		)
	Depreciation	(4		)	(4		)	(4		)
	AFUDC - Equity	(7		)	(5		)	(4		)
	Employee Stock Ownership Plan dividends	(4		)	(4		)	(4		)
	Domestic production activities deduction	—			(14		)	(14		)
	State and local income taxes, net of federal benefit	51			37			37
	Enactment of New York Corporate Income Tax Legislation, net of federal benefit	8			—			—
	Other, net	(1		)	(5		)	(6		)
	Income tax expense	$	364		$	254		$	286
	Effective income tax rate	28.5		%	27.5		%	29.8		%
	Components of income tax expense were as follows:
		2014			2013			2012
		(In millions)
	Current income tax expense (benefit)
	Federal	$	(16	)	$	74		$	190
	State and other income tax	24			16			49
	Total current income taxes	8			90			239
	Deferred income tax expense
	Federal	289			122			39
	State and other income tax	67			42			8
	Total deferred income taxes	356			164			47
	Total income taxes from continuing operations	364			254			286
	Discontinued operations	—			—			(29		)
	Total	$	364		$	254		$	257
	Deferred tax assets and liabilities are recognized for the estimated future tax effect of temporary differences between the tax basis of assets or liabilities and the reported amounts in the financial statements. Deferred tax assets and liabilities are classified as current or noncurrent according to the classification of the related assets or liabilities. Deferred tax assets and liabilities not related to assets or liabilities are classified according to the expected reversal date of the temporary differences. Consistent with rate making treatment, deferred taxes are offset in the table below for temporary differences which have related regulatory assets and liabilities.
	Deferred tax assets (liabilities) were comprised of the following at December 31:
		2014			2013
		(In millions)
	Property, plant and equipment	$	(3,832	)	$	(3,372	)
	Securitized regulatory assets	(2		)	(127		)
	Tax credit carry-forwards	296			266
	Pension and benefits	(152		)	(30		)
	State net operating loss and credit carry-forwards	39			43
	Other	(19		)	(92		)
		(3,670		)	(3,312		)
	Less valuation allowance	(31		)	(37		)
		$	(3,701	)	$	(3,349	)
	Current deferred income tax assets (liabilities)	$	75		$	(28	)
	Long-term deferred income tax liabilities	(3,776		)	(3,321		)
		$	(3,701	)	$	(3,349	)
	Deferred income tax assets	$	861		$	934
	Deferred income tax liabilities	(4,562		)	(4,283		)
		$	(3,701	)	$	(3,349	)
	Tax credit carry forwards include $29 million of general business credits that expire through 2034 and $267 million of alternative minimum tax credits that may be carried forward indefinitely. The alternative minimum tax credits are production tax credits earned prior to 2006 but not utilized. The majority of these alternative minimum tax credits were generated from projects that had received a private letter ruling (PLR) from the IRS. These PLRs provide assurance as to the appropriateness of using these credits to offset taxable income, however, these tax credits are subject to IRS audit and adjustment.
	The above table excludes unamortized investment tax credits that are shown separately on the Consolidated Statements of Financial Position. Investment tax credits are deferred and amortized to income over the average life of the related property.
	The Company has state deferred tax assets related to net operating loss and credit carry-forwards of $39 million and $43 million at December 31, 2014 and 2013, respectively. The state net operating loss and credit carry-forwards expire from 2015 through 2034. The Company has recorded valuation allowances at December 31, 2014 and 2013 of approximately $31 million and $37 million, respectively, with respect to these deferred tax assets. In assessing the realizability of deferred tax assets, the Company considers whether it is more likely than not that some portion or all of the deferred tax assets will not be realized. The ultimate realization of deferred tax assets is dependent upon the generation of future taxable income during the periods in which those temporary differences become deductible.
	Uncertain Tax Positions
	A reconciliation of the beginning and ending amount of unrecognized tax benefits is as follows:
		2014			2013			2012
		(In millions)
	Balance at January 1	$	10		$	11		$	48
	Reductions for tax positions of prior years	—			—			(2		)
	Additions for tax positions of current year	—			—			1
	Settlements	—			—			(30		)
	Lapse of statute of limitations	(1		)	(1		)	(6		)
	Balance at December 31	$	9		$	10		$	11
The Company had $2 million of unrecognized tax benefits at December 31, 2014 and 2013, that, if recognized, would favorably impact its effective tax rate. During the next twelve months, it is reasonably possible that the statute of limitation will expire on various state tax returns. As a result, the Company believes that it is possible that there will be a decrease in unrecognized tax benefits of up to $6 million within the next twelve months.
The Company recognizes interest and penalties pertaining to income taxes in Interest expense and Other expenses, respectively, on its Consolidated Statements of Operations. Accrued interest pertaining to income taxes totaled $1 million at December 31, 2014 and 2013. The Company had no accrued penalties pertaining to income taxes. The Company recognized interest expense (income) related to income taxes of a nominal amount in 2014 and 2013 and $(1) million in 2012.
In 2014, the Company settled a federal tax audit for the 2012 tax year. The Company's federal income tax returns for 2013 and subsequent years remain subject to examination by the IRS. The Company's MBT and MCIT returns for the year 2008 and subsequent years remain subject to examination by the State of Michigan. The Company also files tax returns in numerous state and local jurisdictions with varying statutes of limitation.

Earnings_Per_Share_Notes

Earnings Per Share (Notes)	12 Months Ended
	Dec. 31, 2014
Earnings Per Share [Abstract]
Earnings Per Share	EARNINGS PER SHARE
	The Company reports both basic and diluted earnings per share. The calculation of diluted earnings per share assumes the issuance of potentially dilutive common shares outstanding during the period from the exercise of stock options. A reconciliation of both calculations is presented in the following table as of December 31:
		2014		2013		2012
		(In millions, expect per share amounts)
	Basic Earnings per Share
	Net income attributable to DTE Energy Company	$	905	$	661	$	610
	Average number of common shares outstanding	177		175		171
	Weighted average net restricted shares outstanding	—		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	2.42		1.17		1.14
	Total Basic Earnings per Common Share	$	5.11	$	3.76	$	3.56
	Diluted Earnings per Share
	Net income attributable to DTE Energy Company	$	905	$	661	$	610
	Average number of common shares outstanding	177		175		171
	Average incremental shares from assumed exercise of options	—		—		1
	Common shares for dilutive calculation	177		175		172
	Weighted average net restricted shares outstanding	—		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	2.41		1.17		1.13
	Total Diluted Earnings per Common Share	$	5.1	$	3.76	$	3.55

Fair_Value_Notes

Fair Value (Notes)	12 Months Ended
	Dec. 31, 2014
Fair Value Disclosures [Abstract]
Fair Value	FAIR VALUE
	Fair value is defined as the price that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date in a principal or most advantageous market. Fair value is a market-based measurement that is determined based on inputs, which refer broadly to assumptions that market participants use in pricing assets or liabilities. These inputs can be readily observable, market corroborated or generally unobservable inputs. The Company makes certain assumptions it believes that market participants would use in pricing assets or liabilities, including assumptions about risk, and the risks inherent in the inputs to valuation techniques. Credit risk of the Company and its counterparties is incorporated in the valuation of assets and liabilities through the use of credit reserves, the impact of which was immaterial at December 31, 2014 and 2013. The Company believes it uses valuation techniques that maximize the use of observable market-based inputs and minimize the use of unobservable inputs.
	A fair value hierarchy has been established that prioritizes the inputs to valuation techniques used to measure fair value in three broad levels. The fair value hierarchy gives the highest priority to quoted prices (unadjusted) in active markets for identical assets or liabilities (Level 1) and the lowest priority to unobservable inputs (Level 3). In some cases, the inputs used to measure fair value might fall in different levels of the fair value hierarchy. All assets and liabilities are required to be classified in their entirety based on the lowest level of input that is significant to the fair value measurement in its entirety. Assessing the significance of a particular input may require judgment considering factors specific to the asset or liability, and may affect the valuation of the asset or liability and its placement within the fair value hierarchy. The Company classifies fair value balances based on the fair value hierarchy defined as follows:
	•	Level 1 — Consists of unadjusted quoted prices in active markets for identical assets or liabilities that the Company has the ability to access as of the reporting date.
	•	Level 2 — Consists of inputs other than quoted prices included within Level 1 that are directly observable for the asset or liability or indirectly observable through corroboration with observable market data.
	•	Level 3 — Consists of unobservable inputs for assets or liabilities whose fair value is estimated based on internally developed models or methodologies using inputs that are generally less readily observable and supported by little, if any, market activity at the measurement date. Unobservable inputs are developed based on the best available information and subject to cost-benefit constraints.
	The following table presents assets and liabilities measured and recorded at fair value on a recurring basis as of December 31, 2014 and 2013:
		31-Dec-14																			31-Dec-13
		Level 1			Level 2				Level 3				Netting (a)				Net Balance				Level 1				Level 2			Level 3			Netting (a)			Net Balance
		(In millions)
	Assets:
	Cash equivalents (b)	$	13		$	99			$	—			$	—			$	112			$	10			$	115		$	—		$	—		$	125
	Nuclear decommissioning trusts	792			449				—				—				1,241				779				412			—			—			1,191
	Other investments (c) (d)	100			50				—				—				150				92				44			—			—			136
	Derivative assets:
	Commodity Contracts:
	Natural Gas	555			140				92				(681		)		106				273				89			34			(382		)	14
	Electricity	—			295				47				(280		)		62				—				261			139			(291		)	109
	Other	42			—				3				(42		)		3				33				1			3			(34		)	3
	Other derivative contracts (e)	—			4				—				(3		)		1				—				—			—			—			—
	Total derivative assets	597			439				142				(1,006		)		172				306				351			176			(707		)	126
	Total	$	1,502		$	1,037			$	142			$	(1,006	)		$	1,675			$	1,187			$	922		$	176		$	(707	)	$	1,578
	Liabilities:
	Derivative liabilities:
	Commodity Contracts:
	Natural Gas	$	(578	)	$	(78	)		$	(62	)		$	679			$	(39	)		$	(277	)		$	(140	)	$	(86	)	$	395		$	(108	)
	Electricity	—			(290		)		(52		)		298				(44		)		—				(272		)	(126		)	269			(129		)
	Other	(32		)	(9		)		(4		)		45				—				(32		)		(2		)	—			34			—
	Other derivative contracts (e)	—			(5		)		—				3				(2		)		—				(1		)	—			—			(1		)
	Total derivative liabilities	(610		)	(382		)		(118		)		1,025				(85		)		(309		)		(415		)	(212		)	698			(238		)
	Total	$	(610	)	$	(382	)		$	(118	)		$	1,025			$	(85	)		$	(309	)		$	(415	)	$	(212	)	$	698		$	(238	)
	Net Assets (Liabilities) at the end of the period	$	892		$	655			$	24			$	19			$	1,590			$	878			$	507		$	(36	)	$	(9	)	$	1,340
	Assets:
	Current	$	582		$	504			$	109			$	(955	)		$	240			$	277			$	400		$	139		$	(592	)	$	224
	Noncurrent (f)	920			533				33				(51		)		1,435				910				522			37			(115		)	1,354
	Total Assets	$	1,502		$	1,037			$	142			$	(1,006	)		$	1,675			$	1,187			$	922		$	176		$	(707	)	$	1,578
	Liabilities:
	Current	$	(572	)	$	(357	)		$	(112	)		$	964			$	(77	)		$	(268	)		$	(328	)	$	(177	)	$	578		$	(195	)
	Noncurrent	(38		)	(25		)		(6		)		61				(8		)		(41		)		(87		)	(35		)	120			(43		)
	Total Liabilities	$	(610	)	$	(382	)		$	(118	)		$	1,025			$	(85	)		$	(309	)		$	(415	)	$	(212	)	$	698		$	(238	)
	Net Assets (Liabilities) at the end of the period	$	892		$	655			$	24			$	19			$	1,590			$	878			$	507		$	(36	)	$	(9	)	$	1,340
	_______________________________________
	(a)	Amounts represent the impact of master netting agreements that allow the Company to net gain and loss positions and cash collateral held or placed with the same counterparties.
	(b)	At December 31, 2014, available-for-sale securities of $112 million included $105 million and $7 million of cash equivalents included in Restricted cash and Other investments on the Consolidated Statements of Financial Position, respectively. At December 31, 2013, available-for-sale securities of $125 million, included $109 million and $16 million of cash equivalents included in Restricted cash and Other investments on the Consolidated Statements of Financial Position, respectively.
	(c)	Excludes cash surrender value of life insurance investments.
	(d)	Available-for-sale equity securities of $8 million at December 31, 2014 and $7 million at December 31, 2013 are included in Other investments on the Consolidated Statements of Financial Position.
	(e)	Primarily includes Foreign currency exchange contracts.
	(f)	Includes $150 million and $136 million of Other investments that are included in the Consolidated Statements of Financial Position in Other investments at December 31, 2014 and 2013, respectively.
	Cash Equivalents
	Cash equivalents include investments with maturities of three months or less when purchased. The cash equivalents shown in the fair value table are comprised of short-term investments and money market funds.
	Nuclear Decommissioning Trusts and Other Investments
	The nuclear decommissioning trusts and other investments hold debt and equity securities directly and indirectly through institutional mutual funds. Exchange-traded debt and equity securities held directly are valued using quoted market prices in actively traded markets. The institutional mutual funds hold exchange-traded equity or debt securities and are valued based on stated NAVs. Non-exchange-traded fixed income securities are valued based upon quotations available from brokers or pricing services. A primary price source is identified by asset type, class or issue for each security. The trustee monitors prices supplied by pricing services and may use a supplemental price source or change the primary price source of a given security if the trustee determines that another price source is considered to be preferable. DTE Energy has obtained an understanding of how these prices are derived, including the nature and observability of the inputs used in deriving such prices. Additionally, DTE Energy selectively corroborates the fair value of securities by comparison of market-based price sources. Investment policies and procedures are determined by the Company's Trust Investments Department which reports to the Company's Vice President and Treasurer.
	Derivative Assets and Liabilities
	Derivative assets and liabilities are comprised of physical and financial derivative contracts, including futures, forwards, options and swaps that are both exchange-traded and over-the-counter traded contracts. Various inputs are used to value derivatives depending on the type of contract and availability of market data. Exchange-traded derivative contracts are valued using quoted prices in active markets. DTE Energy considers the following criteria in determining whether a market is considered active: frequency in which pricing information is updated, variability in pricing between sources or over time and the availability of public information. Other derivative contracts are valued based upon a variety of inputs including commodity market prices, broker quotes, interest rates, credit ratings, default rates, market-based seasonality and basis differential factors. DTE Energy monitors the prices that are supplied by brokers and pricing services and may use a supplemental price source or change the primary price source of an index if prices become unavailable or another price source is determined to be more representative of fair value. DTE Energy has obtained an understanding of how these prices are derived. Additionally, DTE Energy selectively corroborates the fair value of its transactions by comparison of market-based price sources. Mathematical valuation models are used for derivatives for which external market data is not readily observable, such as contracts which extend beyond the actively traded reporting period. The Company has established a Risk Management Committee whose responsibilities include directly or indirectly ensuring all valuation methods are applied in accordance with predefined policies. The development and maintenance of our forward price curves has been assigned to our Risk Management Department, which is separate and distinct from the trading functions within the Company.
	The following table presents the fair value reconciliation of Level 3 assets and liabilities measured at fair value on a recurring basis for the years ended December 31, 2014 and 2013:
		Year Ended December 31, 2014															Year Ended December 31, 2013
		Natural Gas			Electricity				Other				Total				Natural Gas				Electricity				Other			Total
		(In millions)
	Net Assets (Liabilities) as of December 31	$	(52	)	$	13			$	3			$	(36	)		$	(38	)		$	23			$	2		$	(13	)
	Transfers into Level 3 from Level 2	—			—				—				—				1				—				—			1
	Transfers from Level 3 into Level 2	(2		)	—				—				(2		)		—				—				—			—
	Total gains (losses):
	Included in earnings	(40		)	25				(5		)		(20		)		(32		)		75				—			43
	Recorded in regulatory assets/liabilities	—			—				8				8				—				—				5			5
Purchases, issuances and settlements:
Purchases	—			1				—				1				(8		)		1				—			(7		)
Issuances	—			(3		)		—				(3		)		—				(1		)		—			(1		)
Settlements	124			(41		)		(7		)		76				25				(85		)		(4		)	(64		)
Net Assets (Liabilities) as of December 31	$	30		$	(5	)		$	(1	)		$	24			$	(52	)		$	13			$	3		$	(36	)
The amount of total gains (losses) included in net income attributed to the change in unrealized gains (losses) related to assets and liabilities held at December 31, 2014 and 2013 and reflected in Operating revenues and Fuel, purchased power and gas in the Consolidated Statements of Operations	$	35		$	9			$	(4	)		$	40			$	(49	)		$	48			$	—		$	(1	)
Derivatives are transferred between levels primarily due to changes in the source data used to construct price curves as a result of changes in market liquidity. Transfers in and transfers out are reflected as if they had occurred at the beginning of the period. There were no transfers between levels 1 and 2 during the years ended December 31, 2014 and 2013.
The following tables present the unobservable inputs related to Level 3 assets and liabilities as of December 31, 2014 and 2013:
		December 31, 2014
Commodity Contracts		Derivative Assets			Derivative Liabilities				Valuation Techniques		Unobservable Input		Range								Weighted Average
		(In millions)
Natural Gas		$	92		$	(62	)		Discounted Cash Flow		Forward basis price (per MMBtu)		$	(2.28	) —		$	7.83	/MMBtu		$	(0.22	)/MMBtu
Electricity		$	47		$	(52	)		Discounted Cash Flow		Forward basis price (per MWh)		$	(14	) —		$	15	/MWh		$	4	/MWh
		December 31, 2013
Commodity Contracts		Derivative Assets			Derivative Liabilities				Valuation Techniques		Unobservable Input		Range								Weighted Average
		(In millions)
Natural Gas		$	34		$	(86	)		Discounted Cash Flow		Forward basis price (per MMBtu)		$	(0.88	) —		$	5.07	/MMBtu		$	(0.16	)/MMBtu
Electricity		$	139		$	(126	)		Discounted Cash Flow		Forward basis price (per MWh)		$	(7	) —		$	15	/MWh		$	3	/MWh
The unobservable inputs used in the fair value measurement of the electricity and natural gas commodity types consist of inputs that are less observable due in part to lack of available broker quotes, supported by little, if any, market activity at the measurement date or are based on internally developed models. Certain basis prices (i.e., the difference in pricing between two locations) included in the valuation of natural gas and electricity contracts were deemed unobservable.
The inputs listed above would have a direct impact on the fair values of the above security types if they were adjusted. A significant increase (decrease) in the basis price would result in a higher (lower) fair value for long positions, with offsetting impacts to short positions.
Fair Value of Financial Instruments
The fair value of financial instruments included in the table below is determined by using quoted market prices when available. When quoted prices are not available, pricing services may be used to determine the fair value with reference to observable interest rate indexes. DTE Energy has obtained an understanding of how the fair values are derived. DTE Energy also selectively corroborates the fair value of its transactions by comparison of market-based price sources. Discounted cash flow analyses based upon estimated current borrowing rates are also used to determine fair value when quoted market prices are not available. The fair values of notes receivable, excluding capital leases, are estimated using discounted cash flow techniques that incorporate market interest rates as well as assumptions about the remaining life of the loans and credit risk. Depending on the information available, other valuation techniques may be used that rely on internal assumptions and models. Valuation policies and procedures are determined by DTE Energy's Treasury Department which reports to the Company's Vice President and Treasurer.
The following table presents the carrying amount and fair value of financial instruments as of December 31, 2014 and 2013:
	December 31, 2014															December 31, 2013
	Carrying			Fair Value												Carrying				Fair Value
	Amount			Level 1				Level 2				Level 3				Amount				Level 1				Level 2			Level 3
	(In millions)
Notes receivable, excluding capital leases	$	41		$	—			$	—			$	41			$	41			$	—			$	—		$	41
Dividends payable	$	122		$	122			$	—			$	—			$	116			$	116			$	—		$	—
Short-term borrowings	$	398		$	—			$	398			$	—			$	131			$	—			$	131		$	—
Long-term debt, excluding capital leases	$	8,606		$	489			$	8,308			$	706			$	8,094			$	425			$	7,551		$	499
For further fair value information on financial and derivative instruments see Note 12 to the Consolidated Financial Statements, "Financial and Other Derivative Instruments".
Nuclear Decommissioning Trust Funds
DTE Electric has a legal obligation to decommission its nuclear power plants following the expiration of their operating licenses. This obligation is reflected as an asset retirement obligation on the Consolidated Statements of Financial Position. Rates approved by the MPSC provide for the recovery of decommissioning costs of Fermi 2 and the disposal of low-level radioactive waste. DTE Electric is continuing to fund FERC jurisdictional amounts for decommissioning even though explicit provisions are not included in FERC rates. See Note 7 to the Consolidated Financial Statements, "Asset Retirement Obligations".
The following table summarizes the fair value of the nuclear decommissioning trust fund assets:
	31-Dec-14			31-Dec-13
	(In millions)
Fermi 2	$	1,221		$	1,172
Fermi 1	3			3
Low level radioactive waste	17			16
Total	$	1,241		$	1,191
The costs of securities sold are determined on the basis of specific identification. The following table sets forth the gains and losses and proceeds from the sale of securities by the nuclear decommissioning trust funds:
	Year Ended December 31
	2014			2013				2012
	(In millions)
Realized gains	$	54		$	83			$	37
Realized losses	$	(33	)	$	(41	)		$	(31	)
Proceeds from sales of securities	$	1,146		$	1,118			$	759
Realized gains and losses from the sale of securities for the Fermi 2 and the low level radioactive waste funds are recorded to the Regulatory asset and Nuclear decommissioning liability. The following table sets forth the fair value and unrealized gains for the nuclear decommissioning trust funds:
	31-Dec-14											31-Dec-13
	Fair			Unrealized				Unrealized Losses				Fair				Unrealized				Unrealized Losses
	Value			Gains								Value				Gains
	(In millions)
Equity securities	$	756		$	204			$	(39	)		$	730			$	201			$	(25	)
Debt securities	474			21				(2		)		442				12				(6		)
Cash and cash equivalents	11			—				—				19				—				—
	$	1,241		$	225			$	(41	)		$	1,191			$	213			$	(31	)
At December 31, 2014, investments in the nuclear decommissioning trust funds consisted of approximately 61% in publicly traded equity securities, 38% in fixed debt instruments and 1% in cash equivalents. At December 31, 2013, investments in the nuclear decommissioning trust funds consisted of approximately 61% in publicly traded equity securities, 37% in fixed debt instruments and 2% in cash equivalents.
The debt securities at December 31, 2014 and 2013 had an average maturity of approximately 7 years. Securities held in the nuclear decommissioning trust funds are classified as available-for-sale. As DTE Electric does not have the ability to hold impaired investments for a period of time sufficient to allow for the anticipated recovery of market value, all unrealized losses are considered to be other-than-temporary impairments.
Unrealized losses incurred by the Fermi 2 trust are recognized as a Regulatory asset.
Other Securities
At December 31, 2014 and 2013, these securities are comprised primarily of money-market and equity securities. During the years ended December 31, 2014 and 2013, no amounts of unrealized losses on available-for-sale securities were reclassified out of other comprehensive income and realized into net income for the periods. Gains related to trading securities held at December 31, 2014, 2013 and 2012 were $14 million, $22 million and $11 million, respectively.

Financial_and_Other_Derivative

Financial and Other Derivative Instruments (Notes)	12 Months Ended
	Dec. 31, 2014
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Financial and Other Derivative Instruments	FINANCIAL AND OTHER DERIVATIVE INSTRUMENTS
	The Company recognizes all derivatives at their fair value as Derivative assets or liabilities on the Consolidated Statements of Financial Position unless they qualify for certain scope exceptions, including the normal purchases and normal sales exception. Further, derivatives that qualify and are designated for hedge accounting are classified as either hedges of a forecasted transaction or the variability of cash flows to be received or paid related to a recognized asset or liability (cash flow hedge), or as hedges of the fair value of a recognized asset or liability or of an unrecognized firm commitment (fair value hedge). For cash flow hedges, the portion of the derivative gain or loss that is effective in offsetting the change in the value of the underlying exposure is deferred in Accumulated other comprehensive income and later reclassified into earnings when the underlying transaction occurs. Gains or losses from the ineffective portion of cash flow hedges are recognized in earnings immediately. For fair value hedges, changes in fair values for the derivative and hedged item are recognized in earnings each period. For derivatives that do not qualify or are not designated for hedge accounting, changes in the fair value are recognized in earnings each period.
	The Company’s primary market risk exposure is associated with commodity prices, credit and interest rates. The Company has risk management policies to monitor and manage market risks. The Company uses derivative instruments to manage some of the exposure. The Company uses derivative instruments for trading purposes in its Energy Trading segment. Contracts classified as derivative instruments include electricity, natural gas, oil and certain coal forwards, futures, options and swaps, and foreign currency exchange contracts. Items not classified as derivatives include natural gas inventory, pipeline transportation contracts, renewable energy credits and natural gas storage assets.
	DTE Electric — DTE Electric generates, purchases, distributes and sells electricity. DTE Electric uses forward energy contracts to manage changes in the price of electricity and fuel. Substantially all of these contracts meet the normal purchases and sales exemption and are therefore accounted for under the accrual method. Other derivative contracts are MTM and recoverable through the PSCR mechanism when settled. This results in the deferral of unrealized gains and losses as Regulatory assets or liabilities until realized.
	DTE Gas — DTE Gas purchases, stores, transports, distributes and sells natural gas and sells storage and transportation capacity. DTE Gas has fixed-priced contracts for portions of its expected natural gas supply requirements through March 2017. Substantially all of these contracts meet the normal purchases and sales exemption and are therefore accounted for under the accrual method. DTE Gas may also sell forward transportation and storage capacity contracts. Forward transportation and storage contracts are generally not derivatives and are therefore accounted for under the accrual method.
	Gas Storage and Pipelines — This segment is primarily engaged in services related to the transportation and storage of natural gas. Primarily fixed-priced contracts are used in the marketing and management of transportation and storage services. Generally these contracts are not derivatives and are therefore accounted for under the accrual method.
	Power and Industrial Projects — This segment manages and operates energy and pulverized coal projects, coke batteries, reduced emissions fuel projects, landfill gas recovery and power generation assets. Primarily fixed-price contracts are used in the marketing and management of the segment assets. These contracts are generally not derivatives and are therefore accounted for under the accrual method.
	Energy Trading — Commodity Price Risk — Energy Trading markets and trades electricity, natural gas physical products and energy financial instruments, and provides energy and asset management services utilizing energy commodity derivative instruments. Forwards, futures, options and swap agreements are used to manage exposure to the risk of market price and volume fluctuations in its operations. These derivatives are accounted for by recording changes in fair value to earnings unless hedge accounting criteria are met.
	Energy Trading — Foreign Currency Exchange Risk — Energy Trading has foreign currency exchange forward contracts to economically hedge fixed Canadian dollar commitments existing under natural gas and power purchase and sale contracts and natural gas transportation contracts. The Company enters into these contracts to mitigate price volatility with respect to fluctuations of the Canadian dollar relative to the U.S. dollar. These derivatives are accounted for by recording changes in fair value to earnings unless hedge accounting criteria are met.
	Corporate and Other — Interest Rate Risk — The Company uses interest rate swaps, treasury locks and other derivatives to hedge the risk associated with interest rate market volatility.
	Credit Risk — The utility and non-utility businesses are exposed to credit risk if customers or counterparties do not comply with their contractual obligations. The Company maintains credit policies that significantly minimize overall credit risk. These policies include an evaluation of potential customers’ and counterparties’ financial condition, credit rating, collateral requirements or other credit enhancements such as letters of credit or guarantees. The Company generally uses standardized agreements that allow the netting of positive and negative transactions associated with a single counterparty. The Company maintains a provision for credit losses based on factors surrounding the credit risk of its customers, historical trends, and other information. Based on the Company’s credit policies and its December 31, 2014 and 2013 provision for credit losses, the Company’s exposure to counterparty nonperformance is not expected to have a material adverse effect on the Company’s financial statements.
	Derivative Activities
	The Company manages its MTM risk on a portfolio basis based upon the delivery period of its contracts and the individual components of the risks within each contract. Accordingly, it records and manages the energy purchase and sale obligations under its contracts in separate components based on the commodity (e.g. electricity or natural gas), the product (e.g. electricity for delivery during peak or off-peak hours), the delivery location (e.g. by region), the risk profile (e.g. forward or option), and the delivery period (e.g. by month and year). The following describes the categories of activities represented by their operating characteristics and key risks:
	•	Asset Optimization — Represents derivative activity associated with assets owned and contracted by DTE Energy, including forward natural gas purchases and sales, natural gas transportation and storage capacity. Changes in the value of derivatives in this category typically economically offset changes in the value of underlying non-derivative positions, which do not qualify for fair value accounting. The difference in accounting treatment of derivatives in this category and the underlying non-derivative positions can result in significant earnings volatility.
	•	Marketing and Origination — Represents derivative activity transacted by originating substantially hedged positions with wholesale energy marketers, producers, end users, utilities, retail aggregators and alternative energy suppliers.
	•	Fundamentals Based Trading — Represents derivative activity transacted with the intent of taking a view, capturing market price changes, or putting capital at risk. This activity is speculative in nature as opposed to hedging an existing exposure.
	•	Other — Includes derivative activity at DTE Electric related to FTRs. Changes in the value of derivative contracts at DTE Electric are recorded as Derivative assets or liabilities, with an offset to Regulatory assets or liabilities as the settlement value of these contracts will be included in the PSCR mechanism when realized.
	The following tables present the fair value of derivative instruments as of December 31, 2014 and 2013:
		December 31, 2014								December 31, 2013
		Derivative				Derivative Liabilities				Derivative			Derivative Liabilities
		Assets								Assets
		(In millions)
	Derivatives not designated as hedging instruments:
	Foreign currency exchange contracts	$	4			$	(5	)		$	—		$	(1	)
	Commodity Contracts:
	Natural Gas	787				(718		)		396			(503		)
	Electricity	342				(342		)		400			(398		)
	Other	45				(45		)		37			(34		)
	Total derivatives not designated as hedging instruments:	$	1,178			$	(1,110	)		$	833		$	(936	)
	Total derivatives:
	Current	$	1,083			$	(1,041	)		$	691		$	(773	)
	Noncurrent	95				(69		)		142			(163		)
	Total derivatives	$	1,178			$	(1,110	)		$	833		$	(936	)
	Certain of the Company's derivative positions are subject to netting arrangements which provide for offsetting of asset and liability positions as well as related cash collateral. Such netting arrangements generally do not have restrictions. Under such netting arrangements, the Company offsets the fair value of derivative instruments with cash collateral received or paid for those contracts executed with the same counterparty, which reduces the Company's total assets and liabilities. Cash collateral is allocated between the fair value of derivative instruments and customer accounts receivable and payable with the same counterparty on a pro rata basis to the extent there is exposure. Any cash collateral remaining, after the exposure is netted to zero, is reflected in accounts receivable and accounts payable as collateral paid or received, respectively.
	The Company also provides and receives collateral in the form of letters of credit which can be offset against net derivative assets and liabilities as well as accounts receivable and payable. The Company had issued letters of credit of approximately $7 million and $19 million at December 31, 2014 and 2013, respectively, which could be used to offset net derivative liabilities. Letters of credit received from third parties which could be used to offset our net derivative assets were approximately $5 million and $1 million at December 31, 2014 and 2013, respectively. Such balances of letters of credit are excluded from the tables below and are not netted with the recognized assets and liabilities in the Consolidated Statements of Financial Position.
	For contracts with certain clearing agents the fair value of derivative instruments is netted against realized positions with the net balance reflected as either 1) a derivative asset or liability or 2) an account receivable or payable. Other than certain clearing agents, accounts receivable and accounts payable that are subject to netting arrangements have not been offset against the fair value of derivative assets and liabilities. Certain contracts that have netting arrangements have not been offset in the Consolidated Statements of Financial Position. The impact of netting these derivative instruments and cash collateral related to such contracts is not material. Only the gross amounts for these derivative instruments are included in the table below.
	The total cash collateral posted, net of cash collateral received, was $61 million and $12 million as of December 31, 2014 and 2013, respectively. There was no cash collateral related to unrealized positions to net against derivative assets while derivative liabilities are shown net of cash collateral of $19 million as of December 31, 2014. As of December 31, 2013, derivative assets and derivative liabilities are shown net of cash collateral of $26 million and $17 million, respectively. The Company recorded cash collateral paid of $44 million and cash collateral received of $2 million not related to unrealized derivative positions as of December 31, 2014. The Company recorded cash collateral paid of $34 million and cash collateral received of $13 million not related to unrealized derivative positions as of December 31, 2013. These amounts are included in accounts receivable and accounts payable and are recorded net by counterparty.
	The following table presents the netting offsets of derivative assets and liabilities at December 31, 2014 and 2013:
		31-Dec-14											31-Dec-13
		Gross Amounts of Recognized Assets (Liabilities)				Gross Amounts Offset in the Consolidated Statements of Financial Position				Net Amounts of Assets (Liabilities) Presented in the Consolidated Statements of Financial Position			Gross Amounts of Recognized Assets (Liabilities)			Gross Amounts Offset in the Consolidated Statements of Financial Position			Net Amounts of Assets (Liabilities) Presented in the Consolidated Statements of Financial Position
		(In millions)
	Derivative assets:
	Commodity Contracts:
	Natural Gas	$	787			$	(681	)		$	106		$	396		$	(382	)	$	14
	Electricity	342				(280		)		62			400			(291		)	109
	Other	45				(42		)		3			37			(34		)	3
	Other derivative contracts (a)	4				(3		)		1			—			—			—
	Total derivative assets	$	1,178			$	(1,006	)		$	172		$	833		$	(707	)	$	126
	Derivative liabilities:
	Commodity Contracts:
	Natural Gas	$	(718	)		$	679			$	(39	)	$	(503	)	$	395		$	(108	)
	Electricity	(342		)		298				(44		)	(398		)	269			(129		)
	Other	(45		)		45				—			(34		)	34			—
	Other derivative contracts (a)	(5		)		3				(2		)	(1		)	—			(1		)
	Total derivative liabilities	$	(1,110	)		$	1,025			$	(85	)	$	(936	)	$	698		$	(238	)
	_______________________________________
	(a)	Primarily includes Foreign currency exchange contracts
	The following table presents the netting offsets of derivative assets and liabilities at December 31, 2014 and 2013:
		December 31, 2014														31-Dec-13
		Derivative Assets								Derivative Liabilities						Derivative Assets						Derivative Liabilities
		Current				Noncurrent				Current			Noncurrent			Current			Noncurrent			Current			Noncurrent
		(In millions)
	Reconciliation of derivative instruments to Consolidated Statements of Financial Position:
	Total fair value of derivatives	$	1,083			$	95			$	(1,041	)	$	(69	)	$	691		$	142		$	(773	)	$	(163	)
Counterparty netting	(955		)		(51		)		955			51			(566		)	(115		)	566			115
Collateral adjustment	—				—				9			10			(26		)	—			12			5
Total derivatives as reported	$	128			$	44			$	(77	)	$	(8	)	$	99		$	27		$	(195	)	$	(43	)
The effect of derivatives not designated as hedging instruments on the Consolidated Statements of Operations for years ended December 31, 2014 and 2013 is as follows:
		Location of Gain (Loss) Recognized in Income on Derivatives		Gain (Loss) Recognized in
				Income on Derivatives for
				Years Ended December 31,
Derivatives not Designated as Hedging Instruments				2014				2013
				(In millions)
Foreign currency exchange contracts		Operating Revenue		$	(2	)		$	(1	)
Commodity Contracts:
Natural Gas		Operating Revenue		(30		)		(48		)
Natural Gas		Fuel, purchased power and gas		(5		)		(44		)
Electricity		Operating Revenue		123				82
Other		Operating Revenue		(7		)		—
Total				$	79			$	(11	)
Revenues and energy costs related to trading contracts are presented on a net basis in the Consolidated Statements of Operations. Commodity derivatives used for trading purposes, and financial non-trading commodity derivatives, are accounted for using the MTM method with unrealized and realized gains and losses recorded in Operating revenues. Non-trading physical commodity sale and purchase derivative contracts are generally accounted for using the MTM method with unrealized and realized gains and losses for sales recorded in Operating revenue and purchases recorded in Fuel, purchased power and gas.
The following represents the cumulative gross volume of derivative contracts outstanding as of December 31, 2014:
Commodity		Number of Units
Natural Gas (MMBtu)		895,599,953
Electricity (MWh)		11,296,153
Foreign Currency Exchange (Canadian dollars)		63,022,462
Various subsidiaries of the Company have entered into contracts which contain ratings triggers and are guaranteed by DTE Energy. These contracts contain provisions which allow the counterparties to require that the Company post cash or letters of credit as collateral in the event that DTE Energy’s credit rating is downgraded below investment grade. Certain of these provisions (known as “hard triggers”) state specific circumstances under which the Company can be required to post collateral upon the occurrence of a credit downgrade, while other provisions (known as “soft triggers”) are not as specific. For contracts with soft triggers, it is difficult to estimate the amount of collateral which may be requested by counterparties and/or which the Company may ultimately be required to post. The amount of such collateral which could be requested fluctuates based on commodity prices (primarily natural gas, power and coal) and the provisions and maturities of the underlying transactions. As of December 31, 2014, DTE Energy's contractual obligation to post collateral in the form of cash or letter of credit in the event of a downgrade to below investment grade, under both hard trigger and soft trigger provisions, was approximately $349 million.
As of December 31, 2014, the Company had approximately $1,058 million of derivatives in net liability positions, for which hard triggers exist. Collateral of approximately $12 million has been posted against such liabilities, including cash and letters of credit. Associated derivative net asset positions for which contractual offset exists were approximately $973 million. The net remaining amount of approximately $73 million is derived from the $349 million noted above.

LongTerm_Debt_Notes

Long-Term Debt (Notes)	12 Months Ended
	Dec. 31, 2014
Long-term Debt, Unclassified [Abstract]
Long-Term Debt	LONG-TERM DEBT
	Long-Term Debt
	The Company’s long-term debt outstanding and weighted average interest rates (a) of debt outstanding at December 31 were:
		2014				2013
		(In millions)
	Mortgage bonds, notes and other
	DTE Energy Debt, Unsecured
	4.6% due 2016 to 2033	$	1,647			$	1,297
	DTE Electric Taxable Debt, Principally Secured
	4.5% due 2016 to 2044	4,824				4,286
	DTE Electric Tax-Exempt Revenue Bonds (b)
	5.2% due 2020 to 2030	330				558
	DTE Gas Taxable Debt, Principally Secured
	5.2% due 2015 to 2044	1,099				1,029
	Other Long-Term Debt, Including Non-Recourse Debt	121				142
		8,021				7,312
	Less amount due within one year	(161		)		(694		)
		$	7,860			$	6,618
	Securitization bonds
	6.6% due 2015	$	105			$	302
	Less amount due within one year	(105		)		(197		)
		$	—			$	105
	Junior Subordinated Debentures
	6.5% due 2061	$	280			$	280
	5.25% due 2062	200				200
		$	480			$	480
	_______________________________________
	(a)	Weighted average interest rates as of December 31, 2014 are shown below the description of each category of debt.
	(b)	DTE Electric Tax-Exempt Revenue Bonds are issued by a public body that loans the proceeds to DTE Electric on terms substantially mirroring the Revenue Bonds.
	Debt Issuances
	In 2014, the following debt was issued:
	Company		Month Issued		Type		Interest Rate		Maturity		Amount
											(In millions)
	DTE Energy		May		Senior Notes (a)		3.5	%	2024		$	350
	DTE Electric		June		Mortgage Bonds (a)		3.77	%	2026		100
	DTE Electric		June		Mortgage Bonds (a)		4.6	%	2044		150
	DTE Electric		July		Mortgage Bonds (a)		3.375	%	2025		350
	DTE Electric		July		Mortgage Bonds (a)		4.3	%	2044		350
	DTE Energy		November		Senior Notes (a)		2.4	%	2019		300
	DTE Gas		December		Mortgage Bonds (a)		4.35	%	2044		150
											$	1,750
	_______________________________________
	(a)	Proceeds were used for the redemption of long-term debt, repayment of short-term borrowings and general corporate purposes.
	Debt Redemptions
	In 2014, the following debt was redeemed:
	Company		Month		Type		Interest Rate		Maturity		Amount
											(In millions)
	DTE Electric		March		Mortgage Bonds		Various		2014		$	13
	DTE Electric		March		Securitization Bonds		6.62	%	2014		100
	DTE Electric		April		Tax Exempt Revenue Bonds (a)		2.35	%	2024		31
	DTE Electric		April		Tax Exempt Revenue Bonds (a)		4.65	%	2028		32
	DTE Gas		May		Mortgage Bonds		8.25	%	2014		80
	DTE Energy		May		Senior Notes		7.625	%	2014		300
	DTE Electric		June		Tax Exempt Revenue Bonds (a)		4.875	%	2029		36
	DTE Electric		June		Tax Exempt Revenue Bonds (a)		6	%	2036		69
	DTE Electric		July		Senior Notes		4.8	%	2015		200
	DTE Electric		August		Senior Notes		5.4	%	2014		200
	DTE Electric		August		Tax Exempt Revenue Bonds (a)		5.25	%	2029		60
	DTE Electric		September		Securitization Bonds		6.62	%	2014		96
	DTE Energy		Various		Other Long Term Debt		Various		2014		20
											$	1,237
	_______________________________________
	(a)	DTE Electric Tax Exempt Revenue Bonds are issued by a public body that loans the proceeds to DTE Electric on terms substantially mirroring the Revenue Bonds.
	The following table shows the scheduled debt maturities, excluding any unamortized discount or premium on debt:
	2015				2016			2017				2018		2019		2020 and Thereafter		Total
	(In millions)
Amount to mature	$	266			$	465		$	9			$	407	$	427	$	7,046	$	8,620
Junior Subordinated Debentures
At December 31, 2014, DTE Energy had $280 million of 6.5% Junior Subordinated Debentures due 2061 and $200 million of 5.25% Junior Subordinated Debentures due 2062. DTE Energy has the right to defer interest payments on the debt securities. Should DTE Energy exercise this right, it cannot declare or pay dividends on, or redeem, purchase or acquire, any of its capital stock during the deferral period. Any deferred interest payments will bear additional interest at the rate associated with the related debt issue. As of December 31, 2014, no interest payments have been deferred on the debt securities.
Cross Default Provisions
Substantially all of the net utility properties of DTE Electric and DTE Gas are subject to the lien of mortgages. Should DTE Electric or DTE Gas fail to timely pay their indebtedness under these mortgages, such failure may create cross defaults in the indebtedness of DTE Energy.

Preferred_and_Preferenced_Secu

Preferred and Preferenced Securities (Notes)	12 Months Ended
	Dec. 31, 2014
Preferred Stock, Number of Shares, Par Value and Other Disclosures [Abstract]
Preferred and Preference Securities	PREFERRED AND PREFERENCE SECURITIES
	As of December 31, 2014, the amount of authorized and unissued stock is as follows:
	Company	Type of Stock	Par Value		Shares Authorized
	DTE Energy	Preferred	$	—	5,000,000
	DTE Electric	Preferred	$	100	6,747,484
	DTE Electric	Preference	$	1	30,000,000
	DTE Gas	Preferred	$	1	7,000,000
	DTE Gas	Preference	$	1	4,000,000

ShortTerm_Credit_Arrangements_

Short-Term Credit Arrangements and Borrowings (Notes)	12 Months Ended
	Dec. 31, 2014
Short-term Debt [Abstract]
Short-Term Credit Arrangements and Borrowings	SHORT-TERM CREDIT ARRANGEMENTS AND BORROWINGS
	DTE Energy and its wholly owned subsidiaries, DTE Electric and DTE Gas, have unsecured revolving credit agreements that can be used for general corporate borrowings, but are intended to provide liquidity support for each of the companies’ commercial paper programs. Borrowings under the facilities are available at prevailing short-term interest rates. Additionally, DTE Energy has other facilities to support letter of credit issuance.
	The agreements require the Company to maintain a total funded debt to capitalization ratio of no more than 0.65 to 1. At December 31, 2014, the total funded debt to total capitalization ratios for DTE Energy, DTE Electric and DTE Gas are 0.50 to 1, 0.51 to 1 and 0.48 to 1, respectively, and are in compliance with this financial covenant. The availability under the facilities in place at December 31, 2014 is shown in the following table:
		DTE Energy		DTE Electric		DTE Gas		Total
		(In millions)
	Unsecured letter of credit facility, expiring in February 2015	$	100	$	—	$	—	$	100
	Unsecured letter of credit facility, expiring in August 2015	125		—		—		125
	Unsecured revolving credit facility, expiring April 2018	1,200		300		300		1,800
		1,425		300		300		2,025
	Amounts outstanding at December 31, 2014:
	Commercial paper issuances	203		50		145		398
	Letters of credit	204		—		—		204
		407		50		145		602
	Net availability at December 31, 2014	$	1,018	$	250	$	155	$	1,423
	The Company has other outstanding letters of credit which are not included in the above described facilities totaling approximately $35 million which are used for various corporate purposes.
	The weighted average interest rate for short-term borrowings was 0.4% and 0.2% at December 31, 2014 and 2013, respectively.
	In conjunction with maintaining certain exchange traded risk management positions, the Company may be required to post cash collateral with its clearing agent. The Company has a demand financing agreement for up to $100 million with its clearing agent. The agreement, as amended, also allows for up to $50 million of additional margin financing provided that the Company posts a letter of credit for the incremental amount. At December 31, 2014, a $50 million letter of credit was in place, raising the capacity under this facility to $150 million. The $50 million letter of credit is included in the table above. The amount outstanding under this agreement was $37 million and $138 million at December 31, 2014 and 2013, respectively.
	Dividend Restrictions
	Certain of the Company’s credit facilities contain a provision requiring the Company to maintain a total funded debt to capitalization ratio, as defined in the agreements, of no more than 0.65 to 1, which has the effect of limiting the amount of dividends the Company can pay in order to maintain compliance with this provision. The effect of this provision was to restrict the payment of approximately $730 million at December 31, 2014 of total retained earnings of approximately $4.6 billion. There are no other effective limitations with respect to the Company’s ability to pay dividends.

Capital_and_Operating_Leases_N

Capital and Operating Leases (Notes)	12 Months Ended
	Dec. 31, 2014
Leases [Abstract]
Capital and Operating Leases	CAPITAL AND OPERATING LEASES
	Lessee  - Operating Lease — The Company leases various assets under operating leases, including coal railcars, office buildings, a warehouse, computers, vehicles and other equipment. The lease arrangements expire at various dates through 2046.
	Future minimum lease payments under non-cancelable leases at December 31, 2014 were:
		Operating
		Leases
		(In millions)
	2015	$	42
	2016	34
	2017	28
	2018	23
	2019	14
	Thereafter	78
	Total minimum lease payments	$	219
	Rental expense for operating leases was $38 million in 2014, $34 million in 2013 and $36 million in 2012.
	Lessor - Capital Lease — The Company leases a portion of its pipeline system to the Vector Pipeline through a capital lease contract that expires in 2020, with renewal options extending for five years. The Company owns a 40% interest in the Vector Pipeline. In addition, the Company has two energy services agreements, a portion of which are accounted for as capital leases. One agreement expires in 2021. The other agreement expires in 2019, with a three or five year renewal option. The components of the net investment in the capital leases at December 31, 2014, were as follows:
		Capital
		Leases
		(In millions)
	2015	$	12
	2016	13
	2017	13
	2018	13
	2019	10
	Thereafter	9
	Total minimum future lease receipts	70
	Residual value of leased pipeline	40
	Less unearned income	(34		)
	Net investment in capital lease	76
	Less current portion	(5		)
		$	71

Commitments_and_Contingencies_

Commitments and Contingencies (Notes)	12 Months Ended
	Dec. 31, 2014
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	COMMITMENTS AND CONTINGENCIES
	Environmental
	Electric
	Air — DTE Electric is subject to the EPA ozone and fine particulate transport and acid rain regulations that limit power plant emissions of sulfur dioxide and nitrogen oxides. The EPA and the State of Michigan have issued emission reduction regulations relating to ozone, fine particulate, regional haze, mercury, and other air pollution. These rules have led to controls on fossil-fueled power plants to reduce nitrogen oxide, sulfur dioxide, mercury and other emissions. To comply with these requirements, DTE Electric spent approximately $2.2 billion through 2014. The Company estimates DTE Electric will make capital expenditures of approximately $100 million in 2015 and up to approximately $30 million of additional capital expenditures through 2019 based on current regulations.
	Additional rulemakings are expected over the next few years which could require additional controls for sulfur dioxide, nitrogen oxides and other hazardous air pollutants. The Cross State Air Pollution Rule (CSAPR), requires further reductions of sulfur dioxide and nitrogen oxides emissions effective January 2015. DTE Electric expects to meet its obligations under CSAPR beginning in 2015.
	The Mercury and Air Toxics Standard (MATS) rule, formerly known as the Electric Generating Unit Maximum Achievable Control Technology (EGU MACT) Rule was finalized in December 2011. The MATS rule requires reductions of mercury and other hazardous air pollutants beginning in April 2015, with a potential extension to April 2016. DTE Electric has requested and been granted compliance date extensions for all relevant units to April 2016. DTE Electric has tested technologies to determine technological and economic feasibility as MATS compliance alternatives to Flue Gas Desulfurization (FGD) systems. Implementation of Dry Sorbent Injection (DSI) and Activated Carbon Injection (ACI) technologies will allow several units that would not have been economical for FGD installations to continue operation in compliance with MATS. In November 2014, the Supreme Court agreed to review a challenge to the MATS rule based on a narrowly focused question of how the EPA considered costs in regulating air pollutants emitted by electric utilities. DTE Electric cannot predict the financial impact or outcome of this Supreme Court case, or the timing of its resolution.
	The EPA proposed revised air quality standards for ground level ozone in November 2014 and the standards are expected to be finalized by October 2015. DTE Electric will engage with the EPA and other stakeholders in commenting on this rule. DTE Electric cannot predict the financial impact of the proposed ozone standards at this time.
	In July 2009, DTE Energy received a NOV/FOV from the EPA alleging, among other things, that five DTE Electric power plants violated New Source Performance standards, Prevention of Significant Deterioration requirements, and operating permit requirements under the Clean Air Act. In June 2010, the EPA issued a NOV/FOV making similar allegations related to a project and outage at Unit 2 of the Monroe Power Plant. In March 2013, DTE Energy received a supplemental NOV from the EPA relating to the July 2009 NOV/FOV. The supplemental NOV alleged additional violations relating to the New Source Review provisions under the Clean Air Act, among other things.
	In August 2010, the U.S. Department of Justice, at the request of the EPA, brought a civil suit in the U.S. District Court for the Eastern District of Michigan against DTE Energy and DTE Electric, related to the June 2010 NOV/FOV and the outage work performed at Unit 2 of the Monroe Power Plant, but not relating to the July 2009 NOV/FOV. Among other relief, the EPA requested the court to require DTE Electric to install and operate the best available control technology at Unit 2 of the Monroe Power Plant. Further, the EPA requested the court to issue a preliminary injunction to require DTE Electric to (i) begin the process of obtaining the necessary permits for the Monroe Unit 2 modification and (ii) offset the pollution from Monroe Unit 2 through emissions reductions from DTE Electric's fleet of coal-fired power plants until the new control equipment is operating. In August 2011, the U.S. District Court judge granted DTE Energy's motion for summary judgment in the civil case, dismissing the case and entering judgment in favor of DTE Energy and DTE Electric. In October 2011, the EPA caused to be filed a Notice of Appeal to the U.S. Court of Appeals for the Sixth Circuit. In March 2013, the Court of Appeals remanded the case to the U.S. District Court for review of the procedural component of the New Source Review notification requirements. In September 2013, the EPA caused to be filed a motion seeking leave to amend their complaint regarding the June 2010 NOV/FOV adding additional claims related to outage work performed at the Trenton Channel and Belle River power plants as well as additional claims related to work performed at the Monroe Power Plant. In addition, the Sierra Club caused to be filed a motion to add a claim regarding the River Rouge Power Plant. In March 2014, the U.S. District Court judge granted again DTE Energy's motion for summary judgment dismissing the civil case related to Monroe Unit 2. In April 2014, the U.S. District Court judge granted motions filed by the EPA and the Sierra Club to amend their New Source Review complaint adding additional claims for Monroe Units 1, 2 and 3, Belle River Units 1 and 2, Trenton Channel Unit 9 and denied the claims related to River Rouge that were brought by the Sierra Club. In June 2014, the EPA filed a motion requesting certification for appeal of the March 2014 summary judgment decision. In October 2014, the EPA and the U.S. Department of Justice filed the anticipated notice of appeal of the U.S. District Court judge's dismissal of the Monroe Unit 2 case. This will officially start the appellate process. The amended New Source Review claims are all stayed until the appeal is resolved by the U.S. Court of Appeals for the Sixth Circuit.
	DTE Energy and DTE Electric believe that the plants and generating units identified by the EPA and the Sierra Club have complied with all applicable federal environmental regulations. Depending upon the outcome of discussions with the EPA regarding the two NOVs/FOVs, DTE Electric could be required to install additional pollution control equipment at some or all of the power plants in question, implement early retirement of facilities where control equipment is not economical, engage in supplemental environmental programs, and/or pay fines. The Company cannot predict the financial impact or outcome of this matter, or the timing of its resolution.
	Water — In response to an EPA regulation, DTE Electric would be required to examine alternatives for reducing the environmental impacts of the cooling water intake structures at several of its facilities. Based on the results of completed studies and expected future studies, DTE Electric may be required to install technologies to reduce the impacts of the water intake structures. A final rule was issued in May 2014. The final rule specifies a time period exceeding three years to complete studies to determine the type of technology needed to reduce impacts to fish. Final compliance for the installation of the required technology will be determined by each state on a case by case basis. We are currently evaluating the compliance options and working with the State of Michigan on evaluating whether any controls are needed. These evaluations/studies may require modifications to some existing intake structures. It is not possible to quantify the impact of this rulemaking at this time.
	In April 2013, the EPA proposed revised steam electric effluent guidelines regulating wastewater streams from coal-fired power plants including multiple possible options for compliance. The rules are expected to be finalized by September 2015. It is not possible at this time to quantify the impacts of these developing requirements.
	Contaminated and Other Sites — Prior to the construction of major interstate natural gas pipelines, gas for heating and other uses was manufactured locally from processes involving coal, coke or oil. The facilities, which produced gas, have been designated as MGP sites. DTE Electric conducted remedial investigations at contaminated sites, including three former MGP sites. The investigations have revealed contamination related to the by-products of gas manufacturing at each MGP site. In addition to the MGP sites, the Company is also in the process of cleaning up other contaminated sites, including the area surrounding an ash landfill, electrical distribution substations, electric generating power plants, and underground and aboveground storage tank locations. The findings of these investigations indicated that the estimated cost to remediate these sites is expected to be incurred over the next several years. At December 31, 2014 and 2013, the Company had $10 million and $8 million accrued for remediation, respectively. Any change in assumptions, such as remediation techniques, nature and extent of contamination and regulatory requirements, could impact the estimate of remedial action costs for the sites and affect the Company’s financial position and cash flows. The Company believes the likelihood of a material change to the accrued amount is remote based on current knowledge of the conditions at each site.
	In December 2014, the EPA released a pre-publication version of a rule to regulate coal ash. This rule is based on the continued listing of ash as a non-hazardous waste, and relies on various self-implementation design and performance standards. The rule is still being evaluated and it is not possible to quantify its impact at this time. DTE Electric owns and operates three permitted engineered ash storage facilities to dispose of fly ash from coal fired power plants and operates a number of smaller impoundments at its power plants.
	Gas
	Contaminated and Other Sites — Gas segment, owns or previously owned, 15 former MGP sites. Investigations have revealed contamination related to the by-products of gas manufacturing at each site. Cleanup of three of the MGP sites is complete and the sites were closed. We completed partial closure of two sites in 2014. Cleanup activities associated with the remaining sites will be continued over the next several years. The MPSC has established a cost deferral and rate recovery mechanism for investigation and remediation costs incurred at former MGP sites. In addition to the MGP sites, the Company is also in the process of cleaning up other contaminated sites, including gate stations, gas pipeline releases and underground storage tank locations. As of December 31, 2014 and 2013, the Company had $24 million and $28 million accrued for remediation, respectively. Any change in assumptions, such as remediation techniques, nature and extent of contamination and regulatory requirements, could impact the estimate of remedial action costs for the sites and affect the Company’s financial position and cash flows. The Company anticipates the cost amortization methodology approved by the MPSC for DTE Gas, which allows DTE Gas to amortize the MGP costs over a ten-year period beginning with the year subsequent to the year the MGP costs were incurred, will prevent environmental costs from having a material adverse impact on the Company’s results of operations.
	Non-utility
	The Company’s non-utility businesses are subject to a number of environmental laws and regulations dealing with the protection of the environment from various pollutants.
	The Michigan coke battery facility received and responded to information requests from the EPA that resulted in the issuance of a NOV in June 2007 alleging potential maximum achievable control technologies and new source review violations. The EPA is in the process of reviewing the Company’s position of demonstrated compliance and has not initiated escalated enforcement. At this time, the Company cannot predict the impact of this issue. Furthermore, the Michigan coke battery facility is the subject of an investigation by the MDEQ concerning visible emissions readings that resulted from the Company self reporting to MDEQ questionable activities by an employee of a contractor hired by the Company to perform the visible emissions readings. At this time, the Company cannot predict the impact of this investigation.
	The Company received two NOVs from the Pennsylvania Department of Environmental Protection (PADEP) in 2010 alleging violations of the permit for the Pennsylvania coke battery facility in connection with coal pile storm water runoff. The Company settled the alleged violations by implementing best management practices to address the issues and repair/upgrade their wastewater treatment plant. The Company recently received a permit to upgrade its existing waste water treatment system and is currently seeking a permit from the PADEP to further upgrade its wastewater treatment technology to a biological treatment facility. The Company expects to spend $1 million on the existing waste water treatment system to comply with existing water discharge requirements and to upgrade its coal pile storm water runoff management program. The Company will also spend up to an additional $13 million over the next few years to upgrade the treatment technology to biological treatment to meet future regulatory requirements and gain other operational improvement savings.
	The Company received an NOV from the Allegheny County (PA) Health Department pertaining to excessive opacity readings from fugitive sources (mainly pushing emissions) in excess of its opacity standards for the Pennsylvania coke battery facility. Fugitive sources at the plant are in full compliance with the applicable Federal Opacity Standards. In February 2014, the Company received from the Group Against Smog & Pollution (GASP) a 60 day Notice of Intent to sue letter under the Federal Clean Air Act and/or Article XXI of the Allegheny County (PA) Health Department's Rules and Regulations. GASP alleged in the letter that the Company's coke battery facility in Pennsylvania was in violation of visible emissions limits from charging activities, door leaks, the combustion stack and pushing operations and hydrogen sulfide emission limits on flared, mixed or combusted coke oven gas. To resolve these issues, the Company agreed to a Consent Order and Agreement with Allegheny County pursuant to which the Company paid a fine of $300,000 and will spend $300,000 for a supplemental environmental project to enhance particulate collection efficiency from the coke battery's quench tower. Notwithstanding the agreement reached with the County, GASP proceeded with the filing of their complaint in May 2014. The Company believes that the GASP suit is without merit and filed a motion to dismiss in July 2014.
	Other
	In 2010, the EPA finalized a new 1-hour sulfur dioxide ambient air quality standard that requires states to submit plans for non-attainment areas to be in compliance by 2017. Michigan's non-attainment area includes DTE Energy facilities in southwest Detroit and areas of Wayne County. Preliminary modeling runs by the MDEQ suggest that emission reductions may be required by significant sources of sulfur dioxide emissions in these areas, including DTE Electric power plants and our Michigan coke battery. The state implementation plan process is in the information gathering stage, and DTE Energy is unable to estimate any required emissions reductions at this time.
	Nuclear Operations
	Property Insurance
	DTE Electric maintains property insurance policies specifically for the Fermi 2 plant. These policies cover such items as replacement power and property damage. NEIL is the primary supplier of the insurance policies.
	DTE Electric maintains a policy for extra expenses, including replacement power costs necessitated by Fermi 2’s unavailability due to an insured event. This policy has a 12-week waiting period and provides an aggregate $490 million of coverage over a three-year period.
	DTE Electric has $1.5 billion in primary coverage and $1.25 billion of excess coverage for stabilization, decontamination, debris removal, repair and/or replacement of property and decommissioning. The combined coverage limit for total property damage is $2.75 billion, subject to a $1 million deductible. The total limit for property damage for non-nuclear events is $2 billion and an aggregate of $328 million of coverage for extra expenses over a two-year period.
	On January 13, 2015, the Terrorism Risk Insurance Program Reauthorization Act of 2015 was signed, extending TRIA through December 31, 2020. For multiple terrorism losses caused by acts of terrorism not covered under the TRIA occurring within one year after the first loss from terrorism, the NEIL policies would make available to all insured entities up to $3.2 billion, plus any amounts recovered from reinsurance, government indemnity, or other sources to cover losses.
	Under NEIL policies, DTE Electric could be liable for maximum assessments of up to approximately $35 million per event if the loss associated with any one event at any nuclear plant should exceed the accumulated funds available to NEIL.
	Public Liability Insurance
	As required by federal law, DTE Electric maintains $375 million of public liability insurance for a nuclear incident. For liabilities arising from a terrorist act outside the scope of TRIA, the policy is subject to one industry aggregate limit of $300 million. Further, under the Price-Anderson Amendments Act of 2005, deferred premium charges up to $127 million could be levied against each licensed nuclear facility, but not more than $19 million per year per facility. Thus, deferred premium charges could be levied against all owners of licensed nuclear facilities in the event of a nuclear incident at any of these facilities.
	Nuclear Fuel Disposal Costs
	In accordance with the Federal Nuclear Waste Policy Act of 1982, DTE Electric has a contract with the DOE for the future storage and disposal of spent nuclear fuel from Fermi 2 that required DTE Electric to pay the DOE a fee of 1 mill per kWh of Fermi 2 electricity generated and sold. The fee was a component of nuclear fuel expense. The DOE's Yucca Mountain Nuclear Waste Repository program for the acceptance and disposal of spent nuclear fuel was terminated in 2011. DTE Electric is a party in the litigation against the DOE for both past and future costs associated with the DOE's failure to accept spent nuclear fuel under the timetable set forth in the Federal Nuclear Waste Policy Act of 1982. In July 2012, DTE Electric executed a settlement agreement with the federal government for costs associated with the DOE's delay in acceptance of spent nuclear fuel from Fermi 2 for permanent storage. The settlement agreement, including extensions, provides for a claims process and payment of delay-related costs experienced by DTE Electric through 2016. DTE Electric's claims are being settled and paid on a timely basis. The settlement proceeds reduce the cost of the dry cask storage facility assets and provide reimbursement for related operating expenses. The 1 mill per kWh DOE fee was reduced to zero effective May 16, 2014.
	DTE Electric currently employs a spent nuclear fuel storage strategy utilizing a fuel pool and a newly completed dry cask storage facility. The initial dry cask loading campaign planned for 2014 has been completed. The dry cask storage facility is expected to provide sufficient spent fuel storage capability for the life of the plant as defined by the original operating license.
	The federal government continues to maintain its legal obligation to accept spent nuclear fuel from Fermi 2 for permanent storage. Issues relating to long-term waste disposal policy and to the disposition of funds contributed by DTE Electric ratepayers to the federal waste fund await future governmental action.
	Synthetic Fuel Guarantees
	The Company discontinued the operations of its synthetic fuel production facilities throughout the United States as of December 31, 2007. The Company provided certain guarantees and indemnities in conjunction with the sales of interests in its synfuel facilities. The guarantees cover potential commercial, environmental, oil price and tax-related obligations and will survive until 90 days after expiration of all applicable statutes of limitations. The Company estimates that its maximum potential liability under these guarantees at December 31, 2014 is approximately $1 billion. Payment under these guarantees is considered remote.
	REF Guarantees
	The Company has provided certain guarantees and indemnities in conjunction with the sales of interests in its REF facilities. The guarantees cover potential commercial, environmental, and tax-related obligations and will survive until 90 days after expiration of all applicable statutes of limitations. The Company estimates that its maximum potential liability under these guarantees at December 31, 2014 is approximately $172 million. Payment under these guarantees is considered remote.
	Other Guarantees
	In certain limited circumstances, the Company enters into contractual guarantees. The Company may guarantee another entity’s obligation in the event it fails to perform. The Company may provide guarantees in certain indemnification agreements. Finally, the Company may provide indirect guarantees for the indebtedness of others. The Company’s guarantees are not individually material with maximum potential payments totaling $60 million at December 31, 2014. Payment under these guarantees is considered remote.
	The Company is periodically required to obtain performance surety bonds in support of obligations to various governmental entities and other companies in connection with its operations. As of December 31, 2014, the Company had approximately $49 million of performance bonds outstanding. In the event that such bonds are called for nonperformance, the Company would be obligated to reimburse the issuer of the performance bond. The Company is released from the performance bonds as the contractual performance is completed and does not believe that a material amount of any currently outstanding performance bonds will be called.
	Labor Contracts
	There are several bargaining units for the Company's approximately 4,900 represented employees. The majority of the represented employees are under contracts that expire in 2016 and 2017.
	Purchase Commitments
	As of December 31, 2014, the Company was party to numerous long-term purchase commitments relating to a variety of goods and services required for the Company’s business. These agreements primarily consist of fuel supply commitments, renewable energy contracts and energy trading contracts. The Company estimates that these commitments will be approximately $9.0 billion from 2015 through 2051 as detailed in the following table:
		(In millions)
	2015	$	2,384
	2016	1,258
	2017	742
	2018	477
	2019	431
	2020 and thereafter	3,723
		$	9,015
	The Company also estimates that 2015 capital expenditures and contributions to equity method investments will be approximately $2.6 billion. The Company has made certain commitments in connection with expected capital expenditures.
	Bankruptcies
	The Company purchases and sells electricity, natural gas, coal, coke and other energy products from and to governmental entities and numerous companies operating in the steel, automotive, energy, retail, financial and other industries. Certain of its customers have filed for bankruptcy protection under the U.S. Bankruptcy Code. The Company regularly reviews contingent matters relating to these customers and its purchase and sale contracts and records provisions for amounts considered at risk of probable loss. The Company believes its accrued amounts are adequate for probable loss.
	Other Contingencies
	The Company is involved in certain other legal, regulatory, administrative and environmental proceedings before various courts, arbitration panels and governmental agencies concerning claims arising in the ordinary course of business. These proceedings include certain contract disputes, additional environmental reviews and investigations, audits, inquiries from various regulators, and pending judicial matters. The Company cannot predict the final disposition of such proceedings. The Company regularly reviews legal matters and records provisions for claims that it can estimate and are considered probable of loss. The resolution of these pending proceedings is not expected to have a material effect on the Company’s operations or financial statements in the periods they are resolved.
	For a discussion of contingencies related to regulatory matters and derivatives see Notes 8 and 12 to the Consolidated Financial Statements, "Regulatory Matters" and "Financial and Other Derivative Instruments".

Retirement_Benefits_and_Truste

Retirement Benefits and Trusteed Assets (Notes)	12 Months Ended
	Dec. 31, 2014
Defined Benefit Pension Plans and Defined Benefit Postretirement Plans Disclosure [Abstract]
Retirement Benefits and Trusteed Assets	RETIREMENT BENEFITS AND TRUSTEED ASSETS
	Pension Plan Benefits
	The Company has qualified defined benefit retirement plans for eligible represented and non-represented employees. The plans are noncontributory, and provide traditional retirement benefits based on the employees’ years of benefit service, average final compensation and age at retirement. In addition, certain represented and non-represented employees are covered under cash balance provisions that determine benefits on annual employer contributions and interest credits. The Company also maintains supplemental nonqualified, noncontributory, retirement benefit plans for selected management employees. These plans provide for benefits that supplement those provided by DTE Energy’s other retirement plans.
	Effective January 1, 2012 for non-represented employees, and in June 2011 and March 2013 for the majority of represented employees, the Company discontinued offering a defined benefit retirement plan to newly hired employees. In its place, the Company will annually contribute an amount equivalent to 4% (8% for certain DTE Gas represented employees) of an employee's eligible pay to the employee's defined contribution retirement savings plan.
	The Company’s policy is to fund pension costs by contributing amounts consistent with the provisions of the Pension Protection Act of 2006 and additional amounts when it deems appropriate. The Company contributed $188 million to its qualified pension plans in 2014. At the discretion of management, and depending upon financial market conditions, the Company anticipates making up to $180 million in contributions to the pension plans in 2015.
	Net pension cost includes the following components:
		2014			2013			2012
		(In millions)
	Service cost	$	83		$	94		$	82
	Interest cost	212			192			204
	Expected return on plan assets	(273		)	(266		)	(244		)
	Amortization of:
	Net loss	157			208			176
	Special termination benefits	—			—			2
	Net pension cost	$	179		$	228		$	220
		2014			2013
		(In millions)
	Other changes in plan assets and benefit obligations recognized in Regulatory assets and Other comprehensive income
	Net actuarial (gain) loss	$	805		$	(581	)
	Amortization of net actuarial loss	(157		)	(208		)
	Prior service cost	(7		)	—
	Total recognized in Regulatory assets and Other comprehensive income	$	641		$	(789	)
	Total recognized in net periodic pension cost, Regulatory assets and Other comprehensive income	$	820		$	(561	)
	Estimated amounts to be amortized from Regulatory assets and Accumulated other comprehensive income into net periodic benefit cost during next fiscal year
	Net actuarial loss	$	206		$	151
	The following table reconciles the obligations, assets and funded status of the plans as well as the amounts recognized as prepaid pension cost or pension liability in the Consolidated Statements of Financial Position at December 31:
		2014			2013
		(In millions)
	Accumulated benefit obligation, end of year	$	4,853		$	4,068
	Change in projected benefit obligation
	Projected benefit obligation, beginning of year	$	4,380		$	4,729
	Service cost	83			94
	Interest cost	212			192
	Plan amendments	(7		)	(3		)
	Actuarial (gain) loss	836			(400		)
	Benefits paid	(235		)	(232		)
	Projected benefit obligation, end of year	$	5,269		$	4,380
	Change in plan assets
	Plan assets at fair value, beginning of year	$	3,720		$	3,223
	Actual return on plan assets	301			445
	Company contributions	195			284
	Benefits paid	(235		)	(232		)
	Plan assets at fair value, end of year	$	3,981		$	3,720
	Funded status of the plans	$	(1,288	)	$	(660	)
	Amount recorded as:
	Current liabilities	$	(8	)	$	(7	)
	Noncurrent liabilities	(1,280		)	(653		)
		$	(1,288	)	$	(660	)
	Amounts recognized in Accumulated other comprehensive loss, pre-tax
	Net actuarial loss	$	194		$	174
	Prior service (credit)	(1		)	(1		)
		$	193		$	173
	Amounts recognized in Regulatory assets (see Note 8)
	Net actuarial loss	$	2,285		$	1,654
	Prior service (credit) cost	(1		)	6
		$	2,284		$	1,660
	At December 31, 2014, the benefits related to the Company’s qualified and nonqualified pension plans expected to be paid in each of the next five years and in the aggregate for the five fiscal years thereafter are as follows:
		(In millions)
	2015	$	269
	2016	277
	2017	286
	2018	298
	2019	309
	2020-2024	1,634
Total	$	3,073
Assumptions used in determining the projected benefit obligation and net pension costs are listed below:
	2014		2013	2012
Projected benefit obligation
Discount rate	4.12%		4.95%	4.15%
Rate of compensation increase	4.65%		4.20%	4.20%
Net pension costs
Discount rate	4.95%		4.15%	5.00%
Rate of compensation increase	4.20%		4.20%	4.20%
Expected long-term rate of return on plan assets	7.75%		8.25%	8.25%
The Company employs a formal process in determining the long-term rate of return for various asset classes. Management reviews historic financial market risks and returns and long-term historic relationships between the asset classes of equities, fixed income and other assets, consistent with the widely accepted capital market principle that asset classes with higher volatility generate a greater return over the long-term. Current market factors such as inflation, interest rates, asset class risks and asset class returns are evaluated and considered before long-term capital market assumptions are determined. The long-term portfolio return is also established employing a consistent formal process, with due consideration of diversification, active investment management and rebalancing. Peer data is reviewed to check for reasonableness. As a result of this process, the Company has long-term rate of return assumptions for its pension plans of 7.75% and other postretirement benefit plans of 8.00%, for 2015. The Company believes these rates are a reasonable assumption for the long-term rate of return on its plan assets for 2015 given its investment strategy.
The Company employs a total return investment approach whereby a mix of equities, fixed income and other investments are used to maximize the long-term return on plan assets consistent with prudent levels of risk, with consideration given to the liquidity needs of the plan. Risk tolerance is established through consideration of future plan cash flows, plan funded status and corporate financial considerations. The investment portfolio contains a diversified blend of equity, fixed income and other investments. Furthermore, equity investments are diversified across U.S. and non-U.S. stocks, growth and value stocks, and large and small market capitalizations. Fixed income securities generally include market and long duration bonds of companies from diversified industries, mortgage-backed securities, non-U.S. securities, bank loans and U.S. Treasuries. Other assets such as private markets and hedge funds are used to enhance long-term returns while improving portfolio diversification. Derivatives may be utilized in a risk controlled manner, to potentially increase the portfolio beyond the market value of invested assets and/or reduce portfolio investment risk. Investment risk is measured and monitored on an ongoing basis through annual liability measurements, periodic asset/liability studies and quarterly investment portfolio reviews.
Target allocations for pension plan assets as of December 31, 2014 are listed below:
U.S. Large Cap Equity Securities	22	%
U.S. Small Cap and Mid Cap Equity Securities	5
Non U.S. Equity Securities	20
Fixed Income Securities	25
Hedge Funds and Similar Investments	20
Private Equity and Other	8
	100	%
Fair Value Measurements for pension plan assets at December 31, 2014 and 2013 (a):
	December 31, 2014												31-Dec-13
	Level 1			Level 2			Level 3			Total			Level 1			Level 2			Level 3		Total
	(In millions)
Asset category:
Short-term investments (b)	$	46		$	—		$	—		$	46		$	22		$	—		$	—	$	22
Equity securities
U.S. large cap (c)	899			—			—			899			896			—			—		896
U.S. small/mid cap (d)	225			—			—			225			221			—			—		221
Non U.S. (e)	526			219			—			745			611			130			—		741
Fixed income securities (f)	7			1,113			—			1,120			16			921			—		937
Hedge funds and similar investments (g)	226			95			438			759			268			70			395		733
Private equity and other (h)	—			—			187			187			—			—			170		170
Securities lending (i)	(189		)	(50		)	—			(239		)	—			—			—		—
Securities lending collateral (i)	189			50			—			239			—			—			—		—
Total	$	1,929		$	1,427		$	625		$	3,981		$	2,034		$	1,121		$	565	$	3,720
_______________________________________
(a)	For a description of levels within the fair value hierarchy see Note 11 to the Consolidated Financial Statements, "Fair Value".
(b)	This category predominantly represents certain short-term fixed income securities and money market investments that are managed in separate accounts or commingled funds. Pricing for investments in this category are obtained from quoted prices in actively traded markets or valuations from brokers or pricing services.
(c)	This category comprises both actively and not actively managed portfolios that track the S&P 500 low cost equity index funds. Investments in this category are exchange-traded securities whereby unadjusted quote prices can be obtained. Exchange-traded securities held in a commingled fund are classified as Level 2 assets.
(d)	This category represents portfolios of small and medium capitalization domestic equities. Investments in this category are exchange-traded securities whereby unadjusted quote prices can be obtained. Exchange-traded securities held in a commingled fund are classified as Level 2 assets.
(e)	This category primarily consists of portfolios of non-U.S. developed and emerging market equities. Investments in this category are exchange-traded securities whereby unadjusted quote prices can be obtained. Exchange-traded securities held in a commingled fund are classified as Level 2 assets.
(f)	This category includes corporate bonds from diversified industries, U.S. Treasuries, and mortgage-backed securities. Pricing for investments in this category is obtained from quoted prices in actively traded markets and quotations from broker or pricing services. Non-exchange traded securities and exchange-traded securities held in commingled funds are classified as Level 2 assets.
(g)	This category utilizes a diversified group of strategies that attempt to capture financial market inefficiencies and includes publicly traded debt and equity, publicly traded mutual funds, commingled and limited partnership funds and non-exchange traded securities. Pricing for Level 1 and Level 2 assets in this category is obtained from quoted prices in actively traded markets and quoted prices from broker or pricing services. Non-exchange traded securities held in commingled funds are classified as Level 2 assets. Valuations for some Level 3 assets in this category may be based on limited observable inputs as there may be little, if any, publicly available pricing.
(h)	This category includes a diversified group of funds and strategies that primarily invests in private equity partnerships. This category also includes investments in timber and private mezzanine debt. Pricing for investments in this category is based on limited observable inputs as there is little, if any, publicly available pricing. Valuations for assets in this category may be based on discounted cash flow analyses, relevant publicly-traded comparables and comparable transactions.
(i)	In 2014, DTE Energy began a securities lending program with a third party agent. The program allows the agent to lend certain securities from the Company's pension trusts to selected entities against receipt of collateral (in the form of cash) as provided for and determined in accordance with its securities lending agency agreement.
The pension trust holds debt and equity securities directly and indirectly through commingled funds and institutional mutual funds. Exchange-traded debt and equity securities held directly are valued using quoted market prices in actively traded markets. The commingled funds and institutional mutual funds hold exchange-traded equity or debt securities and are valued based on stated NAVs. Non-exchange traded fixed income securities are valued by the trustee based upon quotations available from brokers or pricing services. A primary price source is identified by asset type, class or issue for each security. The trustee monitors prices supplied by pricing services and may use a supplemental price source or change the primary price source of a given security if the trustee challenges an assigned price and determines that another price source is considered to be preferable. DTE Energy has obtained an understanding of how these prices are derived, including the nature and observability of the inputs used in deriving such prices. Additionally, DTE Energy selectively corroborates the fair values of securities by comparison of market-based price sources.
Fair Value Measurements Using Significant Unobservable Inputs (Level 3):
	Year Ended December 31, 2014									Year Ended December 31, 2013
	Hedge Funds			Private Equity			Total			Hedge Funds			Private Equity			Total
	and Similar			and Other						and Similar			and Other
	Investments									Investments
	(In millions)
Beginning Balance at January 1	$	395		$	170		$	565		$	339		$	179		$	518
Total realized/unrealized gains (losses)	22			16			38			40			4			44
Purchases, sales and settlements:
Purchases	22			31			53			16			15			31
Sales	(1		)	(30		)	(31		)	—			(28		)	(28		)
Ending Balance at December 31	$	438		$	187		$	625		$	395		$	170		$	565
The amount of total gains for the period attributable to the change in unrealized gains or losses related to assets still held at the end of the period	$	21		$	11		$	32		$	38		$	3		$	41
There were no transfers between Level 3 and Level 2 and there were no significant transfers between Level 2 and Level 1 in the years ended December 31, 2014 and 2013.
Other Postretirement Benefits
The Company participates in defined benefit plans sponsored by the LLC that provide certain other postretirement health care and life insurance benefits for employees who are eligible for these benefits. The Company’s policy is to fund certain trusts to meet its other postretirement benefit obligations. Separate qualified VEBA and other benefit trusts exist. The Company contributed $24 million to these trusts for its defined benefit other postretirement medical and life insurance benefit plans during 2014. At the discretion of management, the Company anticipates making up to $200 million of contributions to the trusts in 2015.
Starting in 2012, in lieu of offering future employees defined benefit post-employment health care and life insurance benefits, the Company allocates a fixed amount per year to an account in a defined contribution VEBA for each employee. These accounts are managed either by the Company (for non-represented and certain represented groups), or by the Utility Workers of America (UWUA) for Local 223 employees. The contributions to the VEBA for these accounts were $4 million in 2014, $2 million in 2013 and less than $1 million in 2012.
Beginning in 2013, the Company replaced the defined benefit employer-sponsored retiree medical, prescription drug and dental coverage with a notional allocation to a Retiree Reimbursement Account. This change applies to both current and future Medicare eligible non-represented and future represented retirees, spouses, surviving spouses or same sex domestic partners when the youngest of the retiree's covered household turns age 65. The amount of the annual allocation to each participant is determined by the employee's retirement date: for employees who retired on or before January 1, 2013, the base allocation is $3,500, which increased to $3,570 in 2014 and for employees who retire after January 1, 2013, the base allocation is $3,250, which increased to $3,315 in 2014. The amount of the allocation will increase each year at the lower of the rate of medical inflation or 2%.
Net other postretirement cost includes the following components:
	2014			2013			2012
	(In millions)
Service cost	$	34		$	47		$	68
Interest cost	89			88			120
Expected return on plan assets	(122		)	(110		)	(92		)
Amortization of:
Net loss	20			64			80
Prior service credit	(144		)	(131		)	(25		)
Net other postretirement cost (credit)	$	(123	)	$	(42	)	$	151
	2014			2013
	(In millions)
Other changes in plan assets and APBO recognized in Regulatory assets (liabilities) and Other comprehensive income
Net actuarial (gain) loss	$	192		$	(353	)
Amortization of net actuarial loss	(20		)	(64		)
Prior service credit	—			(218		)
Amortization of prior service credit	144			131
Total recognized in Regulatory assets (liabilities) and Other comprehensive income	$	316		$	(504	)
Total recognized in net periodic benefit cost, Regulatory assets (liabilities) and Other comprehensive income	$	193		$	(546	)
Estimated amounts to be amortized from Regulatory assets (liabilities) and Accumulated other comprehensive income into net periodic benefit cost during next fiscal year
Net actuarial loss	$	43		$	21
Prior service credit	$	(126	)	$	(144	)
The following table reconciles the obligations, assets and funded status of the plans including amounts recorded as Accrued postretirement liability in the Consolidated Statements of Financial Position at December 31:
	2014			2013
	(In millions)
Change in accumulated postretirement benefit obligation
Accumulated postretirement benefit obligation, beginning of year	$	1,878		$	2,315
Service cost	34			47
Interest cost	89			88
Plan amendments	—			(218		)
Actuarial (gain) loss	131			(267		)
Medicare Part D subsidy	—			1
Benefits paid	(88		)	(88		)
Accumulated postretirement benefit obligation, end of year	$	2,044		$	1,878
Change in plan assets
Plan assets at fair value, beginning of year	$	1,527		$	1,153
Actual return on plan assets	62			196
Company contributions	24			264
Benefits paid	(85		)	(86		)
Plan assets at fair value, end of year	$	1,528		$	1,527
Funded status, end of year	$	(516	)	$	(351	)
Amount recorded as:
Current liabilities	$	(1	)	$	(1	)
Noncurrent liabilities	(515		)	(350		)
	$	(516	)	$	(351	)
Amounts recognized in Accumulated other comprehensive loss, pre-tax
Net actuarial loss	$	34		$	29
Prior service credit	(5		)	(10		)
	$	29		$	19
Amounts recognized in Regulatory assets (liabilities) (see Note 8)
Net actuarial loss	$	488		$	321
Prior service credit	(254		)	(393		)
	$	234		$	(72	)
At December 31, 2014, the benefits expected to be paid, including prescription drug benefits, in each of the next five years and in the aggregate for the five fiscal years thereafter are as follows:
	(In millions)
2015	$	101
2016	107
2017	111
2018	117
2019	122
2020-2024	660
Total	$	1,218
Assumptions used in determining the accumulated postretirement benefit obligation and net other postretirement benefit costs are listed below:
	2014		2013	2012
Accumulated postretirement benefit obligation
Discount rate	4.10%		4.95%	4.15%
Health care trend rate pre- and post- 65	7.50 / 6.50%		7.50 / 6.50%	7.00%
Ultimate health care trend rate	4.50%		4.50%	5.00%
Year in which ultimate reached pre- and post- 65	2025 / 2024		2025 / 2024	2021
Other postretirement benefit costs
Discount rate (prior to interim remeasurement)	4.95%		4.15%	5.00%
Discount rate (post interim remeasurement)	N/A		4.30%	N/A
Expected long-term rate of return on plan assets	8.00%		8.25%	8.25%
Health care trend rate pre- and post- 65	7.50 / 6.50%		7.00%	7.00%
Ultimate health care trend rate	4.50%		5.00%	5.00%
Year in which ultimate reached pre- and post- 65	2025 / 2024		2021	2020
A one percentage point increase in health care cost trend rates would have increased the total service cost and interest cost components of benefit costs by $8 million in 2014 and increased the accumulated benefit obligation by $108 million at December 31, 2014. A one percentage point decrease in the health care cost trend rates would have decreased the total service and interest cost components of benefit costs by $7 million in 2014 and would have decreased the accumulated benefit obligation by $94 million at December 31, 2014.
The process used in determining the long-term rate of return for assets and the investment approach for the Company’s other postretirement benefits plans is similar to those previously described for its pension plans.
Target allocations for other postretirement benefit plan assets as of December 31, 2014 are listed below:
U.S. Large Cap Equity Securities	17	%
U.S. Small Cap and Mid Cap Equity Securities	4
Non U.S. Equity Securities	20
Fixed Income Securities	25
Hedge Funds and Similar Investments	20
Private Equity and Other	14
	100	%
Fair Value Measurements for other postretirement benefit plan assets at December 31, 2014 and 2013 (a):
	December 31, 2014												31-Dec-13
	Level 1			Level 2			Level 3			Total			Level 1			Level 2			Level 3		Total
Asset category:	(In millions)
Short-term investments (b)	$	6		$	—		$	—		$	6		$	5		$	—		$	—	$	5
Equity securities
U.S. large cap (c)	266			—			—			266			302			—			—		302
U.S. small/mid cap (d)	149			—			—			149			147			—			—		147
Non U.S. (e)	222			59			—			281			282			9			—		291
Fixed income securities (f)	15			360			—			375			17			350			—		367
Hedge funds and similar investments (g)	107			45			168			320			130			25			159		314
Private equity and other (h)	—			—			131			131			—			—			101		101
Securities lending (i)	(141		)	(17		)	—			(158		)	—			—			—		—
Securities lending collateral (i)	141			17			—			158			—			—			—		—
Total	$	765		$	464		$	299		$	1,528		$	883		$	384		$	260	$	1,527
_______________________________________
(a)	For a description of levels within the fair value hierarchy see Note 11 to the Consolidated Financial Statements, "Fair Value".
(b)	This category predominantly represents certain short-term fixed income securities and money market investments that are managed in separate accounts or commingled funds. Pricing for investments in this category are obtained from quoted prices in actively traded markets or valuations from brokers or pricing services.
(c)	This category comprises both actively and not actively managed portfolios that track the S&P 500 low cost equity index funds. Investments in this category are exchange-traded securities whereby unadjusted quote prices can be obtained. Exchange-traded securities held in a commingled fund are classified as Level 2 assets.
(d)	This category represents portfolios of small and medium capitalization domestic equities. Investments in this category are exchange-traded securities whereby unadjusted quote prices can be obtained. Exchange-traded securities held in a commingled fund are classified as Level 2 assets.
(e)	This category primarily consists of portfolios of non-U.S. developed and emerging market equities. Investments in this category are exchange-traded securities whereby unadjusted quote prices can be obtained. Exchange-traded securities held in a commingled fund are classified as Level 2 assets.
(f)	This category includes corporate bonds from diversified industries, U.S. Treasuries, bank loans and mortgage backed securities. Pricing for investments in this category is obtained from quoted prices in actively traded markets and quotations from broker or pricing services. Non-exchange traded securities and exchange-traded securities held in commingled funds are classified as Level 2 assets.
(g)	This category utilizes a diversified group of strategies that attempt to capture financial market inefficiencies and includes publicly traded debt and equity, publicly traded mutual funds, commingled and limited partnership funds and non-exchange traded securities. Pricing for Level 1 and Level 2 assets in this category is obtained from quoted prices in actively traded markets and quoted prices from broker or pricing services. Non-exchange traded securities held in commingled funds are classified as Level 2 assets. Valuations for some Level 3 assets in this category may be based on limited observable inputs as there may be little, if any, publicly available pricing.
(h)	This category includes a diversified group of funds and strategies that primarily invests in private equity partnerships. This category also includes investments in timber and private mezzanine debt. Pricing for investments in this category is based on limited observable inputs as there is little, if any, publicly available pricing. Valuations for assets in this category may be based on discounted cash flow analyses, relevant publicly-traded comparables and comparable transactions.
(i)	In 2014, DTE Energy began a securities lending program with a third party agent. The program allows the agent to lend certain securities from the Company's VEBA trust to selected entities against receipt of collateral (in the form of cash) as provided for and determined in accordance with its securities lending agency agreement.
The VEBA trust holds debt and equity securities directly and indirectly through commingled funds and institutional mutual funds. Exchange-traded debt and equity securities held directly are valued using quoted market prices in actively traded markets. The commingled funds and institutional mutual funds hold exchange-traded equity or debt securities and are valued based on NAVs. Non-exchange traded fixed income securities are valued by the trustee based upon quotations available from brokers or pricing services. A primary price source is identified by asset type, class or issue for each security. The trustee monitors prices supplied by pricing services and may use a supplemental price source or change the primary price source of a given security if the trustee challenges an assigned price and determines that another price source is considered to be preferable. DTE Energy has obtained an understanding of how these prices are derived, including the nature and observability of the inputs used in deriving such prices. Additionally, DTE Energy selectively corroborates the fair values of securities by comparison of market-based price sources.
Fair Value Measurements Using Significant Unobservable Inputs (Level 3):
	Year Ended December 31, 2014									Year Ended December 31, 2013
	Hedge Funds			Private Equity			Total			Hedge Funds			Private Equity			Total
	and Similar			and Other						and Similar			and Other
	Investments									Investments
	(In millions)
Beginning Balance at January 1	$	159		$	101		$	260		$	119		$	86		$	205
Total realized/unrealized gains (losses)	8			9			17			14			9			23
Purchases, sales and settlements:
Purchases	9			33			42			26			15			41
Sales	(8		)	(12		)	(20		)	—			(9		)	(9		)
Ending Balance at December 31	$	168		$	131		$	299		$	159		$	101		$	260
The amount of total gains for the period attributable to the change in unrealized gains or losses related to assets still held at the end of the period	$	7		$	8		$	15		$	14		$	9		$	23
There were no transfers between Level 3 and Level 2 and there were no significant transfers between Level 2 and Level 1 in the years ended December 31, 2014 and 2013.
Interim Re-Measurement of Other Postretirement Benefit Obligation
In March 2013, the Company reached agreements on new four-year labor contracts with certain represented employees under several bargaining units. As a term of the agreements, the Company replaced the defined benefit employer-sponsored retiree medical, prescription drug and dental coverage for future Medicare eligible retirees and their covered dependents with an allocation to a Retiree Reimbursement Account, when the youngest of the retiree's covered household turns age 65. The amount of the allocation is $3,250 per year for each eligible participant, which increased to $3,315 in 2014. The amount of the allocation will increase each year at the lower of the rate of medical inflation or 2%. The modification in retiree health coverage will reduce future other postretirement benefit costs.
Based on the impact of such benefit cost savings on the Consolidated Financial Statements, the Company re-measured its retiree health plan as of March 31, 2013. In performing the re-measurement, the Company updated its significant actuarial assumptions, including an adjustment to the discount rate from 4.15% at December 31, 2012 to 4.30% at March 31, 2013. Plan assets were also updated to reflect fair value as of the re-measurement date. Beginning April 2013, net other postretirement benefit costs were recorded based on the updated actuarial assumptions and benefit changes resulting from the new labor contracts.
Grantor Trust
DTE Gas maintains a Grantor Trust that invests in life insurance contracts and income securities to fund other postretirement benefit obligations. Employees and retirees have no right, title or interest in the assets of the Grantor Trust, and DTE Gas can revoke the trust subject to providing the MPSC with prior notification. The Company accounts for its investment at fair value, which approximated $18 million and $17 million at December 31, 2014 and 2013, respectively, with unrealized gains and losses recorded to earnings. The Grantor Trust investment is included in Other investments on the Consolidated Statements of Financial Position.
Defined Contribution Plans
The Company also sponsors defined contribution retirement savings plans. Participation in one of these plans is available to substantially all represented and non-represented employees. The Company matches employee contributions up to certain predefined limits based upon eligible compensation, the employee’s contribution rate and, in some cases, years of credited service. The cost of these plans was $48 million, $41 million and $37 million in each of the years 2014, 2013 and 2012, respectively.

StockBased_Compensation_Notes

Stock-Based Compensation (Notes)	12 Months Ended
	Dec. 31, 2014
Share-based Compensation [Abstract]
Stock-based Compensation	STOCK-BASED COMPENSATION
	The Company’s stock incentive program permits the grant of incentive stock options, non-qualifying stock options, stock awards, performance shares and performance units to employees and members of its Board of Directors. As a result of a stock award, a settlement of an award of performance shares, or by exercise of a participant’s stock option, the Company may deliver common stock from the Company’s authorized but unissued common stock and/or from outstanding common stock acquired by or on behalf of the Company in the name of the participant. Key provisions of the stock incentive program are:
	•	Authorized limit is 14,500,000 shares of common stock;
	•	Prohibits the grant of a stock option with an exercise price that is less than the fair market value of the Company’s stock on the date of the grant; and
	•	Imposes the following award limits to a single participant in a single calendar year, (1) options for more than 500,000 shares of common stock; (2) stock awards for more than 150,000 shares of common stock; (3) performance share awards for more than 300,000 shares of common stock (based on the maximum payout under the award); or (4) more than 1,000,000 performance units, which have a face amount of $1.00 each.
	The Company records compensation expense at fair value over the vesting period for all awards it grants.
	The following table summarizes the components of stock-based compensation:
		2014			2013			2012
		(In millions)
	Stock-based compensation expense	$	103		$	99		$	83
	Tax benefit	40			38			33
	Stock-based compensation cost capitalized in property, plant and equipment	16			15			5
	Stock Options
	Options are exercisable according to the terms of the individual stock option award agreements and expire 10 years after the date of the grant. The option exercise price equals the fair value of the stock on the date that the option was granted. Stock options vest ratably over a 3-year period.
	The following table summarizes our stock option activity for the year ended December 31, 2014:
		Number of Options		Weighted Average Exercise Price			Aggregate Intrinsic
							Value
							(In millions)
	Options outstanding at December 31, 2013	723,697		$	42.6
	Granted	—		$	—
	Exercised	(268,689	)	$	41.14
	Forfeited or expired	(10,730	)	$	39.41
	Options outstanding and exercisable at December 31, 2014	444,278		$	43.56		$	17
	As of December 31, 2014, the weighted average remaining contractual life for the exercisable shares is 3.41 years. As of December 31, 2014, all options were vested. No options vested during 2014.
	There were no options granted during 2014, 2013 or 2012. The intrinsic value of options exercised for the years ended December 31, 2014, 2013 and 2012 was $11 million, $12 million and $25 million, respectively. Total option expense recognized was zero for 2014 and 2013 and $0.7 million for 2012.
	The number, weighted average exercise price and weighted average remaining contractual life of options outstanding were as follows:
	Range of Exercise Prices						Number of Options			Weighted Average		Weighted Average
										Exercise Price		Remaining Contractual Life (Years)
	$	27	—	$	38		25,857			$	27.7	4.16
	$	38.01	—	$	42		82,834			$	41.77	3.16
	$	42.01	—	$	45		221,487			$	43.93	4.06
	$	45.01	—	$	50		114,100			$	47.75	2.15
							444,278			$	43.56	3.41
	Restricted Stock Awards
	Stock awards granted under the plan are restricted for varying periods, generally for three years. Participants have all rights of a shareholder with respect to a stock award, including the right to receive dividends and vote the shares. Prior to vesting in stock awards, the participant: (i) may not sell, transfer, pledge, exchange or otherwise dispose of shares; (ii) shall not retain custody of the share certificates; and (iii) will deliver to the Company a stock power with respect to each stock award upon request.
	The stock awards are recorded at cost that approximates fair value on the date of grant. The cost is amortized to compensation expense over the vesting period.
	Stock award activity for the years ended December 31 was:
		2014			2013			2012
	Fair value of awards vested (in millions)	$	11		$	8		$	9
	Restricted common shares awarded	159,590			127,785			167,320
	Weighted average market price of shares awarded	$	70.09		$	64.72		$	53.71
	Compensation cost charged against income (in millions)	$	10		$	23		$	12
	The following table summarizes the Company’s restricted stock awards activity for the year ended December 31, 2014:
		Restricted		Weighted Average
		Stock		Grant Date
				Fair Value
	Balance at December 31, 2013	492,329		$	53.76
	Grants	159,590		$	70.09
	Forfeitures	(16,841	)	$	62.41
	Vested and issued	(218,760	)	$	47.77
	Balance at December 31, 2014	416,318		$	62.82
	Performance Share Awards
	Performance shares awarded under the plan are for a specified number of shares of common stock that entitle the holder to receive a cash payment, shares of common stock or a combination thereof. The final value of the award is determined by the achievement of certain performance objectives and market conditions. The awards vest at the end of a specified period, usually three years. Awards granted in 2014 were primarily deemed to be equity awards. The stock price and number of probable shares attributable to market conditions for such equity awards are fair valued only at the grant date. Performance shares awarded prior to 2014 are liability awards and are remeasured to fair value at each reporting period. The Company accounts for performance share awards by accruing compensation expense over the vesting period based on: (i) the number of shares expected to be paid which is based on the probable achievement of performance objectives; and (ii) the closing stock price market value. The settlement of the award is based on the closing price at the settlement date.
	The Company recorded compensation expense for performance share awards as follows:
		2014			2013			2012
		(In millions)
	Compensation expense	$	93		$	77		$	71
	Cash settlements (a)	$	11		$	9		$	4
	Stock settlements (a)	$	61		$	56		$	41
	_______________________________________
	(a)	Sum of cash and stock settlements approximates the intrinsic value of the liability.
	During the vesting period, the recipient of a performance share award has no shareholder rights. During the period beginning on the date the performance shares are awarded and ending on the certification date of the performance objectives, the number of performance shares awarded will be increased, assuming full dividend reinvestment at the fair market value on the dividend payment date. The cumulative number of performance shares will be adjusted to determine the final payment based on the performance objectives achieved. Performance share awards are nontransferable and are subject to risk of forfeiture.
	The following table summarizes the Company’s performance share activity for the period ended December 31, 2014:
		Performance Shares		Weighted Average
Grant Date
Fair Value
Balance at December 31, 2013	1,608,789		$	—
Grants	561,335		$	69.32
Forfeitures	(44,250	)	$	69.16
Payouts	(571,177	)	$	—
Balance at December 31, 2014	1,554,697		$	69.32
Unrecognized Compensation Costs
As of December 31, 2014, the total unrecognized compensation cost related to non-vested stock incentive plan arrangements and the weighted average recognition period was as follows:
	Unrecognized			Weighted Average
	Compensation			to be Recognized
	Cost
	(In millions)			(In years)
Stock awards	$	10		1.06
Performance shares	48			0.98
	$	58		0.99

Segment_and_Related_Informatio

Segment and Related Information (Notes)	12 Months Ended
	Dec. 31, 2014
Segment Reporting [Abstract]
Segment and Related Information	SEGMENT AND RELATED INFORMATION
	The Company sets strategic goals, allocates resources and evaluates performance based on the following structure:
	Electric segment consists principally of DTE Electric, which is engaged in the generation, purchase, distribution and sale of electricity to approximately 2.1 million residential, commercial and industrial customers in southeastern Michigan.
	Gas segment consists principally of DTE Gas, which is engaged in the purchase, storage, transportation, distribution and sale of natural gas to approximately 1.2 million residential, commercial and industrial customers throughout Michigan and the sale of storage and transportation capacity.
	Gas Storage and Pipelines consists of natural gas pipeline, gathering and storage businesses.
	Power and Industrial Projects is comprised primarily of projects that deliver energy and utility-type products and services to industrial, commercial and institutional customers; produce REF and sell electricity from renewable energy projects.
	Energy Trading consists of energy marketing and trading operations.
	Corporate and Other, includes various holding company activities, holds certain non-utility debt and energy-related investments.
	The federal income tax provisions or benefits of DTE Energy’s subsidiaries are determined on an individual company basis and recognize the tax benefit of production tax credits and net operating losses if applicable. The state and local income tax provisions of the utility subsidiaries are determined on an individual company basis and recognize the tax benefit of various tax credits and net operating losses, if applicable. The subsidiaries record federal, state and local income taxes payable to or receivable from DTE Energy based on the federal, state and local tax provisions of each company.
	Inter-segment billing for goods and services exchanged between segments is based upon tariffed or market-based prices of the provider and primarily consists of the sale of reduced emissions fuel, power sales and natural gas sales in the following segments:
		2014			2013			2012
		(In millions)
	Electric	$	29		$	26		$	29
	Gas	6			4			4
	Power and Industrial Projects	794			816			801
	Gas Storage and Pipelines	9			3			6
	Energy Trading	33			43			43
	Corporate and Other	3			(24		)	(37		)
	Discontinued Operations	—			—			2
		$	874		$	868		$	848
	Financial data of the business segments follows:
		Operating			Depreciation,			Interest			Interest			Income			Net Income (Loss)			Total			Goodwill		Capital
		Revenue			Depletion &			Income			Expense			Tax Expense (Benefit)			Attributable			Assets					Expenditures and Acquisitions
					Amortization												to DTE
																	Energy
																	Company
		(In millions)
	2014
	Electric	$	5,283		$	933		$	(1	)	$	250		$	296		$	528		$	18,715		$	1,208	$	1,561
	Gas	1,636			99			(7		)	57			78			140			4,283			743		224
	Power and Industrial Projects	2,289			77			(5		)	28			(100		)	90			1,009			26		77
	Gas Storage and Pipelines	203			34			(6		)	22			53			82			884			24		184
	Energy Trading	3,762			1			—			7			77			122			755			17		3
	Corporate and Other	2			1			(48		)	122			(40		)	(57		)	3,209			—		—
	Reclassifications and Eliminations	(874		)	—			57			(57		)	—			—			(881		)	—		—
	Total	$	12,301		$	1,145		$	(10	)	$	429		$	364		$	905		$	27,974		$	2,018	$	2,049
		Operating			Depreciation,			Interest			Interest			Income			Net Income (Loss)			Total			Goodwill		Capital
		Revenue			Depletion &			Income			Expense			Tax Expense (Benefit)			Attributable			Assets					Expenditures and Acquisitions
					Amortization												to DTE
																	Energy
																	Company
		(In millions)
	2013
	Electric	$	5,199		$	902		$	(1	)	$	268		$	252		$	484		$	17,508		$	1,208	$	1,325
	Gas	1,474			95			(7		)	58			77			143			3,938			743		209
	Power and Industrial Projects	1,950			72			(6		)	27			(45		)	66			1,067			26		93
	Gas Storage and Pipelines	132			23			(7		)	18			45			70			824			24		245
	Energy Trading	1,771			1			—			8			(38		)	(58		)	623			17		3
	Corporate and Other	3			1			(51		)	120			(37		)	(44		)	2,945			—		1
	Reclassifications and Eliminations	(868		)	—			63			(63		)	—			—			(970		)	—		—
	Total	$	9,661		$	1,094		$	(9	)	$	436		$	254		$	661		$	25,935		$	2,018	$	1,876
		Operating			Depreciation,			Interest			Interest			Income			Net Income (Loss)			Total			Goodwill		Capital
		Revenue			Depletion &			Income			Expense			Tax Expense (Benefit)			Attributable			Assets					Expenditures and Acquisitions
					Amortization												to DTE
																	Energy
																	Company
		(In millions)
	2012
	Electric	$	5,293		$	827		$	(1	)	$	272		$	280		$	483		$	17,755		$	1,208	$	1,230
	Gas	1,315			92			(7		)	59			50			115			4,059			745		221
	Power and Industrial Projects	1,823			65			(7		)	37			(44		)	42			991			26		281
	Gas Storage and Pipelines	96			8			(8		)	8			39			61			668			22		233
	Energy Trading	1,109			2			—			8			7			12			629			17		1
	Corporate and Other	3			1			(52		)	121			(46		)	(47		)	3,074			—		3
Reclassifications and Eliminations	(848		)	—			65			(65		)	—			—			(837		)	—		—
Total from Continuing Operations	$	8,791		$	995		$	(10	)	$	440		$	286		$	666		$	26,339		$	2,018	$	1,969
Discontinued Operations (Note 4)																(56		)	—			—		49
Total																$	610		$	26,339		$	2,018	$	2,018

Supplementary_Quarterly_Financ

Supplementary Quarterly Financial Information (Unaudited)	12 Months Ended
	Dec. 31, 2014
Quarterly Financial Information Disclosure [Abstract]
Supplemental Quarterly Financial Information (Unaudited)	SUPPLEMENTARY QUARTERLY FINANCIAL INFORMATION (UNAUDITED)
	Quarterly earnings per share may not equal full year totals, since quarterly computations are based on weighted average common shares outstanding during each quarter.
		First		Second		Third		Fourth		Year
		Quarter		Quarter		Quarter		Quarter
		(In millions, except per share amounts)
	2014
	Operating Revenues	$	3,930	$	2,698	$	2,595	$	3,078	$	12,301
	Operating Income	$	560	$	249	$	239	$	542	$	1,590
	Net Income Attributable to DTE Energy Company	$	326	$	124	$	156	$	299	$	905
	Basic Earnings per Share	$	1.84	$	0.7	$	0.88	$	1.68	$	5.11
	Diluted Earnings per Share	$	1.84	$	0.7	$	0.88	$	1.68	$	5.1
	2013
	Operating Revenues	$	2,516	$	2,225	$	2,387	$	2,533	$	9,661
	Operating Income	$	410	$	223	$	329	$	241	$	1,203
	Net Income Attributable to DTE Energy Company	$	234	$	105	$	198	$	124	$	661
	Basic Earnings per Share	$	1.35	$	0.6	$	1.13	$	0.7	$	3.76
	Diluted Earnings per Share	$	1.34	$	0.6	$	1.13	$	0.7	$	3.76

Subsequent_Event_Notes

Subsequent Event (Notes)	12 Months Ended
	Dec. 31, 2014
Subsequent Events [Abstract]
Subsequent Event	SUBSEQUENT EVENT
	In October 2014, DTE Electric executed an agreement to purchase a 732 MW simple-cycle natural gas facility in Carson City, Michigan from The LS Power Group for a total purchase price of approximately $240 million paid in cash. This facility will serve to meet the needs of approximately 260,000 additional households during peak demand. DTE Electric closed on the acquisition on January 21, 2015.
	Effective upon closing, DTE Electric obtained control over and applied acquisition accounting to the acquired business. Due to the limited time since the acquisition date, the initial accounting for the business combination is incomplete. As a result, DTE Electric is unable to provide amounts recognized as of the acquisition date for major classes of assets and liabilities acquired. DTE Electric will include required information in the Quarterly Report on Form 10-Q for the period ending March 31, 2015.

Valuation_and_Qualifying_Accou

Valuation and Qualifying Accounts (Notes)	12 Months Ended
	Dec. 31, 2014
Valuation and Qualifying Accounts [Abstract]
Schedule II Valuation and Qualifying Accounts	Valuation and Qualifying Accounts
		Year Ending December 31,
		2014			2013			2012
		(In millions)
	Allowance for Doubtful Accounts (shown as deduction from Accounts Receivable in the Consolidated Statements of Financial Position)
	Balance at Beginning of Period	$	55		$	62		$	162
	Additions:
	Charged to costs and expenses	95			94			79
	Charged to other accounts (a)	20			23			16
	Deductions (b)	(116		)	(124		)	(195		)
	Balance at End of Period	$	54		$	55		$	62
	_______________________________________
	(a)	Collection of accounts previously written off.
	(b)	Uncollectible accounts written off.

Significant_Accounting_Policie1

Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2014
Accounting Policies [Abstract]
Basis of Presentation	Basis of Presentation
	The accompanying Consolidated Financial Statements are prepared using accounting principles generally accepted in the United States of America. These accounting principles require management to use estimates and assumptions that impact reported amounts of assets, liabilities, revenues and expenses, and the disclosure of contingent assets and liabilities. Actual results may differ from the Company’s estimates.
Principles of Consolidation	Principles of Consolidation
	The Company consolidates all majority-owned subsidiaries and investments in entities in which it has controlling influence. Non-majority owned investments are accounted for using the equity method when the Company is able to influence the operating policies of the investee. When the Company does not influence the operating policies of an investee, the cost method is used. These Consolidated Financial Statements also reflect the Company's proportionate interests in certain jointly owned utility plants. The Company eliminates all intercompany balances and transactions.
	The Company evaluates whether an entity is a VIE whenever reconsideration events occur. The Company consolidates VIEs for which it is the primary beneficiary. If the Company is not the primary beneficiary and an ownership interest is held, the VIE is accounted for under the equity method of accounting. When assessing the determination of the primary beneficiary, the Company considers all relevant facts and circumstances, including: the power, through voting or similar rights, to direct the activities of the VIE that most significantly impact the VIE's economic performance and the obligation to absorb the expected losses and/or the right to receive the expected returns of the VIE. The Company performs ongoing reassessments of all VIEs to determine if the primary beneficiary status has changed.
	Legal entities within the Company's Power and Industrial Projects segment enter into long-term contractual arrangements with customers to supply energy-related products or services. The entities are generally designed to pass-through the commodity risk associated with these contracts to the customers, with the Company retaining operational and customer default risk. These entities generally are VIEs and consolidated when the Company is the primary beneficiary. In addition, we have interests in certain VIEs through which we share control of all significant activities for those entities with our partners, and therefore are accounted for under the equity method.
	The Company has variable interests in VIEs through certain of its long-term purchase and sale contracts. As of December 31, 2014, the carrying amount of assets and liabilities in the Consolidated Statements of Financial Position that relate to its variable interests under long-term purchase and sale contracts are predominately related to working capital accounts and generally represent the amounts owed by or to the Company for the deliveries associated with the current billing cycle under the contracts. The Company has not provided any significant form of financial support associated with these long-term contracts. There is no significant potential exposure to loss as a result of its variable interests through these long-term purchase and sale contracts.
	In 2001, DTE Electric financed a regulatory asset related to Fermi 2 and certain other regulatory assets through the sale of rate reduction bonds by a wholly-owned special purpose entity, Securitization. DTE Electric performs servicing activities including billing and collecting surcharge revenue for Securitization. This entity is a VIE and is consolidated by the Company.
	The maximum risk exposure for consolidated VIEs is reflected on the Company's Consolidated Statements of Financial Position. For non-consolidated VIEs, the maximum risk exposure is generally limited to its investment and amounts which it has guaranteed.
	The following table summarizes the major balance sheet items for consolidated VIEs as of December 31, 2014 and 2013. All assets and liabilities of a consolidated VIE are presented where it has been determined that a consolidated VIE has either (1) assets that can be used only to settle obligations of the VIE or (2) liabilities for which creditors do not have recourse to the general credit of the primary beneficiary. VIEs, in which the Company holds a majority voting interest and is the primary beneficiary, that meet the definition of a business and whose assets can be used for purposes other than the settlement of the VIE's obligations have been excluded from the table below.
Revenues	Revenues
	Revenues from the sale and delivery of electricity, and the sale, delivery and storage of natural gas are recognized as services are provided. DTE Electric and DTE Gas record revenues for electricity and gas provided but unbilled at the end of each month. Rates for DTE Electric and DTE Gas include provisions to adjust billings for fluctuations in fuel and purchased power costs, cost of natural gas and certain other costs. Revenues are adjusted for differences between actual costs subject to reconciliation and the amounts billed in current rates. Under or over recovered revenues related to these cost recovery mechanisms are recorded on the Consolidated Statements of Financial Position and are recovered or returned to customers through adjustments to the billing factors.
	For further discussion of recovery mechanisms authorized by the MPSC see Note 8 to the Consolidated Financial Statements, "Regulatory Matters".
	Non-utility businesses recognize revenues as services are provided and products are delivered. For discussion of derivative contracts see Note 12 to the Consolidated Financial Statements, "Financial and Other Derivative Instruments".
Accounting For ISO Transactions	Accounting for ISO Transactions
	DTE Electric participates in the energy market through MISO. MISO requires that we submit hourly day-ahead, real- time and FTR bids and offers for energy at locations across the MISO region. DTE Electric accounts for MISO transactions on a net hourly basis in each of the day-ahead, real-time and FTR markets and net transactions across all MISO energy market locations. In any single hour DTE Electric records net purchases in Fuel, purchased power and gas and net sales in Operating revenues on the Consolidated Statements of Operations.
	Energy Trading participates in the energy markets through various independent system operators and regional transmission organizations (ISOs and RTOs). These markets require that Energy Trading submits hourly day-ahead, real-time bids and offers for energy at locations across each region. Energy Trading submits bids in the annual and monthly auction revenue rights and FTR auctions to the regional transmission organizations. Energy Trading accounts for these transactions on a net hourly basis for the day-ahead, real-time and FTR markets. These transactions are related to trading contracts which are presented on a net basis in Operating Revenues in the Consolidated Statements of Operations.
	DTE Electric and Energy Trading record accruals for future net purchases adjustments based on historical experience, and reconcile accruals to actual costs when invoices are received from MISO, and other ISOs and RTOs.
Changes in Accumulated Other Comprehensive Loss	Changes in Accumulated Other Comprehensive Loss
	Comprehensive income (loss) is the change in common shareholders’ equity during a period from transactions and events from non-owner sources, including net income. The amounts recorded to accumulated other comprehensive loss include unrealized gains and losses from derivatives accounted for as cash flow hedges, unrealized gains and losses on available-for-sale securities and the Company’s interest in other comprehensive income of equity investees, which comprise the net unrealized gains and losses on investments, changes in benefit obligations, consisting of deferred actuarial losses, prior service costs, and foreign currency translation adjustments.
Cash, Cash Equivalents and Restricted Cash	Cash, Cash Equivalents and Restricted Cash
	Cash and cash equivalents include cash on hand, cash in banks and temporary investments purchased with remaining maturities of three months or less. Restricted cash consists of funds held to satisfy requirements of certain debt, primarily Securitization bonds, and partnership operating agreements. Restricted cash designated for interest and principal payments within one year is classified as a current asset.
Receivables	Receivables
	Accounts receivable are primarily composed of trade receivables and unbilled revenue. Our accounts receivable are stated at net realizable value.
	The allowance for doubtful accounts for DTE Electric and DTE Gas is generally calculated using the aging approach that utilizes rates developed in reserve studies. We establish an allowance for uncollectible accounts based on historical losses and management’s assessment of existing economic conditions, customer trends, and other factors. Customer accounts are generally considered delinquent if the amount billed is not received by the due date, which is typically in 21 days, however, factors such as assistance programs may delay aggressive action. We assess late payment fees on trade receivables based on past-due terms with customers. Customer accounts are written off when collection efforts have been exhausted. The time period for write-off is 150 days after service has been terminated.
	The customer allowance for doubtful accounts for our other businesses is calculated based on specific review of probable future collections based on receivable balances in excess of 30 days.
	Unbilled revenues of $773 million and $815 million are included in customer accounts receivable at December 31, 2014 and 2013, respectively.
	Notes Receivable
	Notes receivable, or financing receivables, are primarily comprised of capital lease receivables and loans and are included in Notes receivable and Other current assets on the Company’s Consolidated Statements of Financial Position.
	Notes receivable are typically considered delinquent when payment is not received for periods ranging from 60 to 120 days. The Company ceases accruing interest (nonaccrual status), considers a note receivable impaired, and establishes an allowance for credit loss when it is probable that all principal and interest amounts due will not be collected in accordance with the contractual terms of the note receivable. Cash payments received on nonaccrual status notes receivable, that do not bring the account contractually current, are first applied to contractually owed past due interest, with any remainder applied to principal. Accrual of interest is generally resumed when the note receivable becomes contractually current.
	In determining the allowance for credit losses for notes receivable, we consider the historical payment experience and other factors that are expected to have a specific impact on the counterparty’s ability to pay. In addition, the Company monitors the credit ratings of the counterparties from which we have notes receivable.
Inventories	Inventories
	The Company generally values inventory at average cost.
	Natural gas inventory of $43 million and $4 million as of December 31, 2014 and 2013, respectively, at DTE Gas is determined using the last-in, first-out (LIFO) method. At December 31, 2014, the replacement cost of gas remaining in storage exceeded the LIFO cost by $110 million. At December 31, 2013, the replacement cost of gas remaining in storage exceeded the LIFO cost by $170 million.
Property, Retirement and Maintenance, Depreciation, Depletion and Amortization	Property, Retirement and Maintenance, and Depreciation, Depletion and Amortization
	Property is stated at cost and includes construction-related labor, materials, overheads and AFUDC for utility property. The cost of utility properties retired is charged to accumulated depreciation. Expenditures for maintenance and repairs are charged to expense when incurred, except for Fermi 2.
	Utility property at DTE Electric and DTE Gas is depreciated over its estimated useful life using straight-line rates approved by the MPSC.
	Non-utility property is depreciated over its estimated useful life using the straight-line and units of production methods.
	Depreciation, depletion and amortization expense also includes the amortization of certain regulatory assets.
	Approximately $16 million and $26 million of expenses related to Fermi 2 refueling outages were accrued at December 31, 2014 and 2013, respectively. Amounts are accrued on a pro-rata basis, generally over an 18-month period, that coincides with scheduled refueling outages at Fermi 2. This accrual of outage costs matches the regulatory recovery of these costs in rates set by the MPSC. See Note 8 to the Consolidated Financial Statements, "Regulatory Matters".
	The cost of nuclear fuel is capitalized. The amortization of nuclear fuel is included within Fuel, purchased power, and gas in the Consolidated Statements of Operations and is recorded using the units-of-production method.
	Capitalized software costs are classified as Property, plant and equipment and the related amortization is included in Accumulated depreciation, depletion and amortization on the Consolidated Statements of Financial Position. The Company capitalizes the costs associated with computer software it develops or obtains for use in its business. The Company amortizes capitalized software costs on a straight-line basis over the expected period of benefit, ranging from 3 to 15 years.
Long-Lived Assets	Long-Lived Assets
	Long-lived assets are reviewed for impairment whenever events or changes in circumstances indicate the carrying amount of an asset may not be recoverable. If the carrying amount of the asset exceeds the expected discounted future cash flows generated by the asset, an impairment loss is recognized resulting in the asset being written down to its estimated fair value. Assets to be disposed of are reported at the lower of the carrying amount or fair value, less costs to sell.
Intangible Assets	Emission allowances and renewable energy credits are charged to expense, using average cost, as the allowances and credits are consumed in the operation of the business. The Company amortizes contract intangible assets on a straight-line basis over the expected period of benefit, ranging from 1 to 27 years.
Deferred Debt Costs	Deferred Debt Costs
	The costs related to the issuance of long-term debt are deferred and amortized over the life of each debt issue. In accordance with MPSC regulations applicable to the Company’s electric and gas utilities, the unamortized discount, premium and expense related to utility debt redeemed with a refinancing are amortized over the life of the replacement issue. Discount, premium and expense on early redemptions of debt associated with non-utility operations are charged to earnings.
Investments in Debt and Equity Securities	Investments in Debt and Equity Securities
	The Company generally classifies investments in debt and equity securities as either trading or available-for-sale and has recorded such investments at market value with unrealized gains or losses included in earnings or in other comprehensive income or loss, respectively. Changes in the fair value of Fermi 2 nuclear decommissioning investments are recorded as adjustments to regulatory assets or liabilities, due to a recovery mechanism from customers. The Company’s equity investments are reviewed for impairment each reporting period. If the assessment indicates that the impairment is other than temporary, a loss is recognized resulting in the equity investment being written down to its estimated fair value. See Note 11 of the Consolidated Financial Statements, "Fair Value".
Government Grants	Government Grants
	Grants are recognized when there is reasonable assurance that the grant will be received and that any conditions associated with the grant will be met. When grants are received related to Property, plant and equipment, the Company reduces the cost of the assets on the Consolidated Statements of Financial Position, resulting in lower depreciation expense over the life of the associated asset. Grants received related to expenses are reflected as a reduction of the associated expense in the period in which the expense is incurred.
Foundation Related Party	The DTE Energy Foundation is a non-consolidated not-for-profit private foundation, the purpose of which is to contribute to and assist charitable organizations
Asset Retirement Obligations	The Company has a legal retirement obligation for the decommissioning costs for its Fermi 1 and Fermi 2 nuclear plants, dismantlement of facilities located on leased property and various other operations. The Company has conditional retirement obligations for gas pipelines, asbestos and PCB removal at certain of its power plants and various distribution equipment. The Company recognizes such obligations as liabilities at fair market value when they are incurred, which generally is at the time the associated assets are placed in service. Fair value is measured using expected future cash outflows discounted at our credit-adjusted risk-free rate. In its regulated operations, the Company recognizes regulatory assets or liabilities for timing differences in expense recognition for legal asset retirement costs that are currently recovered in rates.
	If a reasonable estimate of fair value cannot be made in the period in which the retirement obligation is incurred, such as for assets with indeterminate lives, the liability is recognized when a reasonable estimate of fair value can be made. Natural gas storage system assets, substations, manholes and certain other distribution assets have an indeterminate life. Therefore, no liability has been recorded for these assets.
Regulatory Matters	DTE Electric and DTE Gas are required to record regulatory assets and liabilities for certain transactions that would have been treated as revenue or expense in non-regulated businesses. Continued applicability of regulatory accounting treatment requires that rates be designed to recover specific costs of providing regulated services and be charged to and collected from customers. Future regulatory changes or changes in the competitive environment could result in the discontinuance of this accounting treatment for regulatory assets and liabilities for some or all of our businesses and may require the write-off of the portion of any regulatory asset or liability that was no longer probable of recovery through regulated rates. Management believes that currently available facts support the continued use of regulatory assets and liabilities and that all regulatory assets and liabilities are recoverable or refundable in the current regulatory environment.
Income Taxes	Excise and Sales Taxes
	The Company records the billing of excise and sales taxes as a receivable with an offsetting payable to the applicable taxing authority, with no net impact on the Consolidated Statements of Operations.
	Deferred tax assets and liabilities are recognized for the estimated future tax effect of temporary differences between the tax basis of assets or liabilities and the reported amounts in the financial statements. Deferred tax assets and liabilities are classified as current or noncurrent according to the classification of the related assets or liabilities. Deferred tax assets and liabilities not related to assets or liabilities are classified according to the expected reversal date of the temporary differences. Consistent with rate making treatment, deferred taxes are offset in the table below for temporary differences which have related regulatory assets and liabilities.
	The federal income tax provisions or benefits of DTE Energy’s subsidiaries are determined on an individual company basis and recognize the tax benefit of production tax credits and net operating losses if applicable. The state and local income tax provisions of the utility subsidiaries are determined on an individual company basis and recognize the tax benefit of various tax credits and net operating losses, if applicable. The subsidiaries record federal, state and local income taxes payable to or receivable from DTE Energy based on the federal, state and local tax provisions of each company.
Fair Value Measurement	Fair value is defined as the price that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date in a principal or most advantageous market. Fair value is a market-based measurement that is determined based on inputs, which refer broadly to assumptions that market participants use in pricing assets or liabilities. These inputs can be readily observable, market corroborated or generally unobservable inputs. The Company makes certain assumptions it believes that market participants would use in pricing assets or liabilities, including assumptions about risk, and the risks inherent in the inputs to valuation techniques. Credit risk of the Company and its counterparties is incorporated in the valuation of assets and liabilities through the use of credit reserves, the impact of which was immaterial at December 31, 2014 and 2013. The Company believes it uses valuation techniques that maximize the use of observable market-based inputs and minimize the use of unobservable inputs.
	A fair value hierarchy has been established that prioritizes the inputs to valuation techniques used to measure fair value in three broad levels. The fair value hierarchy gives the highest priority to quoted prices (unadjusted) in active markets for identical assets or liabilities (Level 1) and the lowest priority to unobservable inputs (Level 3). In some cases, the inputs used to measure fair value might fall in different levels of the fair value hierarchy. All assets and liabilities are required to be classified in their entirety based on the lowest level of input that is significant to the fair value measurement in its entirety. Assessing the significance of a particular input may require judgment considering factors specific to the asset or liability, and may affect the valuation of the asset or liability and its placement within the fair value hierarchy. The Company classifies fair value balances based on the fair value hierarchy defined as follows:
	•	Level 1 — Consists of unadjusted quoted prices in active markets for identical assets or liabilities that the Company has the ability to access as of the reporting date.
	•	Level 2 — Consists of inputs other than quoted prices included within Level 1 that are directly observable for the asset or liability or indirectly observable through corroboration with observable market data.
	•	Level 3 — Consists of unobservable inputs for assets or liabilities whose fair value is estimated based on internally developed models or methodologies using inputs that are generally less readily observable and supported by little, if any, market activity at the measurement date. Unobservable inputs are developed based on the best available information and subject to cost-benefit constraints.
Nuclear Decommissioning Trust and Other Investments	The nuclear decommissioning trusts and other investments hold debt and equity securities directly and indirectly through institutional mutual funds. Exchange-traded debt and equity securities held directly are valued using quoted market prices in actively traded markets. The institutional mutual funds hold exchange-traded equity or debt securities and are valued based on stated NAVs. Non-exchange-traded fixed income securities are valued based upon quotations available from brokers or pricing services. A primary price source is identified by asset type, class or issue for each security. The trustee monitors prices supplied by pricing services and may use a supplemental price source or change the primary price source of a given security if the trustee determines that another price source is considered to be preferable. DTE Energy has obtained an understanding of how these prices are derived, including the nature and observability of the inputs used in deriving such prices. Additionally, DTE Energy selectively corroborates the fair value of securities by comparison of market-based price sources. Investment policies and procedures are determined by the Company's Trust Investments Department which reports to the Company's Vice President and Treasurer.
Derivatives Reporting of Derivative Activity	Derivative assets and liabilities are comprised of physical and financial derivative contracts, including futures, forwards, options and swaps that are both exchange-traded and over-the-counter traded contracts. Various inputs are used to value derivatives depending on the type of contract and availability of market data. Exchange-traded derivative contracts are valued using quoted prices in active markets. DTE Energy considers the following criteria in determining whether a market is considered active: frequency in which pricing information is updated, variability in pricing between sources or over time and the availability of public information. Other derivative contracts are valued based upon a variety of inputs including commodity market prices, broker quotes, interest rates, credit ratings, default rates, market-based seasonality and basis differential factors. DTE Energy monitors the prices that are supplied by brokers and pricing services and may use a supplemental price source or change the primary price source of an index if prices become unavailable or another price source is determined to be more representative of fair value. DTE Energy has obtained an understanding of how these prices are derived. Additionally, DTE Energy selectively corroborates the fair value of its transactions by comparison of market-based price sources. Mathematical valuation models are used for derivatives for which external market data is not readily observable, such as contracts which extend beyond the actively traded reporting period. The Company has established a Risk Management Committee whose responsibilities include directly or indirectly ensuring all valuation methods are applied in accordance with predefined policies. The development and maintenance of our forward price curves has been assigned to our Risk Management Department, which is separate and distinct from the trading functions within the Company.
Fair Value Transfer	Derivatives are transferred between levels primarily due to changes in the source data used to construct price curves as a result of changes in market liquidity. Transfers in and transfers out are reflected as if they had occurred at the beginning of the period.
Fair Value of Financial Instruments	The fair value of financial instruments included in the table below is determined by using quoted market prices when available. When quoted prices are not available, pricing services may be used to determine the fair value with reference to observable interest rate indexes. DTE Energy has obtained an understanding of how the fair values are derived. DTE Energy also selectively corroborates the fair value of its transactions by comparison of market-based price sources. Discounted cash flow analyses based upon estimated current borrowing rates are also used to determine fair value when quoted market prices are not available. The fair values of notes receivable, excluding capital leases, are estimated using discounted cash flow techniques that incorporate market interest rates as well as assumptions about the remaining life of the loans and credit risk. Depending on the information available, other valuation techniques may be used that rely on internal assumptions and models. Valuation policies and procedures are determined by DTE Energy's Treasury Department which reports to the Company's Vice President and Treasurer.
Derivatives	The Company recognizes all derivatives at their fair value as Derivative assets or liabilities on the Consolidated Statements of Financial Position unless they qualify for certain scope exceptions, including the normal purchases and normal sales exception. Further, derivatives that qualify and are designated for hedge accounting are classified as either hedges of a forecasted transaction or the variability of cash flows to be received or paid related to a recognized asset or liability (cash flow hedge), or as hedges of the fair value of a recognized asset or liability or of an unrecognized firm commitment (fair value hedge). For cash flow hedges, the portion of the derivative gain or loss that is effective in offsetting the change in the value of the underlying exposure is deferred in Accumulated other comprehensive income and later reclassified into earnings when the underlying transaction occurs. Gains or losses from the ineffective portion of cash flow hedges are recognized in earnings immediately. For fair value hedges, changes in fair values for the derivative and hedged item are recognized in earnings each period. For derivatives that do not qualify or are not designated for hedge accounting, changes in the fair value are recognized in earnings each period.
	The Company’s primary market risk exposure is associated with commodity prices, credit and interest rates. The Company has risk management policies to monitor and manage market risks. The Company uses derivative instruments to manage some of the exposure. The Company uses derivative instruments for trading purposes in its Energy Trading segment. Contracts classified as derivative instruments include electricity, natural gas, oil and certain coal forwards, futures, options and swaps, and foreign currency exchange contracts. Items not classified as derivatives include natural gas inventory, pipeline transportation contracts, renewable energy credits and natural gas storage assets.
Derivatives, Offsetting Fair Value Amounts	Certain of the Company's derivative positions are subject to netting arrangements which provide for offsetting of asset and liability positions as well as related cash collateral. Such netting arrangements generally do not have restrictions. Under such netting arrangements, the Company offsets the fair value of derivative instruments with cash collateral received or paid for those contracts executed with the same counterparty, which reduces the Company's total assets and liabilities. Cash collateral is allocated between the fair value of derivative instruments and customer accounts receivable and payable with the same counterparty on a pro rata basis to the extent there is exposure. Any cash collateral remaining, after the exposure is netted to zero, is reflected in accounts receivable and accounts payable as collateral paid or received, respectively.
	The Company also provides and receives collateral in the form of letters of credit which can be offset against net derivative assets and liabilities as well as accounts receivable and payable. The Company had issued letters of credit of approximately $7 million and $19 million at December 31, 2014 and 2013, respectively, which could be used to offset net derivative liabilities. Letters of credit received from third parties which could be used to offset our net derivative assets were approximately $5 million and $1 million at December 31, 2014 and 2013, respectively. Such balances of letters of credit are excluded from the tables below and are not netted with the recognized assets and liabilities in the Consolidated Statements of Financial Position.
	For contracts with certain clearing agents the fair value of derivative instruments is netted against realized positions with the net balance reflected as either 1) a derivative asset or liability or 2) an account receivable or payable. Other than certain clearing agents, accounts receivable and accounts payable that are subject to netting arrangements have not been offset against the fair value of derivative assets and liabilities. Certain contracts that have netting arrangements have not been offset in the Consolidated Statements of Financial Position. The impact of netting these derivative instruments and cash collateral related to such contracts is not material. Only the gross amounts for these derivative instruments are included in the table below.
Derivatives, Methods of Accounting, Derivatives Not Designated or Qualifying as Hedges	Revenues and energy costs related to trading contracts are presented on a net basis in the Consolidated Statements of Operations. Commodity derivatives used for trading purposes, and financial non-trading commodity derivatives, are accounted for using the MTM method with unrealized and realized gains and losses recorded in Operating revenues. Non-trading physical commodity sale and purchase derivative contracts are generally accounted for using the MTM method with unrealized and realized gains and losses for sales recorded in Operating revenue and purchases recorded in Fuel, purchased power and gas.
Stock-Based Compensation	The Company records compensation expense at fair value over the vesting period for all awards it grants.

Organization_and_Basis_of_Pres1

Organization and Basis of Presentation (Tables)	12 Months Ended
	Dec. 31, 2014
Variable Interest Entity, Consolidated, Carrying Amount, Assets and Liabilities, Net [Abstract]
Schedule of Variable Interest Entities	The following table summarizes the major balance sheet items for consolidated VIEs as of December 31, 2014 and 2013. All assets and liabilities of a consolidated VIE are presented where it has been determined that a consolidated VIE has either (1) assets that can be used only to settle obligations of the VIE or (2) liabilities for which creditors do not have recourse to the general credit of the primary beneficiary. VIEs, in which the Company holds a majority voting interest and is the primary beneficiary, that meet the definition of a business and whose assets can be used for purposes other than the settlement of the VIE's obligations have been excluded from the table below.
		December 31, 2014						December 31, 2013
		Securitization		Other		Total		Securitization		Other		Total
		(In millions)
	ASSETS
	Cash and cash equivalents	$	—	$	7	$	7	$	—	$	12	$	12
	Restricted cash	96		8		104		100		8		108
	Accounts receivable	26		15		41		34		16		50
	Inventories	—		67		67		—		118		118
	Property, plant and equipment, net	—		81		81		—		99		99
	Securitized regulatory assets	34		—		34		231		—		231
	Other current and long-term assets	1		6		7		4		9		13
		$	157	$	184	$	341	$	369	$	262	$	631
	LIABILITIES
	Accounts payable and accrued current liabilities	$	3	$	8	$	11	$	7	$	23	$	30
	Current portion long-term debt, including capital leases	105		10		115		196		9		205
	Current regulatory liabilities	32		—		32		43		—		43
	Mortgage bonds, notes and other	—		15		15		—		21		21
	Securitization bonds	—		—		—		105		—		105
	Capital lease obligations	—		3		3		—		7		7
	Other current and long-term liabilities	9		6		15		8		6		14
		$	149	$	42	$	191	$	359	$	66	$	425
Summary of Amounts For Nonconsolidated Variable Interest Entities	Amounts for non-consolidated VIEs as of December 31, 2014 and 2013 are as follows:
		31-Dec-14		31-Dec-13
		(In millions)
	Other investments	$	134	$	141
	Notes receivable	$	15	$	8

Significant_Accounting_Policie2

Significant Accounting Policies (Tables)	12 Months Ended
	Dec. 31, 2014
Accounting Policies [Abstract]
Schedule of Accumulated Other Comprehensive Income (Loss)	The following table summarizes the changes in Accumulated other comprehensive loss by component for the years ended December 31, 2014 and 2013:
		Changes in Accumulated Other Comprehensive Loss by Component (a)
		Net			Net			Benefit			Foreign			Total
		Unrealized			Unrealized			Obligations			Currency
		Gain/(Loss)			Gain/(Loss)			(b)			Translation
		on Derivatives			on Investments
		(In millions)
	Balance, January 1, 2013	$	(4	)	$	(8	)	$	(148	)	$	2		$	(158	)
	Other comprehensive income (loss) before reclassifications	—			2			13			(2		)	13
	Amounts reclassified from accumulated other comprehensive income	—			—			9			—			9
	Net current-period other comprehensive income (loss)	—			2			22			(2		)	22
	Balance, December 31, 2013	$	(4	)	$	(6	)	$	(126	)	$	—		$	(136	)
	Other comprehensive income (loss) before reclassifications	—			1			(25		)	(2		)	(26		)
	Amounts reclassified from accumulated other comprehensive income	—			—			7			—			7
	Net current-period other comprehensive income (loss)	—			1			(18		)	(2		)	(19		)
	Balance, December 31, 2014	$	(4	)	$	(5	)	$	(144	)	$	(2	)	$	(155	)
	______________________________________
	(a)All amounts are net of tax.
	(b)	The amounts reclassified from accumulated other comprehensive income (loss) are included in the computation of the net periodic pension and other postretirement benefit costs (see Note 18 to the Consolidated Financial Statements "Retirement Benefits and Trusteed Assets").
Schedule of Finite-Lived Intangible Assets by Major Class	The Company has certain intangible assets relating to emission allowances, renewable energy credits and non-utility contracts as shown below:
		December 31, 2014			December 31, 2013
		(In millions)
	Emission allowances	$	1		$	2
	Renewable energy credits	45			51
	Contract intangible assets	122			126
		168			179
	Less accumulated amortization	57			45
	Intangible assets, net	111			134
	Less current intangible assets	9			12
		$	102		$	122
Schedule of Finite-Lived Intangible Assets, Future Amortization Expense	The following table summarizes the estimated amortization expense expected to be recognized during each year through 2019:
	Estimated amortization expense	(In millions)
	2015	$	12
	2016	$	11
	2017	$	8
	2018	$	8
	2019	$	6

Discontinued_Operations_Tables

Discontinued Operations (Tables)	12 Months Ended
	Dec. 31, 2014
Discontinued Operations and Disposal Groups [Abstract]
Schedule of Disposal Groups, Including Discontinued Operations, Income Statement, Balance Sheet and Additional Disclosures	The activity of the discontinued business is shown below. The amounts exclude general corporate overhead costs, and related tax effects, and no portion of corporate interest costs were allocated to discontinued operations.
		2012
		(In millions)
	Operating Revenues	$	55
	Operation and maintenance	24
	Depreciation, depletion and amortization	23
	Taxes other than income	4
	Asset (gains) losses, net	83
		134
	Operating Loss	(79		)
	Other (Income) and Deductions	6
	Loss Before Income Taxes	(85		)
	Income Tax Benefit	(29		)
	Net Loss Attributable to DTE Energy Company	$	(56	)

Property_Plant_and_Equipment_T

Property, Plant and Equipment (Tables)	12 Months Ended
	Dec. 31, 2014
Property, Plant and Equipment [Abstract]
Schedule of Property, Plant and Equipment	Summary of property by classification as of December 31:
		2014				2013
		(In millions)
	Property, Plant and Equipment
	DTE Electric
	Generation	$	11,641			$	11,127
	Distribution	8,164				7,603
	Total DTE Electric	19,805				18,730
	DTE Gas
	Distribution	2,946				2,834
	Storage	448				431
	Other	863				836
	Total DTE Gas	4,257				4,101
	Non-utility and other	2,476				2,292
	Total	26,538				25,123
	Less Accumulated Depreciation, Depletion and Amortization
	DTE Electric
	Generation	(4,149		)		(4,004		)
	Distribution	(3,067		)		(2,947		)
	Total DTE Electric	(7,216		)		(6,951		)
	DTE Gas
	Distribution	(1,130		)		(1,129		)
	Storage	(142		)		(138		)
	Other	(363		)		(338		)
	Total DTE Gas	(1,635		)		(1,605		)
	Non-utility and other	(867		)		(767		)
	Total	(9,718		)		(9,323		)
	Net Property, Plant and Equipment	$	16,820			$	15,800
	The average estimated useful life for each major class of utility property, plant and equipment as of December 31, 2014 follows:
			Estimated Useful Lives in Years
	Utility		Generation		Distribution		Storage
	Electric		40		41		N/A
	Gas		N/A		50		53

Jointly_Owned_Utility_Plant_Ta

Jointly Owned Utility Plant (Tables)	12 Months Ended
	Dec. 31, 2014
Jointly Owned Utility Plant, Net Ownership Amount [Abstract]
Schedule of Jointly Owned Utility Plants	Ownership information of the two utility plants as of December 31, 2014 was as follows:
		Belle River			Ludington
					Hydroelectric
					Pumped Storage
	In-service date	1984-1985			1973
	Total plant capacity	1,270		MW	1,872		MW
	Ownership interest	(a)			49		%
	Investment in property, plant and equipment (in millions)	$	1,742		$	412
	Accumulated depreciation (in millions)	$	993		$	175
	_______________________________________
	(a)	DTE Electric's ownership interest is 63% in Unit No. 1, 81% of the facilities applicable to Belle River used jointly by the Belle River and St. Clair Power Plants and 75% in common facilities used at Unit No. 2.

Asset_Retirement_Obligations_T

Asset Retirement Obligations (Tables)	12 Months Ended
	Dec. 31, 2014
Asset Retirement Obligation Disclosure [Abstract]
Schedule of Change in Asset Retirement Obligation	A reconciliation of the asset retirement obligations for 2014 follows:
		(In millions)
	Asset retirement obligations at December 31, 2013	$	1,827
	Accretion	112
	Liabilities incurred	11
	Liabilities settled	(12		)
	Revision in estimated cash flows	24
	Asset retirement obligations at December 31, 2014	$	1,962

Regulatory_Matters_Tables

Regulatory Matters (Tables)	12 Months Ended
	Dec. 31, 2014
Regulatory Assets and Liabilities Disclosure [Abstract]
Schedule of Regulatory Assets	The following are balances and a brief description of the regulatory assets and liabilities at December 31:
		2014			2013
		(In millions)
	Assets
	Recoverable pension and other postretirement costs:
	Pension	$	2,284		$	1,660
	Other postretirement costs	234			—
	Asset retirement obligation	448			394
	Recoverable Michigan income taxes	267			286
	Unamortized loss on reacquired debt	67			63
	Other recoverable income taxes	66			71
	Accrued PSCR/GCR revenue	61			—
	Deferred environmental costs	59			59
	Cost to achieve Performance Excellence Process	54			75
	Recoverable income taxes related to securitized regulatory assets	19			126
	Removal costs asset	15			—
	Transitional Reconciliation Mechanism	14			—
	Other	139			129
		3,727			2,863
	Less amount included in current assets	(76		)	(26		)
		$	3,651		$	2,837
	Securitized regulatory assets	$	34		$	231
Schedule of Regulatory Liabilities
	Liabilities
	Removal costs liability	$	308		$	351
	Renewable energy	227			277
	Over recovery of Securitization	71			72
	Refundable revenue decoupling/deferred gain	67			127
	Negative pension offset	67			84
	Refundable income taxes	33			45
	Energy optimization	24			31
	Fermi 2 refueling outage	16			26
	Refundable other postretirement costs	—			72
	Accrued PSCR/GCR refund	—			65
	Other	7			14
		$	820		$	1,164
	Less amount included current liabilities	(153		)	(302		)
		$	667		$	862

Income_Taxes_Tables

Income Taxes (Tables)	12 Months Ended
	Dec. 31, 2014
Income Tax Disclosure [Abstract]
Schedule of Effective Income Tax Rate Reconciliation	Total income tax expense varied from the statutory federal income tax rate for the following reasons:
		2014			2013			2012
		(In millions)
	Income before income taxes	$	1,275		$	922		$	960
	Income tax expense at 35% statutory rate	$	446		$	323		$	336
	Production tax credits	(119		)	(68		)	(49		)
	Investment tax credits	(6		)	(6		)	(6		)
	Depreciation	(4		)	(4		)	(4		)
	AFUDC - Equity	(7		)	(5		)	(4		)
	Employee Stock Ownership Plan dividends	(4		)	(4		)	(4		)
	Domestic production activities deduction	—			(14		)	(14		)
	State and local income taxes, net of federal benefit	51			37			37
	Enactment of New York Corporate Income Tax Legislation, net of federal benefit	8			—			—
	Other, net	(1		)	(5		)	(6		)
	Income tax expense	$	364		$	254		$	286
	Effective income tax rate	28.5		%	27.5		%	29.8		%
Schedule of Components of Income Tax Expense (Benefit)	Components of income tax expense were as follows:
		2014			2013			2012
		(In millions)
	Current income tax expense (benefit)
	Federal	$	(16	)	$	74		$	190
	State and other income tax	24			16			49
	Total current income taxes	8			90			239
	Deferred income tax expense
	Federal	289			122			39
	State and other income tax	67			42			8
	Total deferred income taxes	356			164			47
	Total income taxes from continuing operations	364			254			286
	Discontinued operations	—			—			(29		)
	Total	$	364		$	254		$	257
Schedule of Deferred Tax Assets and Liabilities	Deferred tax assets (liabilities) were comprised of the following at December 31:
		2014			2013
		(In millions)
	Property, plant and equipment	$	(3,832	)	$	(3,372	)
	Securitized regulatory assets	(2		)	(127		)
	Tax credit carry-forwards	296			266
	Pension and benefits	(152		)	(30		)
	State net operating loss and credit carry-forwards	39			43
	Other	(19		)	(92		)
		(3,670		)	(3,312		)
	Less valuation allowance	(31		)	(37		)
		$	(3,701	)	$	(3,349	)
	Current deferred income tax assets (liabilities)	$	75		$	(28	)
	Long-term deferred income tax liabilities	(3,776		)	(3,321		)
		$	(3,701	)	$	(3,349	)
	Deferred income tax assets	$	861		$	934
	Deferred income tax liabilities	(4,562		)	(4,283		)
		$	(3,701	)	$	(3,349	)
Schedule of Unrecognized Tax Benefits Roll Forward	A reconciliation of the beginning and ending amount of unrecognized tax benefits is as follows:
		2014			2013			2012
		(In millions)
	Balance at January 1	$	10		$	11		$	48
	Reductions for tax positions of prior years	—			—			(2		)
	Additions for tax positions of current year	—			—			1
	Settlements	—			—			(30		)
	Lapse of statute of limitations	(1		)	(1		)	(6		)
	Balance at December 31	$	9		$	10		$	11

Earnings_Per_Share_Tables

Earnings Per Share (Tables)	12 Months Ended
	Dec. 31, 2014
Earnings Per Share [Abstract]
Schedule of Earnings Per Share, Basic and Diluted	A reconciliation of both calculations is presented in the following table as of December 31:
		2014		2013		2012
		(In millions, expect per share amounts)
	Basic Earnings per Share
	Net income attributable to DTE Energy Company	$	905	$	661	$	610
	Average number of common shares outstanding	177		175		171
	Weighted average net restricted shares outstanding	—		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	2.42		1.17		1.14
	Total Basic Earnings per Common Share	$	5.11	$	3.76	$	3.56
	Diluted Earnings per Share
	Net income attributable to DTE Energy Company	$	905	$	661	$	610
	Average number of common shares outstanding	177		175		171
	Average incremental shares from assumed exercise of options	—		—		1
	Common shares for dilutive calculation	177		175		172
	Weighted average net restricted shares outstanding	—		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	2.41		1.17		1.13
	Total Diluted Earnings per Common Share	$	5.1	$	3.76	$	3.55

Fair_Value_Tables

Fair Value (Tables)	12 Months Ended
	Dec. 31, 2014
Fair Value Disclosures [Abstract]
Assets and Liabilities Recorded at Fair Value on a Recurring Basis	The following table presents assets and liabilities measured and recorded at fair value on a recurring basis as of December 31, 2014 and 2013:
		31-Dec-14																			31-Dec-13
		Level 1			Level 2				Level 3				Netting (a)				Net Balance				Level 1				Level 2			Level 3			Netting (a)			Net Balance
		(In millions)
	Assets:
	Cash equivalents (b)	$	13		$	99			$	—			$	—			$	112			$	10			$	115		$	—		$	—		$	125
	Nuclear decommissioning trusts	792			449				—				—				1,241				779				412			—			—			1,191
	Other investments (c) (d)	100			50				—				—				150				92				44			—			—			136
	Derivative assets:
	Commodity Contracts:
	Natural Gas	555			140				92				(681		)		106				273				89			34			(382		)	14
	Electricity	—			295				47				(280		)		62				—				261			139			(291		)	109
	Other	42			—				3				(42		)		3				33				1			3			(34		)	3
	Other derivative contracts (e)	—			4				—				(3		)		1				—				—			—			—			—
	Total derivative assets	597			439				142				(1,006		)		172				306				351			176			(707		)	126
	Total	$	1,502		$	1,037			$	142			$	(1,006	)		$	1,675			$	1,187			$	922		$	176		$	(707	)	$	1,578
	Liabilities:
	Derivative liabilities:
	Commodity Contracts:
	Natural Gas	$	(578	)	$	(78	)		$	(62	)		$	679			$	(39	)		$	(277	)		$	(140	)	$	(86	)	$	395		$	(108	)
	Electricity	—			(290		)		(52		)		298				(44		)		—				(272		)	(126		)	269			(129		)
	Other	(32		)	(9		)		(4		)		45				—				(32		)		(2		)	—			34			—
	Other derivative contracts (e)	—			(5		)		—				3				(2		)		—				(1		)	—			—			(1		)
	Total derivative liabilities	(610		)	(382		)		(118		)		1,025				(85		)		(309		)		(415		)	(212		)	698			(238		)
	Total	$	(610	)	$	(382	)		$	(118	)		$	1,025			$	(85	)		$	(309	)		$	(415	)	$	(212	)	$	698		$	(238	)
	Net Assets (Liabilities) at the end of the period	$	892		$	655			$	24			$	19			$	1,590			$	878			$	507		$	(36	)	$	(9	)	$	1,340
	Assets:
	Current	$	582		$	504			$	109			$	(955	)		$	240			$	277			$	400		$	139		$	(592	)	$	224
	Noncurrent (f)	920			533				33				(51		)		1,435				910				522			37			(115		)	1,354
	Total Assets	$	1,502		$	1,037			$	142			$	(1,006	)		$	1,675			$	1,187			$	922		$	176		$	(707	)	$	1,578
	Liabilities:
	Current	$	(572	)	$	(357	)		$	(112	)		$	964			$	(77	)		$	(268	)		$	(328	)	$	(177	)	$	578		$	(195	)
	Noncurrent	(38		)	(25		)		(6		)		61				(8		)		(41		)		(87		)	(35		)	120			(43		)
	Total Liabilities	$	(610	)	$	(382	)		$	(118	)		$	1,025			$	(85	)		$	(309	)		$	(415	)	$	(212	)	$	698		$	(238	)
	Net Assets (Liabilities) at the end of the period	$	892		$	655			$	24			$	19			$	1,590			$	878			$	507		$	(36	)	$	(9	)	$	1,340
	_______________________________________
	(a)	Amounts represent the impact of master netting agreements that allow the Company to net gain and loss positions and cash collateral held or placed with the same counterparties.
	(b)	At December 31, 2014, available-for-sale securities of $112 million included $105 million and $7 million of cash equivalents included in Restricted cash and Other investments on the Consolidated Statements of Financial Position, respectively. At December 31, 2013, available-for-sale securities of $125 million, included $109 million and $16 million of cash equivalents included in Restricted cash and Other investments on the Consolidated Statements of Financial Position, respectively.
	(c)	Excludes cash surrender value of life insurance investments.
	(d)	Available-for-sale equity securities of $8 million at December 31, 2014 and $7 million at December 31, 2013 are included in Other investments on the Consolidated Statements of Financial Position.
	(e)	Primarily includes Foreign currency exchange contracts.
	(f)	Includes $150 million and $136 million of Other investments that are included in the Consolidated Statements of Financial Position in Other investments at December 31, 2014 and 2013, respectively.
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis Level 3 Roll Forward	The following table presents the fair value reconciliation of Level 3 assets and liabilities measured at fair value on a recurring basis for the years ended December 31, 2014 and 2013:
		Year Ended December 31, 2014															Year Ended December 31, 2013
		Natural Gas			Electricity				Other				Total				Natural Gas				Electricity				Other			Total
		(In millions)
	Net Assets (Liabilities) as of December 31	$	(52	)	$	13			$	3			$	(36	)		$	(38	)		$	23			$	2		$	(13	)
	Transfers into Level 3 from Level 2	—			—				—				—				1				—				—			1
	Transfers from Level 3 into Level 2	(2		)	—				—				(2		)		—				—				—			—
	Total gains (losses):
	Included in earnings	(40		)	25				(5		)		(20		)		(32		)		75				—			43
	Recorded in regulatory assets/liabilities	—			—				8				8				—				—				5			5
	Purchases, issuances and settlements:
	Purchases	—			1				—				1				(8		)		1				—			(7		)
	Issuances	—			(3		)		—				(3		)		—				(1		)		—			(1		)
	Settlements	124			(41		)		(7		)		76				25				(85		)		(4		)	(64		)
	Net Assets (Liabilities) as of December 31	$	30		$	(5	)		$	(1	)		$	24			$	(52	)		$	13			$	3		$	(36	)
	The amount of total gains (losses) included in net income attributed to the change in unrealized gains (losses) related to assets and liabilities held at December 31, 2014 and 2013 and reflected in Operating revenues and Fuel, purchased power and gas in the Consolidated Statements of Operations	$	35		$	9			$	(4	)		$	40			$	(49	)		$	48			$	—		$	(1	)
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques	The following tables present the unobservable inputs related to Level 3 assets and liabilities as of December 31, 2014 and 2013:
			December 31, 2014
	Commodity Contracts		Derivative Assets			Derivative Liabilities				Valuation Techniques		Unobservable Input		Range								Weighted Average
			(In millions)
	Natural Gas		$	92		$	(62	)		Discounted Cash Flow		Forward basis price (per MMBtu)		$	(2.28	) —		$	7.83	/MMBtu		$	(0.22	)/MMBtu
	Electricity		$	47		$	(52	)		Discounted Cash Flow		Forward basis price (per MWh)		$	(14	) —		$	15	/MWh		$	4	/MWh
			December 31, 2013
	Commodity Contracts		Derivative Assets			Derivative Liabilities				Valuation Techniques		Unobservable Input		Range								Weighted Average
			(In millions)
	Natural Gas		$	34		$	(86	)		Discounted Cash Flow		Forward basis price (per MMBtu)		$	(0.88	) —		$	5.07	/MMBtu		$	(0.16	)/MMBtu
	Electricity		$	139		$	(126	)		Discounted Cash Flow		Forward basis price (per MWh)		$	(7	) —		$	15	/MWh		$	3	/MWh
Fair Value of Financial Instruments	The following table presents the carrying amount and fair value of financial instruments as of December 31, 2014 and 2013:
		December 31, 2014															December 31, 2013
		Carrying			Fair Value												Carrying				Fair Value
		Amount			Level 1				Level 2				Level 3				Amount				Level 1				Level 2			Level 3
		(In millions)
	Notes receivable, excluding capital leases	$	41		$	—			$	—			$	41			$	41			$	—			$	—		$	41
	Dividends payable	$	122		$	122			$	—			$	—			$	116			$	116			$	—		$	—
	Short-term borrowings	$	398		$	—			$	398			$	—			$	131			$	—			$	131		$	—
	Long-term debt, excluding capital leases	$	8,606		$	489			$	8,308			$	706			$	8,094			$	425			$	7,551		$	499
Fair Value of Nuclear Decommissioning Trust Fund Assets Text Block	The following table summarizes the fair value of the nuclear decommissioning trust fund assets:
		31-Dec-14			31-Dec-13
		(In millions)
	Fermi 2	$	1,221		$	1,172
	Fermi 1	3			3
	Low level radioactive waste	17			16
	Total	$	1,241		$	1,191
Schedule of Realized Gain (Loss)	The following table sets forth the gains and losses and proceeds from the sale of securities by the nuclear decommissioning trust funds:
		Year Ended December 31
		2014			2013				2012
		(In millions)
	Realized gains	$	54		$	83			$	37
	Realized losses	$	(33	)	$	(41	)		$	(31	)
	Proceeds from sales of securities	$	1,146		$	1,118			$	759
Fair Value and Unrealized Gains and Losses for Nuclear Decommissioning Trust Fund Table	The following table sets forth the fair value and unrealized gains for the nuclear decommissioning trust funds:
		31-Dec-14											31-Dec-13
		Fair			Unrealized				Unrealized Losses				Fair				Unrealized				Unrealized Losses
		Value			Gains								Value				Gains
		(In millions)
	Equity securities	$	756		$	204			$	(39	)		$	730			$	201			$	(25	)
	Debt securities	474			21				(2		)		442				12				(6		)
	Cash and cash equivalents	11			—				—				19				—				—
		$	1,241		$	225			$	(41	)		$	1,191			$	213			$	(31	)

Financial_and_Other_Derivative1

Financial and Other Derivative Instruments (Tables)	12 Months Ended
	Dec. 31, 2014
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Fair Value of Derivative Instruments	The following tables present the fair value of derivative instruments as of December 31, 2014 and 2013:
		December 31, 2014								December 31, 2013
		Derivative				Derivative Liabilities				Derivative			Derivative Liabilities
		Assets								Assets
		(In millions)
	Derivatives not designated as hedging instruments:
	Foreign currency exchange contracts	$	4			$	(5	)		$	—		$	(1	)
	Commodity Contracts:
	Natural Gas	787				(718		)		396			(503		)
	Electricity	342				(342		)		400			(398		)
	Other	45				(45		)		37			(34		)
	Total derivatives not designated as hedging instruments:	$	1,178			$	(1,110	)		$	833		$	(936	)
	Total derivatives:
	Current	$	1,083			$	(1,041	)		$	691		$	(773	)
	Noncurrent	95				(69		)		142			(163		)
	Total derivatives	$	1,178			$	(1,110	)		$	833		$	(936	)
Netting Offsets of Derivative Assets and Liabilities	The following table presents the netting offsets of derivative assets and liabilities at December 31, 2014 and 2013:
		31-Dec-14											31-Dec-13
		Gross Amounts of Recognized Assets (Liabilities)				Gross Amounts Offset in the Consolidated Statements of Financial Position				Net Amounts of Assets (Liabilities) Presented in the Consolidated Statements of Financial Position			Gross Amounts of Recognized Assets (Liabilities)			Gross Amounts Offset in the Consolidated Statements of Financial Position			Net Amounts of Assets (Liabilities) Presented in the Consolidated Statements of Financial Position
		(In millions)
	Derivative assets:
	Commodity Contracts:
	Natural Gas	$	787			$	(681	)		$	106		$	396		$	(382	)	$	14
	Electricity	342				(280		)		62			400			(291		)	109
	Other	45				(42		)		3			37			(34		)	3
	Other derivative contracts (a)	4				(3		)		1			—			—			—
	Total derivative assets	$	1,178			$	(1,006	)		$	172		$	833		$	(707	)	$	126
	Derivative liabilities:
	Commodity Contracts:
	Natural Gas	$	(718	)		$	679			$	(39	)	$	(503	)	$	395		$	(108	)
	Electricity	(342		)		298				(44		)	(398		)	269			(129		)
	Other	(45		)		45				—			(34		)	34			—
	Other derivative contracts (a)	(5		)		3				(2		)	(1		)	—			(1		)
	Total derivative liabilities	$	(1,110	)		$	1,025			$	(85	)	$	(936	)	$	698		$	(238	)
	_______________________________________
	(a)	Primarily includes Foreign currency exchange contracts
Netting Offsets of Derivative Assets and Liabilities Reconciliation to the Statements of Financial Position	The following table presents the netting offsets of derivative assets and liabilities at December 31, 2014 and 2013:
		December 31, 2014														31-Dec-13
		Derivative Assets								Derivative Liabilities						Derivative Assets						Derivative Liabilities
		Current				Noncurrent				Current			Noncurrent			Current			Noncurrent			Current			Noncurrent
		(In millions)
	Reconciliation of derivative instruments to Consolidated Statements of Financial Position:
	Total fair value of derivatives	$	1,083			$	95			$	(1,041	)	$	(69	)	$	691		$	142		$	(773	)	$	(163	)
	Counterparty netting	(955		)		(51		)		955			51			(566		)	(115		)	566			115
	Collateral adjustment	—				—				9			10			(26		)	—			12			5
	Total derivatives as reported	$	128			$	44			$	(77	)	$	(8	)	$	99		$	27		$	(195	)	$	(43	)
Gain (Loss) Recognized in Income on Derivative	The effect of derivatives not designated as hedging instruments on the Consolidated Statements of Operations for years ended December 31, 2014 and 2013 is as follows:
			Location of Gain (Loss) Recognized in Income on Derivatives		Gain (Loss) Recognized in
					Income on Derivatives for
					Years Ended December 31,
	Derivatives not Designated as Hedging Instruments				2014				2013
					(In millions)
	Foreign currency exchange contracts		Operating Revenue		$	(2	)		$	(1	)
	Commodity Contracts:
	Natural Gas		Operating Revenue		(30		)		(48		)
	Natural Gas		Fuel, purchased power and gas		(5		)		(44		)
	Electricity		Operating Revenue		123				82
	Other		Operating Revenue		(7		)		—
	Total				$	79			$	(11	)
Volume of Commodity Contracts	The following represents the cumulative gross volume of derivative contracts outstanding as of December 31, 2014:
	Commodity		Number of Units
	Natural Gas (MMBtu)		895,599,953
	Electricity (MWh)		11,296,153
	Foreign Currency Exchange (Canadian dollars)		63,022,462

LongTerm_Debt_Tables

Long-Term Debt (Tables)	12 Months Ended
	Dec. 31, 2014
Long-term Debt, Unclassified [Abstract]
Schedule of Long-term Debt Instruments	The Company’s long-term debt outstanding and weighted average interest rates (a) of debt outstanding at December 31 were:
		2014				2013
		(In millions)
	Mortgage bonds, notes and other
	DTE Energy Debt, Unsecured
	4.6% due 2016 to 2033	$	1,647			$	1,297
	DTE Electric Taxable Debt, Principally Secured
	4.5% due 2016 to 2044	4,824				4,286
	DTE Electric Tax-Exempt Revenue Bonds (b)
	5.2% due 2020 to 2030	330				558
	DTE Gas Taxable Debt, Principally Secured
	5.2% due 2015 to 2044	1,099				1,029
	Other Long-Term Debt, Including Non-Recourse Debt	121				142
		8,021				7,312
	Less amount due within one year	(161		)		(694		)
		$	7,860			$	6,618
	Securitization bonds
	6.6% due 2015	$	105			$	302
	Less amount due within one year	(105		)		(197		)
		$	—			$	105
	Junior Subordinated Debentures
	6.5% due 2061	$	280			$	280
	5.25% due 2062	200				200
		$	480			$	480
	_______________________________________
	(a)	Weighted average interest rates as of December 31, 2014 are shown below the description of each category of debt.
	(b)	DTE Electric Tax-Exempt Revenue Bonds are issued by a public body that loans the proceeds to DTE Electric on terms substantially mirroring the Revenue Bonds.
Schedule of Issued Debt	In 2014, the following debt was issued:
	Company		Month Issued		Type		Interest Rate		Maturity		Amount
											(In millions)
	DTE Energy		May		Senior Notes (a)		3.5	%	2024		$	350
	DTE Electric		June		Mortgage Bonds (a)		3.77	%	2026		100
	DTE Electric		June		Mortgage Bonds (a)		4.6	%	2044		150
	DTE Electric		July		Mortgage Bonds (a)		3.375	%	2025		350
	DTE Electric		July		Mortgage Bonds (a)		4.3	%	2044		350
	DTE Energy		November		Senior Notes (a)		2.4	%	2019		300
	DTE Gas		December		Mortgage Bonds (a)		4.35	%	2044		150
											$	1,750
	_______________________________________
	(a)	Proceeds were used for the redemption of long-term debt, repayment of short-term borrowings and general corporate purposes.
Schedule of Extinguishment of Debt	In 2014, the following debt was redeemed:
	Company		Month		Type		Interest Rate		Maturity		Amount
											(In millions)
	DTE Electric		March		Mortgage Bonds		Various		2014		$	13
	DTE Electric		March		Securitization Bonds		6.62	%	2014		100
	DTE Electric		April		Tax Exempt Revenue Bonds (a)		2.35	%	2024		31
	DTE Electric		April		Tax Exempt Revenue Bonds (a)		4.65	%	2028		32
	DTE Gas		May		Mortgage Bonds		8.25	%	2014		80
	DTE Energy		May		Senior Notes		7.625	%	2014		300
	DTE Electric		June		Tax Exempt Revenue Bonds (a)		4.875	%	2029		36
	DTE Electric		June		Tax Exempt Revenue Bonds (a)		6	%	2036		69
	DTE Electric		July		Senior Notes		4.8	%	2015		200
	DTE Electric		August		Senior Notes		5.4	%	2014		200
	DTE Electric		August		Tax Exempt Revenue Bonds (a)		5.25	%	2029		60
	DTE Electric		September		Securitization Bonds		6.62	%	2014		96
	DTE Energy		Various		Other Long Term Debt		Various		2014		20
											$	1,237
	_______________________________________
	(a)	DTE Electric Tax Exempt Revenue Bonds are issued by a public body that loans the proceeds to DTE Electric on terms substantially mirroring the Revenue Bonds.
Schedule of Maturities of Long-term Debt	The following table shows the scheduled debt maturities, excluding any unamortized discount or premium on debt:
		2015				2016			2017				2018		2019		2020 and Thereafter		Total
		(In millions)
	Amount to mature	$	266			$	465		$	9			$	407	$	427	$	7,046	$	8,620

Preferred_and_Preferenced_Secu1

Preferred and Preferenced Securities (Tables)	12 Months Ended
	Dec. 31, 2014
Preferred Stock, Number of Shares, Par Value and Other Disclosures [Abstract]
Schedule of Preferred and Preference Securities	As of December 31, 2014, the amount of authorized and unissued stock is as follows:
	Company	Type of Stock	Par Value		Shares Authorized
	DTE Energy	Preferred	$	—	5,000,000
	DTE Electric	Preferred	$	100	6,747,484
	DTE Electric	Preference	$	1	30,000,000
	DTE Gas	Preferred	$	1	7,000,000
	DTE Gas	Preference	$	1	4,000,000

ShortTerm_Credit_Arrangements_1

Short-Term Credit Arrangements and Borrowings (Tables)	12 Months Ended
	Dec. 31, 2014
Short-term Debt [Abstract]
Schedule of Line of Credit Facilities	The availability under the facilities in place at December 31, 2014 is shown in the following table:
		DTE Energy		DTE Electric		DTE Gas		Total
		(In millions)
	Unsecured letter of credit facility, expiring in February 2015	$	100	$	—	$	—	$	100
	Unsecured letter of credit facility, expiring in August 2015	125		—		—		125
	Unsecured revolving credit facility, expiring April 2018	1,200		300		300		1,800
		1,425		300		300		2,025
	Amounts outstanding at December 31, 2014:
	Commercial paper issuances	203		50		145		398
	Letters of credit	204		—		—		204
		407		50		145		602
	Net availability at December 31, 2014	$	1,018	$	250	$	155	$	1,423

Capital_and_Operating_Leases_T

Capital and Operating Leases (Tables)	12 Months Ended
	Dec. 31, 2014
Leases [Abstract]
Schedule of Future Minimum Rental Payments for Operating Leases	Future minimum lease payments under non-cancelable leases at December 31, 2014 were:
		Operating
		Leases
		(In millions)
	2015	$	42
	2016	34
	2017	28
	2018	23
	2019	14
	Thereafter	78
	Total minimum lease payments	$	219
Schedule of Future Minimum Lease Receivables for Capital Leases	The components of the net investment in the capital leases at December 31, 2014, were as follows:
		Capital
		Leases
		(In millions)
	2015	$	12
	2016	13
	2017	13
	2018	13
	2019	10
	Thereafter	9
	Total minimum future lease receipts	70
	Residual value of leased pipeline	40
	Less unearned income	(34		)
	Net investment in capital lease	76
	Less current portion	(5		)
		$	71

Commitments_and_Contingencies_1

Commitments and Contingencies (Tables)	12 Months Ended
	Dec. 31, 2014
Commitments and Contingencies Disclosure [Abstract]
Schedule of Long-term Purchase Commitment	The Company estimates that these commitments will be approximately $9.0 billion from 2015 through 2051 as detailed in the following table:
		(In millions)
	2015	$	2,384
	2016	1,258
	2017	742
	2018	477
	2019	431
	2020 and thereafter	3,723
		$	9,015

Retirement_Benefits_and_Truste1

Retirement Benefits and Trusteed Assets (Tables)	12 Months Ended
	Dec. 31, 2014
Pension Plan
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Schedule of Net Benefit Costs	Net pension cost includes the following components:
		2014			2013			2012
		(In millions)
	Service cost	$	83		$	94		$	82
	Interest cost	212			192			204
	Expected return on plan assets	(273		)	(266		)	(244		)
	Amortization of:
	Net loss	157			208			176
	Special termination benefits	—			—			2
	Net pension cost	$	179		$	228		$	220
Schedule of Defined Benefit Plan Amounts Recognized in Other Comprehensive Income (Loss) [Table Text Block]
		2014			2013
		(In millions)
	Other changes in plan assets and benefit obligations recognized in Regulatory assets and Other comprehensive income
	Net actuarial (gain) loss	$	805		$	(581	)
	Amortization of net actuarial loss	(157		)	(208		)
	Prior service cost	(7		)	—
	Total recognized in Regulatory assets and Other comprehensive income	$	641		$	(789	)
	Total recognized in net periodic pension cost, Regulatory assets and Other comprehensive income	$	820		$	(561	)
	Estimated amounts to be amortized from Regulatory assets and Accumulated other comprehensive income into net periodic benefit cost during next fiscal year
	Net actuarial loss	$	206		$	151
Schedule of Defined Benefit Plans Disclosures	The following table reconciles the obligations, assets and funded status of the plans as well as the amounts recognized as prepaid pension cost or pension liability in the Consolidated Statements of Financial Position at December 31:
		2014			2013
		(In millions)
	Accumulated benefit obligation, end of year	$	4,853		$	4,068
	Change in projected benefit obligation
	Projected benefit obligation, beginning of year	$	4,380		$	4,729
	Service cost	83			94
	Interest cost	212			192
	Plan amendments	(7		)	(3		)
	Actuarial (gain) loss	836			(400		)
	Benefits paid	(235		)	(232		)
	Projected benefit obligation, end of year	$	5,269		$	4,380
	Change in plan assets
	Plan assets at fair value, beginning of year	$	3,720		$	3,223
	Actual return on plan assets	301			445
	Company contributions	195			284
	Benefits paid	(235		)	(232		)
	Plan assets at fair value, end of year	$	3,981		$	3,720
	Funded status of the plans	$	(1,288	)	$	(660	)
	Amount recorded as:
	Current liabilities	$	(8	)	$	(7	)
	Noncurrent liabilities	(1,280		)	(653		)
		$	(1,288	)	$	(660	)
	Amounts recognized in Accumulated other comprehensive loss, pre-tax
	Net actuarial loss	$	194		$	174
	Prior service (credit)	(1		)	(1		)
		$	193		$	173
	Amounts recognized in Regulatory assets (see Note 8)
	Net actuarial loss	$	2,285		$	1,654
	Prior service (credit) cost	(1		)	6
		$	2,284		$	1,660
Schedule of Expected Benefit Payments	At December 31, 2014, the benefits related to the Company’s qualified and nonqualified pension plans expected to be paid in each of the next five years and in the aggregate for the five fiscal years thereafter are as follows:
		(In millions)
	2015	$	269
	2016	277
	2017	286
	2018	298
	2019	309
	2020-2024	1,634
	Total	$	3,073
Schedule of Assumptions Used	Assumptions used in determining the projected benefit obligation and net pension costs are listed below:
		2014		2013	2012
	Projected benefit obligation
	Discount rate	4.12%		4.95%	4.15%
	Rate of compensation increase	4.65%		4.20%	4.20%
	Net pension costs
	Discount rate	4.95%		4.15%	5.00%
	Rate of compensation increase	4.20%		4.20%	4.20%
	Expected long-term rate of return on plan assets	7.75%		8.25%	8.25%
Schedule of Allocation of Plan Assets	Target allocations for pension plan assets as of December 31, 2014 are listed below:
	U.S. Large Cap Equity Securities	22	%
	U.S. Small Cap and Mid Cap Equity Securities	5
	Non U.S. Equity Securities	20
	Fixed Income Securities	25
	Hedge Funds and Similar Investments	20
	Private Equity and Other	8
		100	%
	Fair Value Measurements for pension plan assets at December 31, 2014 and 2013 (a):
		December 31, 2014												31-Dec-13
		Level 1			Level 2			Level 3			Total			Level 1			Level 2			Level 3		Total
		(In millions)
	Asset category:
	Short-term investments (b)	$	46		$	—		$	—		$	46		$	22		$	—		$	—	$	22
	Equity securities
	U.S. large cap (c)	899			—			—			899			896			—			—		896
	U.S. small/mid cap (d)	225			—			—			225			221			—			—		221
	Non U.S. (e)	526			219			—			745			611			130			—		741
	Fixed income securities (f)	7			1,113			—			1,120			16			921			—		937
	Hedge funds and similar investments (g)	226			95			438			759			268			70			395		733
	Private equity and other (h)	—			—			187			187			—			—			170		170
	Securities lending (i)	(189		)	(50		)	—			(239		)	—			—			—		—
	Securities lending collateral (i)	189			50			—			239			—			—			—		—
	Total	$	1,929		$	1,427		$	625		$	3,981		$	2,034		$	1,121		$	565	$	3,720
	_______________________________________
	(a)	For a description of levels within the fair value hierarchy see Note 11 to the Consolidated Financial Statements, "Fair Value".
	(b)	This category predominantly represents certain short-term fixed income securities and money market investments that are managed in separate accounts or commingled funds. Pricing for investments in this category are obtained from quoted prices in actively traded markets or valuations from brokers or pricing services.
	(c)	This category comprises both actively and not actively managed portfolios that track the S&P 500 low cost equity index funds. Investments in this category are exchange-traded securities whereby unadjusted quote prices can be obtained. Exchange-traded securities held in a commingled fund are classified as Level 2 assets.
	(d)	This category represents portfolios of small and medium capitalization domestic equities. Investments in this category are exchange-traded securities whereby unadjusted quote prices can be obtained. Exchange-traded securities held in a commingled fund are classified as Level 2 assets.
	(e)	This category primarily consists of portfolios of non-U.S. developed and emerging market equities. Investments in this category are exchange-traded securities whereby unadjusted quote prices can be obtained. Exchange-traded securities held in a commingled fund are classified as Level 2 assets.
	(f)	This category includes corporate bonds from diversified industries, U.S. Treasuries, and mortgage-backed securities. Pricing for investments in this category is obtained from quoted prices in actively traded markets and quotations from broker or pricing services. Non-exchange traded securities and exchange-traded securities held in commingled funds are classified as Level 2 assets.
	(g)	This category utilizes a diversified group of strategies that attempt to capture financial market inefficiencies and includes publicly traded debt and equity, publicly traded mutual funds, commingled and limited partnership funds and non-exchange traded securities. Pricing for Level 1 and Level 2 assets in this category is obtained from quoted prices in actively traded markets and quoted prices from broker or pricing services. Non-exchange traded securities held in commingled funds are classified as Level 2 assets. Valuations for some Level 3 assets in this category may be based on limited observable inputs as there may be little, if any, publicly available pricing.
	(h)	This category includes a diversified group of funds and strategies that primarily invests in private equity partnerships. This category also includes investments in timber and private mezzanine debt. Pricing for investments in this category is based on limited observable inputs as there is little, if any, publicly available pricing. Valuations for assets in this category may be based on discounted cash flow analyses, relevant publicly-traded comparables and comparable transactions.
	(i)	In 2014, DTE Energy began a securities lending program with a third party agent. The program allows the agent to lend certain securities from the Company's pension trusts to selected entities against receipt of collateral (in the form of cash) as provided for and determined in accordance with its securities lending agency agreement.
Schedule of Effect of Significant Unobservable Inputs, Changes in Plan Assets	Fair Value Measurements Using Significant Unobservable Inputs (Level 3):
		Year Ended December 31, 2014									Year Ended December 31, 2013
		Hedge Funds			Private Equity			Total			Hedge Funds			Private Equity			Total
		and Similar			and Other						and Similar			and Other
		Investments									Investments
		(In millions)
	Beginning Balance at January 1	$	395		$	170		$	565		$	339		$	179		$	518
	Total realized/unrealized gains (losses)	22			16			38			40			4			44
	Purchases, sales and settlements:
	Purchases	22			31			53			16			15			31
	Sales	(1		)	(30		)	(31		)	—			(28		)	(28		)
	Ending Balance at December 31	$	438		$	187		$	625		$	395		$	170		$	565
	The amount of total gains for the period attributable to the change in unrealized gains or losses related to assets still held at the end of the period	$	21		$	11		$	32		$	38		$	3		$	41
Other Postretirement Benefit Plan
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Schedule of Net Benefit Costs	Net other postretirement cost includes the following components:
		2014			2013			2012
		(In millions)
	Service cost	$	34		$	47		$	68
	Interest cost	89			88			120
	Expected return on plan assets	(122		)	(110		)	(92		)
	Amortization of:
	Net loss	20			64			80
	Prior service credit	(144		)	(131		)	(25		)
	Net other postretirement cost (credit)	$	(123	)	$	(42	)	$	151
Schedule of Defined Benefit Plan Amounts Recognized in Other Comprehensive Income (Loss) [Table Text Block]
		2014			2013
		(In millions)
	Other changes in plan assets and APBO recognized in Regulatory assets (liabilities) and Other comprehensive income
	Net actuarial (gain) loss	$	192		$	(353	)
	Amortization of net actuarial loss	(20		)	(64		)
	Prior service credit	—			(218		)
	Amortization of prior service credit	144			131
	Total recognized in Regulatory assets (liabilities) and Other comprehensive income	$	316		$	(504	)
	Total recognized in net periodic benefit cost, Regulatory assets (liabilities) and Other comprehensive income	$	193		$	(546	)
	Estimated amounts to be amortized from Regulatory assets (liabilities) and Accumulated other comprehensive income into net periodic benefit cost during next fiscal year
	Net actuarial loss	$	43		$	21
	Prior service credit	$	(126	)	$	(144	)
Schedule of Defined Benefit Plans Disclosures	The following table reconciles the obligations, assets and funded status of the plans including amounts recorded as Accrued postretirement liability in the Consolidated Statements of Financial Position at December 31:
		2014			2013
		(In millions)
	Change in accumulated postretirement benefit obligation
	Accumulated postretirement benefit obligation, beginning of year	$	1,878		$	2,315
	Service cost	34			47
	Interest cost	89			88
	Plan amendments	—			(218		)
	Actuarial (gain) loss	131			(267		)
	Medicare Part D subsidy	—			1
	Benefits paid	(88		)	(88		)
	Accumulated postretirement benefit obligation, end of year	$	2,044		$	1,878
	Change in plan assets
	Plan assets at fair value, beginning of year	$	1,527		$	1,153
	Actual return on plan assets	62			196
	Company contributions	24			264
	Benefits paid	(85		)	(86		)
	Plan assets at fair value, end of year	$	1,528		$	1,527
	Funded status, end of year	$	(516	)	$	(351	)
	Amount recorded as:
	Current liabilities	$	(1	)	$	(1	)
	Noncurrent liabilities	(515		)	(350		)
		$	(516	)	$	(351	)
	Amounts recognized in Accumulated other comprehensive loss, pre-tax
	Net actuarial loss	$	34		$	29
	Prior service credit	(5		)	(10		)
		$	29		$	19
	Amounts recognized in Regulatory assets (liabilities) (see Note 8)
	Net actuarial loss	$	488		$	321
	Prior service credit	(254		)	(393		)
		$	234		$	(72	)
Schedule of Expected Benefit Payments	At December 31, 2014, the benefits expected to be paid, including prescription drug benefits, in each of the next five years and in the aggregate for the five fiscal years thereafter are as follows:
		(In millions)
	2015	$	101
	2016	107
	2017	111
	2018	117
	2019	122
	2020-2024	660
	Total	$	1,218
Schedule of Assumptions Used	Assumptions used in determining the accumulated postretirement benefit obligation and net other postretirement benefit costs are listed below:
		2014		2013	2012
	Accumulated postretirement benefit obligation
	Discount rate	4.10%		4.95%	4.15%
	Health care trend rate pre- and post- 65	7.50 / 6.50%		7.50 / 6.50%	7.00%
	Ultimate health care trend rate	4.50%		4.50%	5.00%
	Year in which ultimate reached pre- and post- 65	2025 / 2024		2025 / 2024	2021
	Other postretirement benefit costs
	Discount rate (prior to interim remeasurement)	4.95%		4.15%	5.00%
	Discount rate (post interim remeasurement)	N/A		4.30%	N/A
	Expected long-term rate of return on plan assets	8.00%		8.25%	8.25%
	Health care trend rate pre- and post- 65	7.50 / 6.50%		7.00%	7.00%
	Ultimate health care trend rate	4.50%		5.00%	5.00%
	Year in which ultimate reached pre- and post- 65	2025 / 2024		2021	2020
Schedule of Allocation of Plan Assets	Target allocations for other postretirement benefit plan assets as of December 31, 2014 are listed below:
	U.S. Large Cap Equity Securities	17	%
	U.S. Small Cap and Mid Cap Equity Securities	4
	Non U.S. Equity Securities	20
	Fixed Income Securities	25
	Hedge Funds and Similar Investments	20
	Private Equity and Other	14
		100	%
	Fair Value Measurements for other postretirement benefit plan assets at December 31, 2014 and 2013 (a):
		December 31, 2014												31-Dec-13
		Level 1			Level 2			Level 3			Total			Level 1			Level 2			Level 3		Total
	Asset category:	(In millions)
	Short-term investments (b)	$	6		$	—		$	—		$	6		$	5		$	—		$	—	$	5
	Equity securities
	U.S. large cap (c)	266			—			—			266			302			—			—		302
	U.S. small/mid cap (d)	149			—			—			149			147			—			—		147
	Non U.S. (e)	222			59			—			281			282			9			—		291
	Fixed income securities (f)	15			360			—			375			17			350			—		367
	Hedge funds and similar investments (g)	107			45			168			320			130			25			159		314
	Private equity and other (h)	—			—			131			131			—			—			101		101
	Securities lending (i)	(141		)	(17		)	—			(158		)	—			—			—		—
	Securities lending collateral (i)	141			17			—			158			—			—			—		—
	Total	$	765		$	464		$	299		$	1,528		$	883		$	384		$	260	$	1,527
	_______________________________________
	(a)	For a description of levels within the fair value hierarchy see Note 11 to the Consolidated Financial Statements, "Fair Value".
	(b)	This category predominantly represents certain short-term fixed income securities and money market investments that are managed in separate accounts or commingled funds. Pricing for investments in this category are obtained from quoted prices in actively traded markets or valuations from brokers or pricing services.
	(c)	This category comprises both actively and not actively managed portfolios that track the S&P 500 low cost equity index funds. Investments in this category are exchange-traded securities whereby unadjusted quote prices can be obtained. Exchange-traded securities held in a commingled fund are classified as Level 2 assets.
	(d)	This category represents portfolios of small and medium capitalization domestic equities. Investments in this category are exchange-traded securities whereby unadjusted quote prices can be obtained. Exchange-traded securities held in a commingled fund are classified as Level 2 assets.
	(e)	This category primarily consists of portfolios of non-U.S. developed and emerging market equities. Investments in this category are exchange-traded securities whereby unadjusted quote prices can be obtained. Exchange-traded securities held in a commingled fund are classified as Level 2 assets.
	(f)	This category includes corporate bonds from diversified industries, U.S. Treasuries, bank loans and mortgage backed securities. Pricing for investments in this category is obtained from quoted prices in actively traded markets and quotations from broker or pricing services. Non-exchange traded securities and exchange-traded securities held in commingled funds are classified as Level 2 assets.
	(g)	This category utilizes a diversified group of strategies that attempt to capture financial market inefficiencies and includes publicly traded debt and equity, publicly traded mutual funds, commingled and limited partnership funds and non-exchange traded securities. Pricing for Level 1 and Level 2 assets in this category is obtained from quoted prices in actively traded markets and quoted prices from broker or pricing services. Non-exchange traded securities held in commingled funds are classified as Level 2 assets. Valuations for some Level 3 assets in this category may be based on limited observable inputs as there may be little, if any, publicly available pricing.
	(h)	This category includes a diversified group of funds and strategies that primarily invests in private equity partnerships. This category also includes investments in timber and private mezzanine debt. Pricing for investments in this category is based on limited observable inputs as there is little, if any, publicly available pricing. Valuations for assets in this category may be based on discounted cash flow analyses, relevant publicly-traded comparables and comparable transactions.
	(i)	In 2014, DTE Energy began a securities lending program with a third party agent. The program allows the agent to lend certain securities from the Company's VEBA trust to selected entities against receipt of collateral (in the form of cash) as provided for and determined in accordance with its securities lending agency agreement.
	Target allocations for other postretirement benefit plan assets as of December 31, 2014 are listed below:
	U.S. Large Cap Equity Securities	17	%
	U.S. Small Cap and Mid Cap Equity Securities	4
	Non U.S. Equity Securities	20
	Fixed Income Securities	25
	Hedge Funds and Similar Investments	20
	Private Equity and Other	14
		100	%
Schedule of Effect of Significant Unobservable Inputs, Changes in Plan Assets	Fair Value Measurements Using Significant Unobservable Inputs (Level 3):
		Year Ended December 31, 2014									Year Ended December 31, 2013
		Hedge Funds			Private Equity			Total			Hedge Funds			Private Equity			Total
		and Similar			and Other						and Similar			and Other
		Investments									Investments
		(In millions)
	Beginning Balance at January 1	$	159		$	101		$	260		$	119		$	86		$	205
	Total realized/unrealized gains (losses)	8			9			17			14			9			23
	Purchases, sales and settlements:
	Purchases	9			33			42			26			15			41
	Sales	(8		)	(12		)	(20		)	—			(9		)	(9		)
	Ending Balance at December 31	$	168		$	131		$	299		$	159		$	101		$	260
	The amount of total gains for the period attributable to the change in unrealized gains or losses related to assets still held at the end of the period	$	7		$	8		$	15		$	14		$	9		$	23

StockBased_Compensation_Tables

Stock-Based Compensation (Tables)	12 Months Ended
	Dec. 31, 2014
Share-based Compensation [Abstract]
Schedule of Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Table Text Block]	The following table summarizes the components of stock-based compensation:
		2014			2013			2012
		(In millions)
	Stock-based compensation expense	$	103		$	99		$	83
	Tax benefit	40			38			33
	Stock-based compensation cost capitalized in property, plant and equipment	16			15			5
Schedule of Share-based Compensation, Stock Options, Activity	The following table summarizes our stock option activity for the year ended December 31, 2014:
		Number of Options		Weighted Average Exercise Price			Aggregate Intrinsic
							Value
							(In millions)
	Options outstanding at December 31, 2013	723,697		$	42.6
	Granted	—		$	—
	Exercised	(268,689	)	$	41.14
	Forfeited or expired	(10,730	)	$	39.41
	Options outstanding and exercisable at December 31, 2014	444,278		$	43.56		$	17
Schedule of Share-based Compensation, Shares Authorized under Stock Option Plans, by Exercise Price Range	The number, weighted average exercise price and weighted average remaining contractual life of options outstanding were as follows:
	Range of Exercise Prices						Number of Options			Weighted Average		Weighted Average
										Exercise Price		Remaining Contractual Life (Years)
	$	27	—	$	38		25,857			$	27.7	4.16
	$	38.01	—	$	42		82,834			$	41.77	3.16
	$	42.01	—	$	45		221,487			$	43.93	4.06
	$	45.01	—	$	50		114,100			$	47.75	2.15
							444,278			$	43.56	3.41
Schedule of Share-based Compensation, Restricted Stock Units Award Activity [Table Text Block]	Stock award activity for the years ended December 31 was:
		2014			2013			2012
	Fair value of awards vested (in millions)	$	11		$	8		$	9
	Restricted common shares awarded	159,590			127,785			167,320
	Weighted average market price of shares awarded	$	70.09		$	64.72		$	53.71
	Compensation cost charged against income (in millions)	$	10		$	23		$	12
Schedule of Share-based Compensation, Restricted Stock and Restricted Stock Units Activity [Table Text Block]	The following table summarizes the Company’s restricted stock awards activity for the year ended December 31, 2014:
		Restricted		Weighted Average
		Stock		Grant Date
				Fair Value
	Balance at December 31, 2013	492,329		$	53.76
	Grants	159,590		$	70.09
	Forfeitures	(16,841	)	$	62.41
	Vested and issued	(218,760	)	$	47.77
	Balance at December 31, 2014	416,318		$	62.82
Share Based Compensation Expense [Table Text Block]	The Company recorded compensation expense for performance share awards as follows:
		2014			2013			2012
		(In millions)
	Compensation expense	$	93		$	77		$	71
	Cash settlements (a)	$	11		$	9		$	4
	Stock settlements (a)	$	61		$	56		$	41
	_______________________________________
	(a)	Sum of cash and stock settlements approximates the intrinsic value of the liability.
Disclosure of Share-based Compensation Arrangements by Share-based Payment Award	The following table summarizes the Company’s performance share activity for the period ended December 31, 2014:
		Performance Shares		Weighted Average
				Grant Date
				Fair Value
	Balance at December 31, 2013	1,608,789		$	—
	Grants	561,335		$	69.32
	Forfeitures	(44,250	)	$	69.16
	Payouts	(571,177	)	$	—
	Balance at December 31, 2014	1,554,697		$	69.32
Schedule of Unrecognized Compensation Cost, Nonvested Awards	As of December 31, 2014, the total unrecognized compensation cost related to non-vested stock incentive plan arrangements and the weighted average recognition period was as follows:
		Unrecognized			Weighted Average
		Compensation			to be Recognized
		Cost
		(In millions)			(In years)
	Stock awards	$	10		1.06
	Performance shares	48			0.98
		$	58		0.99

Segment_and_Related_Informatio1

Segment and Related Information (Tables)	12 Months Ended
	Dec. 31, 2014
Segment Reporting [Abstract]
Schedule of Segment Reporting Information, by Segment	Inter-segment billing for goods and services exchanged between segments is based upon tariffed or market-based prices of the provider and primarily consists of the sale of reduced emissions fuel, power sales and natural gas sales in the following segments:
		2014			2013			2012
		(In millions)
	Electric	$	29		$	26		$	29
	Gas	6			4			4
	Power and Industrial Projects	794			816			801
	Gas Storage and Pipelines	9			3			6
	Energy Trading	33			43			43
	Corporate and Other	3			(24		)	(37		)
	Discontinued Operations	—			—			2
		$	874		$	868		$	848
	Financial data of the business segments follows:
		Operating			Depreciation,			Interest			Interest			Income			Net Income (Loss)			Total			Goodwill		Capital
		Revenue			Depletion &			Income			Expense			Tax Expense (Benefit)			Attributable			Assets					Expenditures and Acquisitions
					Amortization												to DTE
																	Energy
																	Company
		(In millions)
	2014
	Electric	$	5,283		$	933		$	(1	)	$	250		$	296		$	528		$	18,715		$	1,208	$	1,561
	Gas	1,636			99			(7		)	57			78			140			4,283			743		224
	Power and Industrial Projects	2,289			77			(5		)	28			(100		)	90			1,009			26		77
	Gas Storage and Pipelines	203			34			(6		)	22			53			82			884			24		184
	Energy Trading	3,762			1			—			7			77			122			755			17		3
	Corporate and Other	2			1			(48		)	122			(40		)	(57		)	3,209			—		—
	Reclassifications and Eliminations	(874		)	—			57			(57		)	—			—			(881		)	—		—
	Total	$	12,301		$	1,145		$	(10	)	$	429		$	364		$	905		$	27,974		$	2,018	$	2,049
		Operating			Depreciation,			Interest			Interest			Income			Net Income (Loss)			Total			Goodwill		Capital
		Revenue			Depletion &			Income			Expense			Tax Expense (Benefit)			Attributable			Assets					Expenditures and Acquisitions
					Amortization												to DTE
																	Energy
																	Company
		(In millions)
	2013
	Electric	$	5,199		$	902		$	(1	)	$	268		$	252		$	484		$	17,508		$	1,208	$	1,325
	Gas	1,474			95			(7		)	58			77			143			3,938			743		209
	Power and Industrial Projects	1,950			72			(6		)	27			(45		)	66			1,067			26		93
	Gas Storage and Pipelines	132			23			(7		)	18			45			70			824			24		245
	Energy Trading	1,771			1			—			8			(38		)	(58		)	623			17		3
	Corporate and Other	3			1			(51		)	120			(37		)	(44		)	2,945			—		1
	Reclassifications and Eliminations	(868		)	—			63			(63		)	—			—			(970		)	—		—
	Total	$	9,661		$	1,094		$	(9	)	$	436		$	254		$	661		$	25,935		$	2,018	$	1,876
		Operating			Depreciation,			Interest			Interest			Income			Net Income (Loss)			Total			Goodwill		Capital
		Revenue			Depletion &			Income			Expense			Tax Expense (Benefit)			Attributable			Assets					Expenditures and Acquisitions
					Amortization												to DTE
																	Energy
																	Company
		(In millions)
	2012
	Electric	$	5,293		$	827		$	(1	)	$	272		$	280		$	483		$	17,755		$	1,208	$	1,230
	Gas	1,315			92			(7		)	59			50			115			4,059			745		221
	Power and Industrial Projects	1,823			65			(7		)	37			(44		)	42			991			26		281
	Gas Storage and Pipelines	96			8			(8		)	8			39			61			668			22		233
	Energy Trading	1,109			2			—			8			7			12			629			17		1
	Corporate and Other	3			1			(52		)	121			(46		)	(47		)	3,074			—		3
	Reclassifications and Eliminations	(848		)	—			65			(65		)	—			—			(837		)	—		—
	Total from Continuing Operations	$	8,791		$	995		$	(10	)	$	440		$	286		$	666		$	26,339		$	2,018	$	1,969
	Discontinued Operations (Note 4)																(56		)	—			—		49
	Total																$	610		$	26,339		$	2,018	$	2,018

Supplementary_Quarterly_Financ1

Supplementary Quarterly Financial Information (Unaudited ) (Tables)	12 Months Ended
	Dec. 31, 2014
Quarterly Financial Information Disclosure [Abstract]
Schedule of Quarterly Financial Information	Quarterly earnings per share may not equal full year totals, since quarterly computations are based on weighted average common shares outstanding during each quarter.
		First		Second		Third		Fourth		Year
		Quarter		Quarter		Quarter		Quarter
		(In millions, except per share amounts)
	2014
	Operating Revenues	$	3,930	$	2,698	$	2,595	$	3,078	$	12,301
	Operating Income	$	560	$	249	$	239	$	542	$	1,590
	Net Income Attributable to DTE Energy Company	$	326	$	124	$	156	$	299	$	905
	Basic Earnings per Share	$	1.84	$	0.7	$	0.88	$	1.68	$	5.11
	Diluted Earnings per Share	$	1.84	$	0.7	$	0.88	$	1.68	$	5.1
	2013
	Operating Revenues	$	2,516	$	2,225	$	2,387	$	2,533	$	9,661
	Operating Income	$	410	$	223	$	329	$	241	$	1,203
	Net Income Attributable to DTE Energy Company	$	234	$	105	$	198	$	124	$	661
	Basic Earnings per Share	$	1.35	$	0.6	$	1.13	$	0.7	$	3.76
	Diluted Earnings per Share	$	1.34	$	0.6	$	1.13	$	0.7	$	3.76

Valuation_and_Qualifying_Accou1

Valuation and Qualifying Accounts (Tables)	12 Months Ended
	Dec. 31, 2014
Valuation and Qualifying Accounts [Abstract]
Summary of Valuation Allowance	Valuation and Qualifying Accounts
		Year Ending December 31,
		2014			2013			2012
		(In millions)
	Allowance for Doubtful Accounts (shown as deduction from Accounts Receivable in the Consolidated Statements of Financial Position)
	Balance at Beginning of Period	$	55		$	62		$	162
	Additions:
	Charged to costs and expenses	95			94			79
	Charged to other accounts (a)	20			23			16
	Deductions (b)	(116		)	(124		)	(195		)
	Balance at End of Period	$	54		$	55		$	62
	_______________________________________
	(a)	Collection of accounts previously written off.
	(b)	Uncollectible accounts written off.

Organization_and_Basis_of_Pres2

Organization and Basis of Presentation (Details Textuals) (USD $)	Dec. 31, 2014
	customers
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Number of electric utility customers	2,100,000
Number of gas utility customers	1,200,000
Significant potential exposure to loss due to VIE long-term purchase contracts	$0

Organization_and_Basis_of_Pres3

Organization and Basis of Presentation (Consolidated Variable Interest Entities) (Details) (USD $)	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
In Millions, unless otherwise specified
Assets [Abstract]
Cash and cash equivalents	$48	$52	$65	$68
Restricted cash	120	123
Accounts receivable	1,504	1,542
Property, plant and equipment, net	16,820	15,800
Securitized regulatory assets	34	231
Total Assets	27,974	25,935	26,339
Liabilities [Abstract]
Current portion long-term debt, including capital leases	274	898
Current regulatory liabilities	153	302
Mortgage bonds, notes and other	7,860	6,618
Securitization bonds	0	105
Capital lease obligations	3	11
Variable Interest Entity, Primary Beneficiary Securitization [Member]
Assets [Abstract]
Cash and cash equivalents	0	0
Restricted cash	96	100
Accounts receivable	26	34
Inventories	0	0
Property, plant and equipment, net	0	0
Securitized regulatory assets	34	231
Other current and long term assets	1	4
Total Assets	157	369
Liabilities [Abstract]
Accounts payable and accrued current liabilities	3	7
Current portion long-term debt, including capital leases	105	196
Current regulatory liabilities	32	43
Mortgage bonds, notes and other	0	0
Securitization bonds	0	105
Capital lease obligations	0	0
Other current and long term liabilities	9	8
Total Liabilities	149	359
Variable Interest Entity, Primary Beneficiary Other, Restricted [Member]
Assets [Abstract]
Cash and cash equivalents	7	12
Restricted cash	8	8
Accounts receivable	15	16
Inventories	67	118
Property, plant and equipment, net	81	99
Securitized regulatory assets	0	0
Other current and long term assets	6	9
Total Assets	184	262
Liabilities [Abstract]
Accounts payable and accrued current liabilities	8	23
Current portion long-term debt, including capital leases	10	9
Current regulatory liabilities	0	0
Mortgage bonds, notes and other	15	21
Securitization bonds	0	0
Capital lease obligations	3	7
Other current and long term liabilities	6	6
Total Liabilities	42	66
Variable Interest Entity, Primary Beneficiary, Restricted [Member]
Assets [Abstract]
Cash and cash equivalents	7	12
Restricted cash	104	108
Accounts receivable	41	50
Inventories	67	118
Property, plant and equipment, net	81	99
Securitized regulatory assets	34	231
Other current and long term assets	7	13
Total Assets	341	631
Liabilities [Abstract]
Accounts payable and accrued current liabilities	11	30
Current portion long-term debt, including capital leases	115	205
Current regulatory liabilities	32	43
Mortgage bonds, notes and other	15	21
Securitization bonds	0	105
Capital lease obligations	3	7
Other current and long term liabilities	15	14
Total Liabilities	$191	$425

Organization_and_Basis_of_Pres4

Organization and Basis of Presentation (Non Consolidated Variable Interest Entities) (Details) (USD $)	Dec. 31, 2014	Dec. 31, 2013
In Millions, unless otherwise specified
Variable Interest Entity [Line Items]
Notes receivable	$90	$102
Variable Interest Entity, NonConsolidated [Member]
Variable Interest Entity [Line Items]
Other investments	134	141
Notes receivable	$15	$8

Significant_Accounting_Policie3

Significant Accounting Policies Significant Accounting Policics (Accumulated Other Comprehensive Loss) (Details) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Beginning balance	($136)	($158)
Other comprehensive income (loss) before reclassifications	-26	13
Amounts reclassified from accumulated other comprehensive income	7	9
Other comprehensive income	-19	22	0
Ending balance	-155	-136	-158
Net Unrealized Gain/(Loss) on Derivatives [Member]
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Beginning balance	-4	-4
Other comprehensive income (loss) before reclassifications	0	0
Amounts reclassified from accumulated other comprehensive income	0	0
Other comprehensive income	0	0
Ending balance	-4	-4
Net Unrealized Gain/(Loss) on Investments [Member]
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Beginning balance	-6	-8
Other comprehensive income (loss) before reclassifications	1	2
Amounts reclassified from accumulated other comprehensive income	0	0
Other comprehensive income	1	2
Ending balance	-5	-6
Benefit Obligations [Member]
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Beginning balance	-126	-148
Other comprehensive income (loss) before reclassifications	-25	13
Amounts reclassified from accumulated other comprehensive income	7	9
Other comprehensive income	-18	22
Ending balance	-144	-126
Foreign Currency Translation [Member]
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Beginning balance	0	2
Other comprehensive income (loss) before reclassifications	-2	-2
Amounts reclassified from accumulated other comprehensive income	0	0
Other comprehensive income	-2	-2
Ending balance	($2)	$0

Significant_Accounting_Policie4

Significant Accounting Policies (Intangible Assets) (Details) (USD $)	Dec. 31, 2014	Dec. 31, 2013
In Millions, unless otherwise specified
Finite-Lived Intangible Assets [Line Items]
Intangible Assets, Gross (Excluding Goodwill)	$168	$179
Less: Accumulated Amortization	57	45
Intangible Assets, Net	111	134
Less current intangible assets	9	12
Intangible assets, noncurrent	102	122
Renewable Energy Credits [Member]
Finite-Lived Intangible Assets [Line Items]
Intangible Assets, Gross	45	51
Contract Intangible Assets [Member]
Finite-Lived Intangible Assets [Line Items]
Intangible Assets, Gross	122	126
Emission Allowances [Member]
Finite-Lived Intangible Assets [Line Items]
Indefinite-Lived Intangible Assets (Excluding Goodwill)	$1	$2

Significant_Accounting_Policie5

Significant Accounting Policies (Future Amortization Expense Intangible Assets) (Details) (USD $)	Dec. 31, 2014
In Millions, unless otherwise specified
Finite-Lived Intangible Assets, Net, Amortization Expense, Fiscal Year Maturity [Abstract]
2015	$12
2016	11
2017	8
2018	8
2019	$6

Significant_Accounting_Policie6

Significant Accounting Policies (Details Textuals) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Significant Accounting Policies [Line Items]
Other income	$196,000,000	$201,000,000	$173,000,000
Receivables due date	21 days
Threshold period past due for write-off of trade accounts receivable	150 days
Specific review of probable future collections based on receivable balances in excess of 90 days	30 days
Unbilled revenues	1,504,000,000	1,542,000,000
Regulatory liabilities	820,000,000	1,164,000,000
Property maintenance accrual period	18 months
Amortization of Intangible Assets	12,000,000	14,000,000	6,000,000
Excise and sales taxes net impact on statement of operations	0
Charitable Contributions to a Foundation	25,000,000	18,000,000	21,000,000
Refueling Outage [Member]
Significant Accounting Policies [Line Items]
Regulatory liabilities	16,000,000	26,000,000
Minimum [Member]
Significant Accounting Policies [Line Items]
Notes receivable considered delinquent period	60 days
Finite-lived intangible asset, useful life	1 year
Maximum
Significant Accounting Policies [Line Items]
Notes receivable considered delinquent period	120 days
Finite-lived intangible asset, useful life	27 years
Unbilled Revenues [Member]
Significant Accounting Policies [Line Items]
Unbilled revenues	773,000,000	815,000,000
Public Utilities, Inventory, Natural Gas [Member]
Significant Accounting Policies [Line Items]
LIFO inventory amount	43,000,000	4,000,000
Excess of replacement costs over stated LIFO value	110,000,000	170,000,000
Power and Industrial Projects [Member]
Significant Accounting Policies [Line Items]
Other income	$78,000,000	$81,000,000	$63,000,000

Discontinued_Operations_Detail

Discontinued Operations (Details Textuals) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Proceeds from divestiture of business	$0	$0	$255,000,000
Discontinued Operations [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Percentage of disposal of equity interest in segment percentage			100.00%
Proceeds from divestiture of business			255,000,000
Loss from disposal before tax			83,000,000
Loss from disposal, net of tax			55,000,000
Allocation of corporate interest costs			$0

Discontinued_Operations_Detail1

Discontinued Operations (Details) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Total operating expenses	$10,711	$8,458	$7,512
Income Tax Benefit	0	0	-29
Net Loss Attributable to DTE Energy Company	0	0	-56
Segment, Discontinued Operations [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Operating Revenues			55
Operation and maintenance			24
Depreciation, depletion and amortization			23
Taxes other than income			4
Asset (gains) losses, net			83
Total operating expenses			134
Operating Loss			-79
Other (Income) and Deductions			6
Loss Before Income Taxes			-85
Income Tax Benefit			-29
Net Loss Attributable to DTE Energy Company			($56)

Property_Plant_and_Equipment_S

Property, Plant and Equipment (Summary of Property by Classification) (Details) (USD $)	Dec. 31, 2014	Dec. 31, 2013
In Millions, unless otherwise specified
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment - Non-utility and other	$2,476	$2,292
Property, plant and equipment, Total	26,538	25,123
Less Accumulated Depreciation, Depletion and Amortization - Nonutility and Other	-867	-767
Accumulated Depreciation, Depletion and Amortization, Property, Plant, and Equipment	-9,718	-9,323
Property, plant and equipment	16,820	15,800
Electric Generation Equipment [Member]
Property, Plant and Equipment [Line Items]
Property Plant and Equipment - Generation	11,641	11,127
Accumulated Depreciation, Depletion and Amortization	-4,149	-4,004
Electric Distribution [Member]
Property, Plant and Equipment [Line Items]
Property Plant and Equipment - Distribution	8,164	7,603
Accumulated Depreciation, Depletion and Amortization	-3,067	-2,947
Electric Generation, Transmission and Distribution Equipment [Member]
Property, Plant and Equipment [Line Items]
Public Utilities, Property, Plant and Equipment, Plant in Service	19,805	18,730
Accumulated Depreciation, Depletion and Amortization	-7,216	-6,951
Gas Distribution [Member]
Property, Plant and Equipment [Line Items]
Property Plant and Equipment - Distribution	2,946	2,834
Accumulated Depreciation, Depletion and Amortization	-1,130	-1,129
Storage [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment - Storage	448	431
Accumulated Depreciation, Depletion and Amortization	-142	-138
Other [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment - Other	863	836
Accumulated Depreciation, Depletion and Amortization	-363	-338
Gas Distribution and Storage [Member]
Property, Plant and Equipment [Line Items]
Public Utilities, Property, Plant and Equipment, Plant in Service	4,257	4,101
Accumulated Depreciation, Depletion and Amortization	($1,635)	($1,605)

Property_Plant_and_Equipment_A

Property, Plant and Equipment (Average Estimated Useful Life of Each Major Class) (Details)	12 Months Ended
	Dec. 31, 2014
Electric [Member]
Public Utility Property, Plant and Equipment [Line Items]
Useful Life - Generation	40 years
Useful Life - Distribution	41 years
Gas [Member]
Public Utility Property, Plant and Equipment [Line Items]
Useful Life - Distribution	50 years
Useful Life - Storage	53 years

Property_Plant_and_Equipment_D

Property, Plant and Equipment (Details Textuals) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Public Utility Property, Plant and Equipment [Line Items]
AFUDC capitalized	$37	$33
Capitalized computer software amortization	77	71	68
Capitalized computer software gross	668	611
Capitalized computer software accumulated amortization	335	323
Capital leased assets gross	35	35
Capital leases, accumulated depreciation	$27	$21
Electric [Member]
Public Utility Property, Plant and Equipment [Line Items]
Disclosure of composite depreciation rate for plants in service	3.40%	3.40%	3.30%
Gas [Member]
Public Utility Property, Plant and Equipment [Line Items]
Disclosure of composite depreciation rate for plants in service	2.40%	2.40%	2.40%
Minimum [Member]
Public Utility Property, Plant and Equipment [Line Items]
Property plant and equipment, useful life	3 years
Finite-lived intangible asset, useful life	1 year
Maximum
Public Utility Property, Plant and Equipment [Line Items]
Property plant and equipment, useful life	55 years
Finite-lived intangible asset, useful life	27 years
Computer Software, Intangible Asset [Member] | Minimum [Member]
Public Utility Property, Plant and Equipment [Line Items]
Finite-lived intangible asset, useful life	3 years
Computer Software, Intangible Asset [Member] | Maximum
Public Utility Property, Plant and Equipment [Line Items]
Finite-lived intangible asset, useful life	15 years

Jointly_Owned_Utility_Plant_De

Jointly Owned Utility Plant (Details) (USD $)	Dec. 31, 2014
In Millions, unless otherwise specified	MW
Belle River [Member]
Jointly Owned Utility Plant Interests [Line Items]
Total plant capacity (in MW)	1,270
Investment (in millions)	$1,742
Accumulated depreciation (in millions)	993
Ludington Hydroelectric Pumped Storage [Member]
Jointly Owned Utility Plant Interests [Line Items]
Total plant capacity (in MW)	1,872
Ownership interest	49.00%
Investment (in millions)	412
Accumulated depreciation (in millions)	$175

Jointly_Owned_Utility_Plant_De1

Jointly Owned Utility Plant (Detail Textuals)	Dec. 31, 2014
	facilities
Jointly Owned Utility Plant Interests [Line Items]
Jointly Owned Utility Plant Number of Plants	2
Belle River Unit 1 [Member]
Jointly Owned Utility Plant Interests [Line Items]
Jointly Owned Utility Plant, Proportionate Ownership Share	63.00%
Belle River Facilities used jointly by Belle River and St. Clair Power Plants [Member]
Jointly Owned Utility Plant Interests [Line Items]
Jointly Owned Utility Plant, Proportionate Ownership Share	81.00%
Belle River [Member]
Jointly Owned Utility Plant Interests [Line Items]
Joint Owners Percentage of the Total Capacity Energy and Related Responsibilities	19.00%
Belle River Unit 2 [Member]
Jointly Owned Utility Plant Interests [Line Items]
Jointly Owned Utility Plant, Proportionate Ownership Share	75.00%
Ludington Hydroelectric Pumped Storage [Member]
Jointly Owned Utility Plant Interests [Line Items]
Jointly Owned Utility Plant, Proportionate Ownership Share	49.00%
Joint Owners Percentage of the Total Capacity Energy and Related Responsibilities	51.00%

Asset_Retirement_Obligations_D

Asset Retirement Obligations (Details) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2014
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]
Asset retirement obligations, beginning balance	$1,827
Accretion	112
Liabilities incurred	11
Liabilities settled	-12
Revision in estimated cash flows	24
Asset retirement obligations, ending balance	$1,962

Asset_Retirement_Obligations_D1

Asset Retirement Obligations (Details Textuals) (USD $)	12 Months Ended
	Dec. 31, 2014
Asset Retirement Obligations [Line Items]
Asset retirement obligations, liability not recognized	Natural gas storage system assets, substations, manholes and certain other distribution assets have an indeterminate life. Therefore, no liability has been recorded for these assets.
Liabilities balance upon completion of decommissioning	$0
Fermi 2 [Member]
Asset Retirement Obligations [Line Items]
Nuclear decommissioning liabilities funded through surcharge and included in ARO balance	$1,700,000,000

Regulatory_Matters_Schedule_of

Regulatory Matters (Schedule of Regulatory Assets) (Details) (USD $)	Dec. 31, 2014	Dec. 31, 2013
In Millions, unless otherwise specified
Regulatory Assets [Line Items]
Regulatory Assets	$3,727	$2,863
Regulatory Assets, Current	-76	-26
Regulatory Assets, Noncurrent	3,651	2,837
Securitized Regulatory Assets, Noncurrent	34	231
Pension Costs [Member]
Regulatory Assets [Line Items]
Regulatory Assets	2,284	1,660
Postretirment Costs [Member]
Regulatory Assets [Line Items]
Regulatory Assets	234	0
Asset Retirement Obligation Costs [Member]
Regulatory Assets [Line Items]
Regulatory Assets	448	394
Recoverable Michigan Income Taxes [Member]
Regulatory Assets [Line Items]
Regulatory Assets	267	286
Unamortized Loss on Reacquired Debt [Member]
Regulatory Assets [Line Items]
Regulatory Assets	67	63
Other Recoverabe Income Taxes [Member]
Regulatory Assets [Line Items]
Regulatory Assets	66	71
Accrued PSCR/GCR Revenue [Member]
Regulatory Assets [Line Items]
Regulatory Assets	61	0
Deferred Environmental Costs [Member]
Regulatory Assets [Line Items]
Regulatory Assets	59	59
Cost to Achieve Performance Excellence Process [Member]
Regulatory Assets [Line Items]
Regulatory Assets	54	75
Recoverable Income Taxes related to Securitized Regulatory Assets [Member]
Regulatory Assets [Line Items]
Regulatory Assets	19	126
Unrecovered Removal Costs [Member]
Regulatory Assets [Line Items]
Regulatory Assets	15	0
Transitional Recovery Mechanism [Member]
Regulatory Assets [Line Items]
Regulatory Assets	14	0
Other Assets [Member]
Regulatory Assets [Line Items]
Regulatory Assets	$139	$129

Regulatory_Matters_Regulatory_

Regulatory Matters Regulatory Matters (Schedule of Regulatory Liabilities) (Details) (USD $)	Dec. 31, 2014	Dec. 31, 2013
In Millions, unless otherwise specified
Regulatory Liabilities [Line Items]
Regulatory liabilities	$820	$1,164
Regulatory Liability, Current	-153	-302
Regulatory Liability, Noncurrent	667	862
Removal Costs [Member]
Regulatory Liabilities [Line Items]
Regulatory liabilities	308	351
Renewable Energy [Member]
Regulatory Liabilities [Line Items]
Regulatory liabilities	227	277
Over Recovery of Securitization [Member]
Regulatory Liabilities [Line Items]
Regulatory liabilities	71	72
Refundable Revenue Decoupling [Member]
Regulatory Liabilities [Line Items]
Regulatory liabilities	67	127
Pension Costs [Member]
Regulatory Liabilities [Line Items]
Regulatory liabilities	67	84
Refundable Income Taxes [Member]
Regulatory Liabilities [Line Items]
Regulatory liabilities	33	45
Energy Optimization [Member]
Regulatory Liabilities [Line Items]
Regulatory liabilities	24	31
Refueling Outage [Member]
Regulatory Liabilities [Line Items]
Regulatory liabilities	16	26
Refundable postretirement costs [Member]
Regulatory Liabilities [Line Items]
Regulatory liabilities	0	72
Accrued PSCR GCR Refund [Member]
Regulatory Liabilities [Line Items]
Regulatory liabilities	0	65
Other Liabilities [Member]
Regulatory Liabilities [Line Items]
Regulatory liabilities	$7	$14

Regulatory_Matters_Details_Tex

Regulatory Matters (Details Textuals) (USD $)	12 Months Ended	0 Months Ended	3 Months Ended
	Dec. 31, 2014	Dec. 19, 2014	Mar. 31, 2013	Dec. 31, 2013	Sep. 30, 2014	Jul. 30, 2012	Jan. 01, 2014	Sep. 30, 2012	Sep. 26, 2014	Aug. 31, 2013	Nov. 30, 2014
Regulatory Assets [Line Items]
Time period required by non-bypassable securitization bond surcharge to recover securitized regulatory asset	14 years
Amortization period of cost to achieve deferral	10 years
Deferral of investigation and remediation of costs associated with gas utilities former MGP sites	10 years
Regulatory liabilities	$820,000,000			$1,164,000,000
Refundable Revenue Decoupling [Member]
Regulatory Assets [Line Items]
Regulatory liabilities	67,000,000			127,000,000
Electric [Member]
Regulatory Assets [Line Items]
Fermi 2 production level of full capacity						68.00%
Maximum of challenged Fermi 2 outage charges					32,000,000
Electric [Member] | Refundable Revenue Decoupling [Member]
Regulatory Assets [Line Items]
Regulatory liabilities								127,000,000
Monthly amount to amortize from liability to income							10,600,000
MPSC [Member] | Electric [Member]
Regulatory Assets [Line Items]
Public utilities, requested rate increase (decrease)		370,000,000
Rate increase previously authorized by the MPSC challenged by Court of Appeals reopened by the MPSC										11,000,000
Approved recovery amount for customer 360									215,000,000
Approved amortization period for customer 360 recovery	15 years
PSCR under-recovery from 2 plan years prior			87,000,000
PSCR under-recovery from 3 plan years prior			148,000,000
MPSC [Member] | Gas [Member]
Regulatory Assets [Line Items]
Infrastructure recovery mechanism surcharge											$47,000,000

Income_Taxes_Reconciliation_of

Income Taxes (Reconciliation of Income Tax Expense to the Statutory Federal Income Tax Rate) (Details) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Effective Income Tax Rate Reconciliation, Amount [Abstract]
Income before income taxes	$1,275	$922	$960
Income tax expense at 35% statutory rate	446	323	336
Production tax credits	-119	-68	-49
Investment tax credits	-6	-6	-6
Depreciation	-4	-4	-4
AFUDC - Equity	-7	-5	-4
Employee Stock Ownership Plan dividends	-4	-4	-4
Domestic production activities deduction	0	-14	-14
State and local income taxes, net of federal benefit	51	37	37
Enactment of New York Corporate Income Tax Legislation, net of federal benefit	8	0	0
Other, net	-1	-5	-6
Income tax expense	$364	$254	$286
Effective income tax rate (as percent)	28.50%	27.50%	29.80%

Income_Taxes_Components_of_Inc

Income Taxes (Components of Income Tax Expense) (Details) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Current income tax expense (benefit)
Federal	($16)	$74	$190
State and other income tax	24	16	49
Total current income taxes	8	90	239
Deferred income tax expense
Federal	289	122	39
State and other income tax	67	42	8
Total deferred income taxes	356	164	47
Income tax expense	364	254	286
Discontinued operations	0	0	-29
Total	$364	$254	$257

Income_Taxes_Deferred_Tax_Asse

Income Taxes (Deferred Tax Assets (Liabilities)) (Details) (USD $)	Dec. 31, 2014	Dec. 31, 2013
In Millions, unless otherwise specified
Components of Deferred Tax Assets and Liabilities [Abstract]
Property, plant and equipment	($3,832)	($3,372)
Securitized regulatory assets	-2	-127
Tax credit carry-forwards	296	266
Pension and benefits	-152	-30
State net operating loss and credit carry-forwards	39	43
Deferred Tax Liabilities, Other	-19	-92
Deferred Tax Liabilities, Gross	-3,670	-3,312
Less valuation allowance	-31	-37
Current deferred income tax assets (liabilities)	75	-28
Long-term deferred income tax liabilities	-3,776	-3,321
Deferred income tax assets	861	934
Deferred income tax liabilities	-4,562	-4,283
Deferred income tax liabilities	($3,701)	($3,349)

Income_Taxes_Reconciliation_of1

Income Taxes (Reconciliation of Unrecognized Tax Benefits) (Details) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward]
Unrecognized Tax Benefits, beginning balance	$10	$11	$48
Reductions for tax positions of prior years	0	0	-2
Additions for tax positions of current year	0	0	1
Settlements	0	0	-30
Lapse of statute of limitations	-1	-1	-6
Unrecognized Tax Benefits, ending balance	$9	$10	$11

Income_Taxes_Details_Textuals

Income Taxes (Details Textuals) (USD $)	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2014	Dec. 31, 2013
Income Tax Disclosure [Abstract]
Deferred tax asset, general business tax credit carryforwards		$29,000,000
Deferred tax asset, alternative minimum tax credit carryforwards		267,000,000
Deferred tax assets, state net operating loss and credit carry-forwards		39,000,000	43,000,000
Valuation allowance		31,000,000	37,000,000
Unrecognized tax benefits that would impact effective tax rate		2,000,000	2,000,000
Significant change in unrecognized tax benefit is reasonable possible, amount of unrecorded benefit		6,000,000
Interest on income taxes accrued		1,000,000	1,000,000
Income tax penalties accrued		0
Interest on income taxes expense	($1,000,000)

Earnings_Per_Share_Details

Earnings Per Share (Details) (USD $)	3 Months Ended								12 Months Ended
In Millions, except Per Share data, unless otherwise specified	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 b common shares									475	453	413
Dividends declared b 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 b common shares									475	453	413
Dividends declared b 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

Fair_Value_Assets_and_Liabilit

Fair Value (Assets and Liabilities Recorded at Fair Value on a Recurring Basis) (Details) (USD $)	Dec. 31, 2014	Dec. 31, 2013
In Millions, unless otherwise specified
Assets [Abstract]
Nuclear decommissioning trusts	$1,241	$1,191
Derivative Asset [Abstract]
Derivative asset, gross	1,178	833
Derivative asset, Netting	-1,006	-707
Derivative assets, net	172	126
Liabilities [Abstract]
Total fair value of derivatives	-1,110	-936
Derivative liability, netting	1,025	698
Derivative Liabilities, net	-85	-238
Current Derivative Liability [Member]
Liabilities [Abstract]
Total fair value of derivatives	-1,041	-773
Noncurrent Derivative Liability [Member]
Liabilities [Abstract]
Total fair value of derivatives	-69	-163
Natural Gas Commodity Contract [Member]
Derivative Asset [Abstract]
Derivative asset, gross	787	396
Derivative asset, Netting	-681	-382
Derivative assets, net	106	14
Liabilities [Abstract]
Total fair value of derivatives	-718	-503
Derivative liability, netting	679	395
Derivative Liabilities, net	-39	-108
Electricity Commodity Contract [Member]
Derivative Asset [Abstract]
Derivative asset, gross	342	400
Derivative asset, Netting	-280	-291
Derivative assets, net	62	109
Liabilities [Abstract]
Total fair value of derivatives	-342	-398
Derivative liability, netting	298	269
Derivative Liabilities, net	-44	-129
Other Commodity Contract [Member]
Derivative Asset [Abstract]
Derivative asset, gross	45	37
Derivative asset, Netting	-42	-34
Derivative assets, net	3	3
Liabilities [Abstract]
Total fair value of derivatives	-45	-34
Derivative liability, netting	45	34
Derivative Liabilities, net	0	0
Other Derivative Contract [Member]
Derivative Asset [Abstract]
Derivative asset, gross	4	0
Derivative asset, Netting	-3	0
Derivative assets, net	1	0
Liabilities [Abstract]
Total fair value of derivatives	-5	-1
Derivative liability, netting	3	0
Derivative Liabilities, net	-2	-1
Recurring [Member]
Assets [Abstract]
Cash equivalents	112	125
Nuclear decommissioning trusts	1,241	1,191
Other Investments	150	136
Derivative Asset [Abstract]
Derivative asset, Netting	-1,006	-707
Derivative assets, net	172	126
Total assets	1,675	1,578
Liabilities [Abstract]
Derivative liability, netting	1,025	698
Derivative Liabilities, net	-85	-238
Net Assets (Liabilities) at the end of the period	1,590	1,340
Net Assets (Liabilities) at the end of the period, netting	19	-9
Recurring [Member] | Current Asset [Member]
Derivative Asset [Abstract]
Derivative asset, Netting	-955	-592
Total assets	240	224
Recurring [Member] | Non Current Asset [Member]
Derivative Asset [Abstract]
Derivative asset, Netting	-51	-115
Total assets	1,435	1,354
Recurring [Member] | Current Derivative Liability [Member]
Liabilities [Abstract]
Derivative liability, netting	964	578
Derivative Liabilities, net	-77	-195
Recurring [Member] | Noncurrent Derivative Liability [Member]
Liabilities [Abstract]
Derivative liability, netting	61	120
Derivative Liabilities, net	-8	-43
Recurring [Member] | Natural Gas Commodity Contract [Member]
Derivative Asset [Abstract]
Derivative asset, Netting	-681	-382
Derivative assets, net	106	14
Liabilities [Abstract]
Derivative liability, netting	679	395
Derivative Liabilities, net	-39	-108
Recurring [Member] | Electricity Commodity Contract [Member]
Derivative Asset [Abstract]
Derivative asset, Netting	-280	-291
Derivative assets, net	62	109
Liabilities [Abstract]
Derivative liability, netting	298	269
Derivative Liabilities, net	-44	-129
Recurring [Member] | Other Commodity Contract [Member]
Derivative Asset [Abstract]
Derivative asset, Netting	-42	-34
Derivative assets, net	3	3
Liabilities [Abstract]
Derivative liability, netting	45	34
Derivative Liabilities, net	0	0
Recurring [Member] | Other Derivative Contract [Member]
Derivative Asset [Abstract]
Derivative asset, Netting	-3	0
Derivative assets, net	1	0
Liabilities [Abstract]
Derivative liability, netting	3	0
Derivative Liabilities, net	-2	-1
Recurring [Member] | Level 1 [Member]
Assets [Abstract]
Cash equivalents	13	10
Nuclear decommissioning trusts	792	779
Other Investments	100	92
Derivative Asset [Abstract]
Derivative asset, gross	597	306
Total assets	1,502	1,187
Liabilities [Abstract]
Total fair value of derivatives	-610	-309
Net Assets (Liabilities) at the end of the period	892	878
Recurring [Member] | Level 1 [Member] | Current Asset [Member]
Derivative Asset [Abstract]
Total assets	582	277
Recurring [Member] | Level 1 [Member] | Non Current Asset [Member]
Derivative Asset [Abstract]
Total assets	920	910
Recurring [Member] | Level 1 [Member] | Current Derivative Liability [Member]
Liabilities [Abstract]
Total fair value of derivatives	-572	-268
Recurring [Member] | Level 1 [Member] | Noncurrent Derivative Liability [Member]
Liabilities [Abstract]
Total fair value of derivatives	-38	-41
Recurring [Member] | Level 1 [Member] | Natural Gas Commodity Contract [Member]
Derivative Asset [Abstract]
Derivative asset, gross	555	273
Liabilities [Abstract]
Total fair value of derivatives	-578	-277
Recurring [Member] | Level 1 [Member] | Electricity Commodity Contract [Member]
Derivative Asset [Abstract]
Derivative asset, gross	0	0
Liabilities [Abstract]
Total fair value of derivatives	0	0
Recurring [Member] | Level 1 [Member] | Other Commodity Contract [Member]
Derivative Asset [Abstract]
Derivative asset, gross	42	33
Liabilities [Abstract]
Total fair value of derivatives	-32	-32
Recurring [Member] | Level 1 [Member] | Other Derivative Contract [Member]
Derivative Asset [Abstract]
Derivative asset, gross	0	0
Liabilities [Abstract]
Total fair value of derivatives	0	0
Recurring [Member] | Level 2 [Member]
Assets [Abstract]
Cash equivalents	99	115
Nuclear decommissioning trusts	449	412
Other Investments	50	44
Derivative Asset [Abstract]
Derivative asset, gross	439	351
Total assets	1,037	922
Liabilities [Abstract]
Total fair value of derivatives	-382	-415
Net Assets (Liabilities) at the end of the period	655	507
Recurring [Member] | Level 2 [Member] | Current Asset [Member]
Derivative Asset [Abstract]
Total assets	504	400
Recurring [Member] | Level 2 [Member] | Non Current Asset [Member]
Derivative Asset [Abstract]
Total assets	533	522
Recurring [Member] | Level 2 [Member] | Current Derivative Liability [Member]
Liabilities [Abstract]
Total fair value of derivatives	-357	-328
Recurring [Member] | Level 2 [Member] | Noncurrent Derivative Liability [Member]
Liabilities [Abstract]
Total fair value of derivatives	-25	-87
Recurring [Member] | Level 2 [Member] | Natural Gas Commodity Contract [Member]
Derivative Asset [Abstract]
Derivative asset, gross	140	89
Liabilities [Abstract]
Total fair value of derivatives	-78	-140
Recurring [Member] | Level 2 [Member] | Electricity Commodity Contract [Member]
Derivative Asset [Abstract]
Derivative asset, gross	295	261
Liabilities [Abstract]
Total fair value of derivatives	-290	-272
Recurring [Member] | Level 2 [Member] | Other Commodity Contract [Member]
Derivative Asset [Abstract]
Derivative asset, gross	0	1
Liabilities [Abstract]
Total fair value of derivatives	-9	-2
Recurring [Member] | Level 2 [Member] | Other Derivative Contract [Member]
Derivative Asset [Abstract]
Derivative asset, gross	4	0
Liabilities [Abstract]
Total fair value of derivatives	-5	-1
Recurring [Member] | Level 3 [Member]
Assets [Abstract]
Cash equivalents	0	0
Nuclear decommissioning trusts	0	0
Other Investments	0	0
Derivative Asset [Abstract]
Derivative asset, gross	142	176
Total assets	142	176
Liabilities [Abstract]
Total fair value of derivatives	-118	-212
Net Assets (Liabilities) at the end of the period	24	-36
Recurring [Member] | Level 3 [Member] | Current Asset [Member]
Derivative Asset [Abstract]
Total assets	109	139
Recurring [Member] | Level 3 [Member] | Non Current Asset [Member]
Derivative Asset [Abstract]
Total assets	33	37
Recurring [Member] | Level 3 [Member] | Current Derivative Liability [Member]
Liabilities [Abstract]
Total fair value of derivatives	-112	-177
Recurring [Member] | Level 3 [Member] | Noncurrent Derivative Liability [Member]
Liabilities [Abstract]
Total fair value of derivatives	-6	-35
Recurring [Member] | Level 3 [Member] | Natural Gas Commodity Contract [Member]
Derivative Asset [Abstract]
Derivative asset, gross	92	34
Liabilities [Abstract]
Total fair value of derivatives	-62	-86
Recurring [Member] | Level 3 [Member] | Electricity Commodity Contract [Member]
Derivative Asset [Abstract]
Derivative asset, gross	47	139
Liabilities [Abstract]
Total fair value of derivatives	-52	-126
Recurring [Member] | Level 3 [Member] | Other Commodity Contract [Member]
Derivative Asset [Abstract]
Derivative asset, gross	3	3
Liabilities [Abstract]
Total fair value of derivatives	-4	0
Recurring [Member] | Level 3 [Member] | Other Derivative Contract [Member]
Derivative Asset [Abstract]
Derivative asset, gross	0	0
Liabilities [Abstract]
Total fair value of derivatives	$0	$0

Fair_Value_Reconciliation_of_L

Fair Value (Reconciliation of Level 3 Assets and Liabilities at Fair Value on a Recurring Basis) (Details) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Roll Forward]
Net Assets (Liabilities) as of December 31	($36,000,000)	($13,000,000)
Transfers into Level 3 from Level 2	0	1,000,000
Transfers from Level 3 into Level 2	-2,000,000	0
Total gains (losses):
Included in earnings	-20,000,000	43,000,000
Recorded in regulatory assets/liabilities	8,000,000	5,000,000
Purchases, issuances and settlements:
Purchases	1,000,000	-7,000,000
Issuances	-3,000,000	-1,000,000
Settlements	76,000,000	-64,000,000
Net Assets (Liabilities) as of December 31	24,000,000	-36,000,000
The amount of total gains (losses) included in net income attributed to the change in unrealized gains (losses) related to assets and liabilities held at December 31, 2014 and 2013 and reflected in Operating revenues and Fuel, purchased power and gas in the Consolidated Statements of Operations	40,000,000	-1,000,000
Natural Gas Commodity Contract [Member]
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Roll Forward]
Net Assets (Liabilities) as of December 31	-52,000,000	-38,000,000
Transfers into Level 3 from Level 2	0	1,000,000
Transfers from Level 3 into Level 2	-2,000,000	0
Total gains (losses):
Included in earnings	-40,000,000	-32,000,000
Recorded in regulatory assets/liabilities	0	0
Purchases, issuances and settlements:
Purchases	0	-8,000,000
Issuances	0	0
Settlements	124,000,000	25,000,000
Net Assets (Liabilities) as of December 31	30,000,000	-52,000,000
The amount of total gains (losses) included in net income attributed to the change in unrealized gains (losses) related to assets and liabilities held at December 31, 2014 and 2013 and reflected in Operating revenues and Fuel, purchased power and gas in the Consolidated Statements of Operations	35,000,000	-49,000,000
Electricity Commodity Contract [Member]
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Roll Forward]
Net Assets (Liabilities) as of December 31	13,000,000	23,000,000
Transfers into Level 3 from Level 2	0	0
Transfers from Level 3 into Level 2	0	0
Total gains (losses):
Included in earnings	25,000,000	75,000,000
Recorded in regulatory assets/liabilities	0	0
Purchases, issuances and settlements:
Purchases	1,000,000	1,000,000
Issuances	-3,000,000	-1,000,000
Settlements	-41,000,000	-85,000,000
Net Assets (Liabilities) as of December 31	-5,000,000	13,000,000
The amount of total gains (losses) included in net income attributed to the change in unrealized gains (losses) related to assets and liabilities held at December 31, 2014 and 2013 and reflected in Operating revenues and Fuel, purchased power and gas in the Consolidated Statements of Operations	9,000,000	48,000,000
Other Commodity Contract [Member]
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Roll Forward]
Net Assets (Liabilities) as of December 31	3,000,000	2,000,000
Transfers into Level 3 from Level 2	0	0
Transfers from Level 3 into Level 2	0	0
Total gains (losses):
Included in earnings	-5,000,000	0
Recorded in regulatory assets/liabilities	8,000,000	5,000,000
Purchases, issuances and settlements:
Purchases	0	0
Issuances	0	0
Settlements	-7,000,000	-4,000,000
Net Assets (Liabilities) as of December 31	-1,000,000	3,000,000
The amount of total gains (losses) included in net income attributed to the change in unrealized gains (losses) related to assets and liabilities held at December 31, 2014 and 2013 and reflected in Operating revenues and Fuel, purchased power and gas in the Consolidated Statements of Operations	($4,000,000)	$0

Fair_Value_Unobservable_Inputs

Fair Value (Unobservable Inputs related to Level 3 Assets and Liabilities) (Details) (USD $)	0 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Unobservable Input Valuation Techniques [Line Items]
Derivative asset, gross	$1,178	$833
Total fair value of derivatives	-1,110	-936
Natural Gas Commodity Contract [Member]
Unobservable Input Valuation Techniques [Line Items]
Derivative asset, gross	787	396
Total fair value of derivatives	-718	-503
Electricity Commodity Contract [Member]
Unobservable Input Valuation Techniques [Line Items]
Derivative asset, gross	342	400
Total fair value of derivatives	-342	-398
Level 3 [Member] | Discounted Cash Flow Valuation Technique [Member] | Natural Gas Commodity Contract [Member] | Minimum [Member]
Unobservable Input Valuation Techniques [Line Items]
Forward Basis Price	-2.28	-0.88
Level 3 [Member] | Discounted Cash Flow Valuation Technique [Member] | Natural Gas Commodity Contract [Member] | Maximum
Unobservable Input Valuation Techniques [Line Items]
Forward Basis Price	7.83	5.07
Level 3 [Member] | Discounted Cash Flow Valuation Technique [Member] | Natural Gas Commodity Contract [Member] | Weighted Average [Member]
Unobservable Input Valuation Techniques [Line Items]
Forward Basis Price	-0.22	-0.16
Level 3 [Member] | Discounted Cash Flow Valuation Technique [Member] | Electricity Commodity Contract [Member] | Minimum [Member]
Unobservable Input Valuation Techniques [Line Items]
Forward Basis Price	-14	-7
Level 3 [Member] | Discounted Cash Flow Valuation Technique [Member] | Electricity Commodity Contract [Member] | Maximum
Unobservable Input Valuation Techniques [Line Items]
Forward Basis Price	15	15
Level 3 [Member] | Discounted Cash Flow Valuation Technique [Member] | Electricity Commodity Contract [Member] | Weighted Average [Member]
Unobservable Input Valuation Techniques [Line Items]
Forward Basis Price	4	3
Recurring [Member] | Level 3 [Member]
Unobservable Input Valuation Techniques [Line Items]
Derivative asset, gross	142	176
Total fair value of derivatives	-118	-212
Recurring [Member] | Level 3 [Member] | Natural Gas Commodity Contract [Member]
Unobservable Input Valuation Techniques [Line Items]
Derivative asset, gross	92	34
Total fair value of derivatives	-62	-86
Recurring [Member] | Level 3 [Member] | Electricity Commodity Contract [Member]
Unobservable Input Valuation Techniques [Line Items]
Derivative asset, gross	47	139
Total fair value of derivatives	($52)	($126)

Fair_Value_Fair_Value_of_Finan

Fair Value (Fair Value of Financial Instruments) (Details) (USD $)	Dec. 31, 2014	Dec. 31, 2013
In Millions, unless otherwise specified
Reported Value Measurement [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Notes receivable, excluding capital leases	$41	$41
Dividends payable	122	116
Short-term borrowings	398	131
Long-term debt, excluding capital leases	8,606	8,094
Estimate of Fair Value Measurement [Member] | Level 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Notes receivable, excluding capital leases	0	0
Dividends payable	122	116
Short-term borrowings	0	0
Long-term debt, excluding capital leases	489	425
Estimate of Fair Value Measurement [Member] | Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Notes receivable, excluding capital leases	0	0
Dividends payable	0	0
Short-term borrowings	398	131
Long-term debt, excluding capital leases	8,308	7,551
Estimate of Fair Value Measurement [Member] | Level 3 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Notes receivable, excluding capital leases	41	41
Dividends payable	0	0
Short-term borrowings	0	0
Long-term debt, excluding capital leases	$706	$499

Fair_Value_Fair_Value_of_Nucle

Fair Value (Fair Value of Nuclear Decommissioning Trust Fund Assets) (Details) (USD $)	Dec. 31, 2014	Dec. 31, 2013
In Millions, unless otherwise specified
Schedule of Available-for-sale Securities [Line Items]
Decommissioning Fund Investments	$1,241	$1,191
Fermi 2 [Member]
Schedule of Available-for-sale Securities [Line Items]
Decommissioning Fund Investments	1,221	1,172
Fermi 1 [Member]
Schedule of Available-for-sale Securities [Line Items]
Decommissioning Fund Investments	3	3
Low Level Radioactive Waste [Member]
Schedule of Available-for-sale Securities [Line Items]
Decommissioning Fund Investments	17	16
Nuclear Decommissioning Trust Fund [Member]
Schedule of Available-for-sale Securities [Line Items]
Decommissioning Fund Investments	$1,241	$1,191

Fair_Value_Gains_and_Losses_an

Fair Value (Gains and Losses and Proceeds from the Sale of Securities by the Nuclear Decommissioning Trust Funds) (Details) (Nuclear Decommissioning Trust Fund [Member], USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Nuclear Decommissioning Trust Fund [Member]
Schedule of Available-for-sale Securities [Line Items]
Realized gains	$54	$83	$37
Realized losses	-33	-41	-31
Proceeds from sales of securities	$1,146	$1,118	$759

Fair_Value_Fair_Value_and_Unre

Fair Value (Fair Value and Unrealized Gains and Losses for the Nuclear Decommissioning Trust Funds) (Details) (USD $)	Dec. 31, 2014	Dec. 31, 2013
In Millions, unless otherwise specified
Schedule of Available-for-sale Securities [Line Items]
Nuclear decommissioning trusts	$1,241	$1,191
Gross Unrealized Gain	225	213
Gross Unrealized Loss	-41	-31
Nuclear Decommissioning Trust Fund [Member]
Schedule of Available-for-sale Securities [Line Items]
Equity Securities	756	730
Debt Securities	474	442
Cash equivalents	11	19
Equity Securities, Gross Unrealized Gain	204	201
Equity Securities, Gross Unrealized Loss	-39	-25
Debt Securities, Gross Unrealized Gain	21	12
Debt Securities, Gross Unrealized Loss	($2)	($6)

Fair_Value_Details_Textuals

Fair Value (Details Textuals) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Fair Value, Option, Quantitative Disclosures [Line Items]
Assets level 1 to level 2	$0	$0
Assets level 2 to 1	0	0
Liabilities level 1 to 2	0	0
Liabilities level 2 to 1	0	0
Unrealized losses on available for sale securities	-7,000,000	-9,000,000
Trading securities realized gain (loss)	14,000,000	22,000,000	11,000,000
Accumulated Net Unrealized Investment Gain (Loss) [Member]
Fair Value, Option, Quantitative Disclosures [Line Items]
Unrealized losses on available for sale securities	0	0
Nuclear Decommissioning Trust Fund [Member]
Fair Value, Option, Quantitative Disclosures [Line Items]
Cash equivalents	11,000,000	19,000,000
Average maturity of debt securities	7 years	7 years
Cash and Cash Equivalents [Member]
Fair Value, Option, Quantitative Disclosures [Line Items]
Nuclear decommissioning trust fund investments	1.00%	2.00%
Equity Securities [Member]
Fair Value, Option, Quantitative Disclosures [Line Items]
Nuclear decommissioning trust fund investments	61.00%	61.00%
Debt Securities [Member]
Fair Value, Option, Quantitative Disclosures [Line Items]
Nuclear decommissioning trust fund investments	38.00%	37.00%
Recurring [Member]
Fair Value, Option, Quantitative Disclosures [Line Items]
Cash equivalents	112,000,000	125,000,000
Restricted Assets [Member] | Recurring [Member]
Fair Value, Option, Quantitative Disclosures [Line Items]
Cash equivalents	105,000,000	109,000,000
Other Investments [Member] | Recurring [Member]
Fair Value, Option, Quantitative Disclosures [Line Items]
Cash equivalents	7,000,000	16,000,000
Other Investments [Member] | Recurring [Member] | Equity [Member]
Fair Value, Option, Quantitative Disclosures [Line Items]
Available-for-sale securities	8,000,000	7,000,000
Other investments	$150,000,000	$136,000,000

Financial_and_Other_Derivative2

Financial and Other Derivative Instruments (Fair Value of Derivative Instruments) (Details) (USD $)	Dec. 31, 2014	Dec. 31, 2013
In Millions, unless otherwise specified
Derivatives, Fair Value [Line Items]
Total fair value of derivatives	$1,178	$833
Total fair value of derivatives	-1,110	-936
Natural Gas Commodity Contract [Member]
Derivatives, Fair Value [Line Items]
Total fair value of derivatives	787	396
Total fair value of derivatives	-718	-503
Electricity Commodity Contract [Member]
Derivatives, Fair Value [Line Items]
Total fair value of derivatives	342	400
Total fair value of derivatives	-342	-398
Other Commodity Contract [Member]
Derivatives, Fair Value [Line Items]
Total fair value of derivatives	45	37
Total fair value of derivatives	-45	-34
Not Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Total fair value of derivatives	1,178	833
Total fair value of derivatives	-1,110	-936
Not Designated as Hedging Instrument [Member] | Foreign Currency Exchange Contract [Member]
Derivatives, Fair Value [Line Items]
Total fair value of derivatives	4	0
Total fair value of derivatives	-5	-1
Not Designated as Hedging Instrument [Member] | Natural Gas Commodity Contract [Member]
Derivatives, Fair Value [Line Items]
Total fair value of derivatives	787	396
Total fair value of derivatives	-718	-503
Not Designated as Hedging Instrument [Member] | Electricity Commodity Contract [Member]
Derivatives, Fair Value [Line Items]
Total fair value of derivatives	342	400
Total fair value of derivatives	-342	-398
Not Designated as Hedging Instrument [Member] | Other Commodity Contract [Member]
Derivatives, Fair Value [Line Items]
Total fair value of derivatives	45	37
Total fair value of derivatives	-45	-34
Current Derivative Asset [Member]
Derivatives, Fair Value [Line Items]
Total fair value of derivatives	1,083	691
Noncurrent Derivative Asset [Member]
Derivatives, Fair Value [Line Items]
Total fair value of derivatives	95	142
Current Derivative Liability [Member]
Derivatives, Fair Value [Line Items]
Total fair value of derivatives	-1,041	-773
Noncurrent Derivative Liability [Member]
Derivatives, Fair Value [Line Items]
Total fair value of derivatives	($69)	($163)

Financial_and_Other_Derivative3

Financial and Other Derivative Instruments (Netting Offsets of Derivative Assets and Liabilites) (Details) (USD $)	Dec. 31, 2014	Dec. 31, 2013
In Millions, unless otherwise specified
Offsetting Assets [Line Items]
Total fair value of derivatives	$1,178	$833
Derivative Asset, Fair Value, Gross Liability	-1,006	-707
Net Amounts of Assets Presented in the Statements of Financial Position	172	126
Fair Value Gross Amounts of Recognized (Liabilities)	-1,110	-936
Derivative Liability, Fair Value, Gross Asset	1,025	698
Net Amounts of (Liabilities) Presented in the Statements of Financial Position	-85	-238
Natural Gas Commodity Contract [Member]
Offsetting Assets [Line Items]
Total fair value of derivatives	787	396
Derivative Asset, Fair Value, Gross Liability	-681	-382
Net Amounts of Assets Presented in the Statements of Financial Position	106	14
Fair Value Gross Amounts of Recognized (Liabilities)	-718	-503
Derivative Liability, Fair Value, Gross Asset	679	395
Net Amounts of (Liabilities) Presented in the Statements of Financial Position	-39	-108
Electricity Commodity Contract [Member]
Offsetting Assets [Line Items]
Total fair value of derivatives	342	400
Derivative Asset, Fair Value, Gross Liability	-280	-291
Net Amounts of Assets Presented in the Statements of Financial Position	62	109
Fair Value Gross Amounts of Recognized (Liabilities)	-342	-398
Derivative Liability, Fair Value, Gross Asset	298	269
Net Amounts of (Liabilities) Presented in the Statements of Financial Position	-44	-129
Other Commodity Contract [Member]
Offsetting Assets [Line Items]
Total fair value of derivatives	45	37
Derivative Asset, Fair Value, Gross Liability	-42	-34
Net Amounts of Assets Presented in the Statements of Financial Position	3	3
Fair Value Gross Amounts of Recognized (Liabilities)	-45	-34
Derivative Liability, Fair Value, Gross Asset	45	34
Net Amounts of (Liabilities) Presented in the Statements of Financial Position	0	0
Other Derivative Contract [Member]
Offsetting Assets [Line Items]
Total fair value of derivatives	4	0
Derivative Asset, Fair Value, Gross Liability	-3	0
Net Amounts of Assets Presented in the Statements of Financial Position	1	0
Fair Value Gross Amounts of Recognized (Liabilities)	-5	-1
Derivative Liability, Fair Value, Gross Asset	3	0
Net Amounts of (Liabilities) Presented in the Statements of Financial Position	($2)	($1)

Financial_and_Other_Derivative4

Financial and Other Derivative Instruments (Netting Offsets Reconciliation to Balance Sheet) (Details) (USD $)	Dec. 31, 2014	Dec. 31, 2013
Derivative Assets:
Total fair value of derivatives	$1,178,000,000	$833,000,000
Collateral adjustment	0	-26,000,000
Derivative Asset, Current	128,000,000	99,000,000
Derivative Assets, Noncurrent	44,000,000	27,000,000
Derivative Liabilities:
Total fair value of derivatives	-1,110,000,000	-936,000,000
Counterparty netting	19,000,000	17,000,000
Derivative Liabilities, Current	-77,000,000	-195,000,000
Derivative Liabilities, Noncurrent	-8,000,000	-43,000,000
Current Derivative Asset [Member]
Derivative Assets:
Total fair value of derivatives	1,083,000,000	691,000,000
Counterparty netting	-955,000,000	-566,000,000
Collateral adjustment	0	-26,000,000
Noncurrent Derivative Asset [Member]
Derivative Assets:
Total fair value of derivatives	95,000,000	142,000,000
Counterparty netting	-51,000,000	-115,000,000
Collateral adjustment	0	0
Current Derivative Liability [Member]
Derivative Liabilities:
Total fair value of derivatives	-1,041,000,000	-773,000,000
Counterparty netting	9,000,000	12,000,000
Collateral adjustment	955,000,000	566,000,000
Noncurrent Derivative Liability [Member]
Derivative Liabilities:
Total fair value of derivatives	-69,000,000	-163,000,000
Counterparty netting	10,000,000	5,000,000
Collateral adjustment	$51,000,000	$115,000,000

Financial_and_Other_Derivative5

Financial and Other Derivative Instruments (Effect of Derivatives not Deisgnated as Hedging Instruments on the Consolidated Statement of Operations) (Details) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Derivative Instruments, Gain (Loss) [Line Items]
Derivative Instruments Not Designated as Hedging Instruments, Gain (Loss), Net	$79	($11)
Foreign Currency Exchange Contract [Member] | Operating Revenue [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative Instruments Not Designated as Hedging Instruments, Gain (Loss), Net	-2	-1
Natural Gas Commodity Contract [Member] | Operating Revenue [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative Instruments Not Designated as Hedging Instruments, Gain (Loss), Net	-30	-48
Natural Gas Commodity Contract [Member] | Fuel, purchased power and gas [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative Instruments Not Designated as Hedging Instruments, Gain (Loss), Net	-5	-44
Electricity Commodity Contract [Member] | Operating Revenue [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative Instruments Not Designated as Hedging Instruments, Gain (Loss), Net	123	82
Other Commodity Contract [Member] | Operating Revenue [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative Instruments Not Designated as Hedging Instruments, Gain (Loss), Net	($7)	$0

Financial_and_Other_Derivative6

Financial and Other Derivative Instruments (Cumulative Gross Volume of Derivative Contracts Outstanding) (Details) (CAD)	Dec. 31, 2014
	MMBTU
Natural Gas Commodity Contract [Member]
Derivative [Line Items]
Derivative outstanding, energy	895,599,953
Electricity Commodity Contract [Member]
Derivative [Line Items]
Derivative outstanding, energy	11,296,153
Foreign Currency Exchange Contract [Member]
Derivative [Line Items]
Foreign Currency Exchange (Canadian dollars)	63,022,462

Financial_and_Other_Derivative7

Financial and Other Derivative Instruments (Details Textuals) (USD $)	Dec. 31, 2014	Dec. 31, 2013
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Letters of credit that could be used to offset net derivative liabilities	$7,000,000	$19,000,000
Letters of credit received that could be used to offset net derivative assets	5,000,000	1,000,000
Cash collateral posted, net of cash collateral received	61,000,000	12,000,000
Derivative asset, counterparty netting	0	26,000,000
Derivative liability, counterparty netting	19,000,000	17,000,000
Cash collateral received	2,000,000	13,000,000
Cash collateral paid	44,000,000	34,000,000
Derivative net liability position aggregate fair value	1,058,000,000
Collateral already posted fair value	12,000,000
Derivative, net asset position, fair value	973,000,000
Remaining amount of offsets to derivative net liability positions for hard and soft trigger provisions	73,000,000
Additional collateral, aggregate fair value	$349,000,000

LongTerm_Debt_Long_Term_Debt_O

Long-Term Debt (Long Term Debt Outstanding and Weighted Average Interest Rates) (Details) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Debt Instrument [Line Items]
Long-term Debt, Total	$8,620
Long Term Debt excluding Securitization, Debentures and Capital Leases	8,021	7,312
Less Amount of Long-term Debt due within one year	-161	-694
Long-term Debt, Excluding Current Maturities	7,860	6,618
Less Amount of Securitization Bonds due within one year	-105	-197
Securitization bonds, Excluding Current Maturities	0	105
Junior Subordinated Notes, Noncurrent	480	480
6.6% Securitization Bonds Due 2015 [Member]
Debt Instrument [Line Items]
Debt, Weighted Average Interest Rate	6.60%
Debt Instrument, Maturity Date	15-Mar-15
Long-term Securitization Bond	105	302
Junior Subordinated Debentures [Member] | 6.5% Junior Subordinated Debentures Due 2061 [Member]
Debt Instrument [Line Items]
Debt, Weighted Average Interest Rate	6.50%
Debt Instrument, Maturity Date	1-Dec-61
Junior Subordinated Notes, Noncurrent	280	280
Junior Subordinated Debentures [Member] | 5.25% Junior Subordinated Debentures Due 2062 [Member]
Debt Instrument [Line Items]
Debt, Weighted Average Interest Rate	5.25%
Debt Instrument, Maturity Date	1-Dec-62
Junior Subordinated Notes, Noncurrent	200	200
DTE Energy [Member] | Unsecured Debt [Member] | 4.6% Unsecured Debt Due 2016 to 2033 [Member]
Debt Instrument [Line Items]
Debt, Weighted Average Interest Rate	4.60%
Debt Instrument, Maturity Date Range, Start	1-Jun-16
Debt Instrument, Maturity Date Range, End	15-Apr-33
Long-term Debt, Total	1,647	1,297
DTE Electric [Member] | Secured Debt [Member] | 4.5% Taxable Debt, Principally Secured Due 2016 to 2044 [Member]
Debt Instrument [Line Items]
Debt, Weighted Average Interest Rate	4.50%
Debt Instrument, Maturity Date Range, Start	31-Mar-16
Debt Instrument, Maturity Date Range, End	1-Jun-44
Long-term Debt, Total	4,824	4,286
DTE Electric [Member] | Tax Exempt Revenue Bonds [Member] | 5.2% Tax Exempt Revenue Bonds Due 2020 to 2030 [Member]
Debt Instrument [Line Items]
Debt, Weighted Average Interest Rate	5.20%
Debt Instrument, Maturity Date Range, Start	1-Jul-20
Debt Instrument, Maturity Date Range, End	1-Dec-30
Long-term Debt, Total	330	558
DTE Gas [Member] | Secured Debt [Member] | 5.2% Taxable Debt, Principally Secured Due 2015 to 2044 [Member]
Debt Instrument [Line Items]
Debt, Weighted Average Interest Rate	5.20%
Debt Instrument, Maturity Date Range, Start	1-Sep-15
Debt Instrument, Maturity Date Range, End	15-Dec-44
Long-term Debt, Total	1,099	1,029
DTE Gas [Member] | Long Term Debt, Other [Member]
Debt Instrument [Line Items]
Long-term Debt, Total	$121	$142

LongTerm_Debt_Debt_Issuances_D

Long-Term Debt (Debt Issuances) (Details) (USD $)	Dec. 31, 2014
In Millions, unless otherwise specified
Debt Instrument [Line Items]
Debt face amount	$1,750
DTE Energy [Member] | Senior Notes [Member] | May 2014 3.50% Senior Notes Maturing in 2024 [Member]
Debt Instrument [Line Items]
Debt instrument stated interest rate	3.50%
Debt face amount	350
DTE Energy [Member] | Senior Notes [Member] | November 2014 2.40% Senior Notes Maturing in 2019 [Member]
Debt Instrument [Line Items]
Debt instrument stated interest rate	2.40%
Debt face amount	300
Electric [Member] | Mortgages [Member] | June 2014 3.77% Mortgage Bonds Maturing in 2026 [Member]
Debt Instrument [Line Items]
Debt instrument stated interest rate	3.77%
Debt face amount	100
Electric [Member] | Mortgages [Member] | June 2014 4.60% Mortgage Bonds Maturing in 2044 [Member]
Debt Instrument [Line Items]
Debt instrument stated interest rate	4.60%
Debt face amount	150
Electric [Member] | Mortgages [Member] | July 2014 3.375% Mortgage Bonds Maturing in 2025 [Member]
Debt Instrument [Line Items]
Debt instrument stated interest rate	3.38%
Debt face amount	350
Electric [Member] | Mortgages [Member] | July 2014 4.30% Mortgage Bonds Maturing in 2044 [Member]
Debt Instrument [Line Items]
Debt instrument stated interest rate	4.30%
Debt face amount	350
Gas [Member] | Mortgages [Member] | December 2014 4.35% Mortgage Bonds Maturing in 2044 [Member]
Debt Instrument [Line Items]
Debt instrument stated interest rate	4.35%
Debt face amount	$150

LongTerm_Debt_Debt_Redemptions

Long-Term Debt (Debt Redemptions) (Details) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2014
Debt Instrument, Redemption [Line Items]
Extinguishment of debt	$1,237
Mortgages [Member] | Electric [Member] | March 2014 Mortgage Bonds Various Interest Rates Maturing in 2014 [Member]
Debt Instrument, Redemption [Line Items]
Extinguishment of debt	13
Mortgages [Member] | Gas [Member] | May 2014 Mortgage Bonds 8.25% Maturing in 2014 [Member]
Debt Instrument, Redemption [Line Items]
Debt instrument stated interest rate	8.25%
Extinguishment of debt	80
Senior Notes [Member] | Electric [Member] | July 2014 Senior Notes 4.80% Maturing in 2015 [Member]
Debt Instrument, Redemption [Line Items]
Debt instrument stated interest rate	4.80%
Extinguishment of debt	200
Senior Notes [Member] | Electric [Member] | August 2014 Senior Notes 5.40% Maturing in 2014 [Member]
Debt Instrument, Redemption [Line Items]
Debt instrument stated interest rate	5.40%
Extinguishment of debt	200
Senior Notes [Member] | DTE Energy [Member] | May 2014 Senior Notes 7.625% Maturing in 2014 [Member]
Debt Instrument, Redemption [Line Items]
Debt instrument stated interest rate	7.63%
Extinguishment of debt	300
Securitization Bonds [Member] | Electric [Member] | March 2014 Securitization Bonds 6.62% Maturing in 2014 [Member]
Debt Instrument, Redemption [Line Items]
Debt instrument stated interest rate	6.62%
Extinguishment of debt	100
Securitization Bonds [Member] | Electric [Member] | September 2014 Securitization Bonds 6.62% Maturing in 2014 [Member]
Debt Instrument, Redemption [Line Items]
Debt instrument stated interest rate	6.62%
Extinguishment of debt	96
Tax Exempt Revenue Bonds [Member] | Electric [Member] | April 2014 Tax Exempt Revenue Bonds 2.35% Maturing in 2024 [Member]
Debt Instrument, Redemption [Line Items]
Debt instrument stated interest rate	2.35%
Extinguishment of debt	31
Tax Exempt Revenue Bonds [Member] | Electric [Member] | April 2014 Tax Exempt Revenue Bonds 4.65% Maturing in 2028 [Member]
Debt Instrument, Redemption [Line Items]
Debt instrument stated interest rate	4.65%
Extinguishment of debt	32
Tax Exempt Revenue Bonds [Member] | Electric [Member] | June 2014 Tax Exempt Revenue Bonds 4.875% Maturing in 2029 [Member]
Debt Instrument, Redemption [Line Items]
Debt instrument stated interest rate	4.88%
Extinguishment of debt	36
Tax Exempt Revenue Bonds [Member] | Electric [Member] | June 2014 Tax Exempt Revenue Bonds 6.00% Maturing in 2036 [Member]
Debt Instrument, Redemption [Line Items]
Debt instrument stated interest rate	6.00%
Extinguishment of debt	69
Tax Exempt Revenue Bonds [Member] | Electric [Member] | August 2014 Tax Exempt Revenue Bonds 5.25% Maturing in 2029 [Member]
Debt Instrument, Redemption [Line Items]
Debt instrument stated interest rate	5.25%
Extinguishment of debt	60
Long Term Debt, Other [Member] | DTE Energy [Member]
Debt Instrument, Redemption [Line Items]
Extinguishment of debt	$20

LongTerm_Debt_Scheduled_Debt_M

Long-Term Debt (Scheduled Debt Maturities) (Details) (USD $)	Dec. 31, 2014
In Millions, unless otherwise specified
Maturities of Long-term Debt [Abstract]
2015	$266
2016	465
2017	9
2018	407
2019	427
2020 and Thereafter	7,046
Long-term Debt, Total	$8,620

LongTerm_Debt_Details_Textuals

Long-Term Debt (Details Textuals) (USD $)	Dec. 31, 2014	Dec. 31, 2013
In Millions, unless otherwise specified
Debt Instrument [Line Items]
Junior Subordinated Notes, Noncurrent	$480	$480

Preferred_and_Preferenced_Secu2

Preferred and Preferenced Securities (Details) (USD $)	Dec. 31, 2014
DTE Energy [Member]
Preferred and Preferenced Securities [Line Items]
Preferred stock, par value (in dollars per share)	$0
Preferred stock, shares authorized (in shares)	5,000,000
DTE Electric [Member]
Preferred and Preferenced Securities [Line Items]
Preferred stock, par value (in dollars per share)	$100
Preferred stock, shares authorized (in shares)	6,747,484
Preference stock, par value (in dollars per share)	$1
Preference stock shares authorized (in shares)	30,000,000
DTE Gas [Member]
Preferred and Preferenced Securities [Line Items]
Preferred stock, par value (in dollars per share)	$1
Preferred stock, shares authorized (in shares)	7,000,000
Preference stock, par value (in dollars per share)	$1
Preference stock shares authorized (in shares)	4,000,000

ShortTerm_Credit_Arrangements_2

Short-Term Credit Arrangements and Borrowings (Details) (USD $)	Dec. 31, 2014
Line Of Credit Facility [Line Items]
Line of Credit Facility, Maximum Borrowing Capacity	$2,025,000,000
Amounts outstanding	602,000,000
Net availability	1,423,000,000
DTE Energy [Member]
Line Of Credit Facility [Line Items]
Line of Credit Facility, Maximum Borrowing Capacity	1,425,000,000
Amounts outstanding	407,000,000
Net availability	1,018,000,000
DTE Electric [Member]
Line Of Credit Facility [Line Items]
Line of Credit Facility, Maximum Borrowing Capacity	300,000,000
Amounts outstanding	50,000,000
Net availability	250,000,000
DTE Gas [Member]
Line Of Credit Facility [Line Items]
Line of Credit Facility, Maximum Borrowing Capacity	300,000,000
Amounts outstanding	145,000,000
Net availability	155,000,000
Letter of Credit [Member]
Line Of Credit Facility [Line Items]
Amounts outstanding	204,000,000
Letter of Credit [Member] | DTE Energy [Member]
Line Of Credit Facility [Line Items]
Amounts outstanding	204,000,000
Letter of Credit [Member] | DTE Electric [Member]
Line Of Credit Facility [Line Items]
Amounts outstanding	0
Letter of Credit [Member] | DTE Gas [Member]
Line Of Credit Facility [Line Items]
Amounts outstanding	0
Letter of Credit [Member] | Unsecured letter of credit, expiring in February 2015 [Member]
Line Of Credit Facility [Line Items]
Line of Credit Facility, Maximum Borrowing Capacity	100,000,000
Letter of Credit [Member] | Unsecured letter of credit, expiring in February 2015 [Member] | DTE Energy [Member]
Line Of Credit Facility [Line Items]
Line of Credit Facility, Maximum Borrowing Capacity	100,000,000
Letter of Credit [Member] | Unsecured letter of credit, expiring in February 2015 [Member] | DTE Electric [Member]
Line Of Credit Facility [Line Items]
Line of Credit Facility, Maximum Borrowing Capacity	0
Letter of Credit [Member] | Unsecured letter of credit, expiring in February 2015 [Member] | DTE Gas [Member]
Line Of Credit Facility [Line Items]
Line of Credit Facility, Maximum Borrowing Capacity	0
Letter of Credit [Member] | Unsecured letter of credit, expiring in August 2015 [Member]
Line Of Credit Facility [Line Items]
Line of Credit Facility, Maximum Borrowing Capacity	125,000,000
Letter of Credit [Member] | Unsecured letter of credit, expiring in August 2015 [Member] | DTE Energy [Member]
Line Of Credit Facility [Line Items]
Line of Credit Facility, Maximum Borrowing Capacity	125,000,000
Letter of Credit [Member] | Unsecured letter of credit, expiring in August 2015 [Member] | DTE Electric [Member]
Line Of Credit Facility [Line Items]
Line of Credit Facility, Maximum Borrowing Capacity	0
Letter of Credit [Member] | Unsecured letter of credit, expiring in August 2015 [Member] | DTE Gas [Member]
Line Of Credit Facility [Line Items]
Line of Credit Facility, Maximum Borrowing Capacity	0
Revolving Credit Facility [Member] | Unsecured revolving credit facility, expiring April 2018 [Member]
Line Of Credit Facility [Line Items]
Line of Credit Facility, Maximum Borrowing Capacity	1,800,000,000
Revolving Credit Facility [Member] | Unsecured revolving credit facility, expiring April 2018 [Member] | DTE Energy [Member]
Line Of Credit Facility [Line Items]
Line of Credit Facility, Maximum Borrowing Capacity	1,200,000,000
Revolving Credit Facility [Member] | Unsecured revolving credit facility, expiring April 2018 [Member] | DTE Electric [Member]
Line Of Credit Facility [Line Items]
Line of Credit Facility, Maximum Borrowing Capacity	300,000,000
Revolving Credit Facility [Member] | Unsecured revolving credit facility, expiring April 2018 [Member] | DTE Gas [Member]
Line Of Credit Facility [Line Items]
Line of Credit Facility, Maximum Borrowing Capacity	300,000,000
Commercial Paper [Member]
Line Of Credit Facility [Line Items]
Amounts outstanding	398,000,000
Commercial Paper [Member] | DTE Energy [Member]
Line Of Credit Facility [Line Items]
Amounts outstanding	203,000,000
Commercial Paper [Member] | DTE Electric [Member]
Line Of Credit Facility [Line Items]
Amounts outstanding	50,000,000
Commercial Paper [Member] | DTE Gas [Member]
Line Of Credit Facility [Line Items]
Amounts outstanding	$145,000,000

ShortTerm_Credit_Arrangements_3

Short-Term Credit Arrangements and Borrowings (Details Textuals) (USD $)	Dec. 31, 2014	Dec. 31, 2013
Short-term Debt [Line Items]
Other outstanding letters of credit	$602,000,000
Short-term Debt, Weighted Average Interest Rate	0.40%	0.20%
Line of Credit Facility, Dividend Restrictions	730,000,000
Retained Earnings (Accumulated Deficit)	4,578,000,000	4,150,000,000
Other Restrictions on Payment of Dividends	0
DTE Energy [Member]
Short-term Debt [Line Items]
Total Funded Debt to Total Capitalization Ratio	0.5
Other outstanding letters of credit	407,000,000
DTE Electric [Member]
Short-term Debt [Line Items]
Total Funded Debt to Total Capitalization Ratio	0.51
Other outstanding letters of credit	50,000,000
DTE Gas [Member]
Short-term Debt [Line Items]
Total Funded Debt to Total Capitalization Ratio	0.48
Other outstanding letters of credit	145,000,000
Letter of Credit [Member]
Short-term Debt [Line Items]
Other outstanding letters of credit	204,000,000
Letter of Credit [Member] | DTE Energy [Member]
Short-term Debt [Line Items]
Other outstanding letters of credit	204,000,000
Letter of Credit [Member] | DTE Electric [Member]
Short-term Debt [Line Items]
Other outstanding letters of credit	0
Letter of Credit [Member] | DTE Gas [Member]
Short-term Debt [Line Items]
Other outstanding letters of credit	0
Demand Financing Agreement [Member] | DTE Energy [Member]
Short-term Debt [Line Items]
Financing Agreement, Maximum Borrowing Capacity	100,000,000
Maximum Additional Margin Financing	50,000,000
Financing Agreement, Amount Outstanding	37,000,000	138,000,000
Demand Financing Agreement Plus Letter of Credit [Member] | DTE Energy [Member]
Short-term Debt [Line Items]
Financing Agreement, Maximum Borrowing Capacity	150,000,000
Other outstanding letters of credit [Member] | Letter of Credit [Member] | DTE Energy [Member]
Short-term Debt [Line Items]
Other outstanding letters of credit	35,000,000
Demand Financing Agreement [Member] | Letter of Credit [Member] | DTE Energy [Member]
Short-term Debt [Line Items]
Financing Agreement, Maximum Borrowing Capacity	$50,000,000
Maximum
Short-term Debt [Line Items]
Total Funded Debt to Total Capitalization Ratio	0.65

Capital_and_Operating_Leases_F

Capital and Operating Leases (Future Minimum Lease Payments under Non-Cancelable Leases) (Details) (USD $)	Dec. 31, 2014
In Millions, unless otherwise specified
Operating Leases, Future Minimum Payments Due, Fiscal Year Maturity [Abstract]
2015	$42
2016	34
2017	28
2018	23
2019	14
Thereafter	78
Total minimum lease payments	$219

Capital_and_Operating_Componen

Capital and Operating (Components of the Net Investment in the Capital Leases) (Details) (USD $)	Dec. 31, 2014
In Millions, unless otherwise specified
Capital Leases of Lessor [Abstract]
2015	$12
2016	13
2017	13
2018	13
2019	10
Thereafter	9
Total minimum future lease receipts	70
Residual value of leased pipeline	40
Less unearned income	-34
Net investment in capital lease	76
Less current portion	-5
Capital Lease, noncurrent	$71

Capital_and_Operating_Leases_D

Capital and Operating Leases (Details Textuals) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Leases [Abstract]
Rent expense	$38	$34	$36
Pipeline System Lease [Member]
Schedule of Lessor Capital Leases [Line Items]
Lessor capital lease renewal terms	5 years
Percent ownership in pipeline	40.00%
Minimum [Member] | Energy Services Agreement [Member]
Schedule of Lessor Capital Leases [Line Items]
Lessor capital lease renewal terms	3 years
Maximum | Energy Services Agreement [Member]
Schedule of Lessor Capital Leases [Line Items]
Lessor capital lease renewal terms	5 years

Commitments_and_Contingencies_2

Commitments and Contingencies (Purchase Commitments) (Details) (USD $)	Dec. 31, 2014
In Millions, unless otherwise specified
Purchase Obligation, Fiscal Year Maturity [Abstract]
2015	$2,384
2016	1,258
2017	742
2018	477
2019	431
2020 and thereafter	3,723
Total Purchase Commitments	$9,015

Commitments_and_Contingencies_3

Commitments and Contingencies (Details Textuals) (USD $)	1 Months Ended	12 Months Ended	0 Months Ended	4 Months Ended	8 Months Ended
	Apr. 30, 2014	Dec. 31, 2014	31-May-14	15-May-14	Dec. 31, 2014	Dec. 31, 2010	Dec. 31, 2013
				kWh	kWh	dte_instances
					facilities
					dte_instances
Loss Contingencies [Line Items]
Number of NOVs						2
Possible Environmental Capital Expenditures to Comply with Requirements		$1,000,000
Estimated maximum spend to upgrade treatment technology to biological treatment to meet future requirements		13,000,000
Length of Notice of Intent to sue from the Group Against Smog and Pollution		60 days
Fine related to consent order and agreement with Allegheny County related to NOV	300,000
Estimated expenditures for a supplemental environmental project to enhance particulate collection efficiency		300,000
EPA Sulfur Dioxide Ambient Air Quality Standard		1 hour
Waiting Period of Policy		84 days
Total Purchase Commitments		9,015,000,000			9,015,000,000
Estimated future capital expenditures for next year		2,600,000,000			2,600,000,000
Gas [Member]
Loss Contingencies [Line Items]
Number of Former MGP Sites		15
Accrued for remediation related to the sites		24,000,000			24,000,000		28,000,000
Period Gas Utility Can Amortize MGP Costs		10 years
Electric [Member]
Loss Contingencies [Line Items]
Environmental Capital Expenditures Through Current Year		2,200,000,000
Estimated capital expenditures in next fiscal year		100,000,000
Environmental Capital Expenditures In Future Years		30,000,000
EPA is Alleging Power Plants Violated New Source Performance Standards		5			5
Number of NOVs/FOVs currently being discussed with the EPA		2			2
Time period to complete studies on cooling water intake structures impacts on fish - EPA ruling			3 years
Number of Former MGP Sites		3
Accrued for remediation related to the sites		10,000,000			10,000,000		8,000,000
Number of Permitted Engineered Ash Storage Facilities Owned		3
Insurance Coverage for Extra Expense when Power Plant Unavailable		490,000,000
Period of Coverage of Policy for Extra Expenses		3 years
Primary Coverage		1,500,000,000
Coverage for Stabilization Decontamination Debris Removal Repair and Replacement of Property and Decommissioning		1,250,000,000
Combined Coverage Limit for Total Property Damage		2,750,000,000
Insurance Deductible for Nuclear Power Plant		1,000,000			1,000,000
Total Limit for Property Damage for Non-Nuclear Events		2,000,000,000			2,000,000,000
Limit of Coverage for Aggregate Extra Expenses for Non-Nuclear Events		328,000,000
Limit for Property Damage for Non-Nuclear Events Aggregate of Extra Expenses of Period		2 years
Time Period for TRIA Insurance After the First Loss from Terrorism		1 year
NEIL Policies Against Terroism Loss		3,200,000,000
Amount per Event Loss Associated with Nuclear Power Plants		35,000,000
Maintenance of Public Liability Insurance for Nuclear Power Plants		375,000,000
Aggregate Limit of Liabilities Arises From Terroist Act Outside Scope of Trials Subject to One Industry		300,000,000
Deferred Premium Charged Leviied Against Each Licensed Nuclear Facility		127,000,000
Limit Deferred Premium Charges Per Year		19,000,000
Company Obligated to Pay DOE Fee of Fermi 2 Electricity Generated and Sold				1
Court of Appeals proposal to congress to reduce nuclear waste fee, amount					0
Synthetic Fuel [Member]
Loss Contingencies [Line Items]
Guarantor Obligations, Maximum Exposure, Undiscounted		1,000,000,000			1,000,000,000
Reduced Emissions Fuel Guarantees [Member]
Loss Contingencies [Line Items]
Guarantor Obligations, Maximum Exposure, Undiscounted		172,000,000			172,000,000
Guarantee Type, Other [Member]
Loss Contingencies [Line Items]
Guarantor Obligations, Maximum Exposure, Undiscounted		60,000,000			60,000,000
Surety Bond [Member]
Loss Contingencies [Line Items]
Performance Bonds Outstanding		$49,000,000			$49,000,000
Represented Employees [Member]
Loss Contingencies [Line Items]
Number of Represented Employees		4,900			4,900
Cleanup completed and site closed [Member] | Gas [Member]
Loss Contingencies [Line Items]
Number of Former MGP Sites		3
Partial closure expected by end of fiscal year [Member] | Gas [Member]
Loss Contingencies [Line Items]
Number of Former MGP Sites		2

Retirement_Benefits_and_Truste2

Retirement Benefits and Trusteed Assets (Pension Plan - Pension Cost Inclusions) (Details) (Pension Plan, USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Pension Plan
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]
Service cost	$83	$94	$82
Interest cost	212	192	204
Expected return on plan assets	-273	-266	-244
Amortization of Net Loss	157	208	176
Special termination benefits	0	0	2
Net pension cost	$179	$228	$220

Retirement_Benefits_and_Truste3

Retirement Benefits and Trusteed Assets (Pension Plan - Other Changes in Plan Assets and Benefit Obligations recognized in Reg Assets and OCI) (Details) (Pension Plan, USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Pension Plan
Other changes in plan assets and benefit obligations recognized in Regulatory assets and Other comprehensive income
Net actuarial (gain) loss	$805	($581)
Amortization of net actuarial loss	-157	-208
Prior service cost	-7	0
Total recognized Regulatory assets and Other comprehensive income	641	-789
Total recognized in net periodic pension cost, Regulatory assets and Other comprehensive income	820	-561
Estimated amounts to be amortized from Regulatory assets and Accumulated other comprehensive income into net periodic benefit cost during next fiscal year
Future amortization of net actuarial loss into net periodic benefit cost	$206	$151

Retirement_Benefits_and_Truste4

Retirement Benefits and Trusteed Assets (Pension Plan - Reconciliation of Obligations, Assets and Funded Status of Plans) (Details) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Amounts recognized in Regulatory assets (see Note 8)
Regulatory Assets	$3,727	$2,863
Pension Plan
Defined Benefit Plans and Other Postretirement Benefit Plans [Line Items]
Accumulated benefit obligation, end of year	4,853	4,068
Change in accumulated postretirement benefit obligation
Benefit obligation, beginning of year	4,380	4,729
Service cost	83	94	82
Interest cost	212	192	204
Plan amendments	-7	-3
Actuarial (gain) loss	836	-400
Benefits paid	-235	-232
Benefit obligation, end of year	5,269	4,380	4,729
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Plan assets at fair value, beginning of year	3,720	3,223
Actual return on plan assets	301	445
Company contributions	195	284
Benefits paid	-235	-232
Plan assets at fair value, end of year	3,981	3,720	3,223
Funded status of the plans	-1,288	-660
Amount recorded as:
Current liabilities	-8	-7
Noncurrent liabilities	-1,280	-653
Pension and Other Postretirement Defined Benefit Plans, Liabilities	-1,288	-660
Amounts recognized in Accumulated other comprehensive loss, pre-tax
Net actuarial loss	194	174
Prior service (credit)	-1	-1
Pension and Other Postretirement Benefit Plans, Accumulated Other Comprehensive Income (Loss), before Tax	193	173
Amounts recognized in Regulatory assets (see Note 8)
Net actuarial loss	2,285	1,654
Prior service credit	-1	6
Regulatory Assets	$2,284	$1,660

Retirement_Benefits_and_Truste5

Retirement Benefits and Trusteed Assets (Pension Plan - Benefits related to Qualified and Nonqualified Pension Plans Expected to be paid in the Next Ten Years) (Details) (Pension Plan, USD $)	Dec. 31, 2014
In Millions, unless otherwise specified
Pension Plan
Defined Benefit Plan, Expected Future Benefit Payments, Fiscal Year Maturity [Abstract]
2015	$269
2016	277
2017	286
2018	298
2019	309
2020-2024	1,634
Total Expected Future Benefit Payments	$3,073

Retirement_Benefits_and_Truste6

Retirement Benefits and Trusteed Assets (Pension Plan - Assumptions used in Determining the PBO and Net Pension Costs) (Details) (Pension Plan)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Pension Plan
Projected benefit obligation
Discount rate	4.12%	4.95%	4.15%
Rate of compensation increase	4.65%	4.20%	4.20%
Net pension costs
Discount rate	4.95%	4.15%	5.00%
Rate of compensation increase	4.20%	4.20%	4.20%
Expected long-term rate of return on plan assets	7.75%	8.25%	8.25%

Retirement_Benefits_and_Truste7

Retirement Benefits and Trusteed Assets (Pension Plan - Target Allocations of Plan Assets) (Details) (Pension Plan)	12 Months Ended
	Dec. 31, 2014
Defined Benefit Plan Disclosure [Line Items]
Target Allocation Percentage of Assets	100.00%
US Large Cap Equity Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Target Allocation Percentage of Assets	22.00%
US Small Cap and Mid Cap Equity Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Target Allocation Percentage of Assets	5.00%
Non US Equity Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Target Allocation Percentage of Assets	20.00%
Fixed Income Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Target Allocation Percentage of Assets	25.00%
Hedge Funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Target Allocation Percentage of Assets	20.00%
Private Equity Funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Target Allocation Percentage of Assets	8.00%

Retirement_Benefits_and_Truste8

Retirement Benefits and Trusteed Assets (Pension Plan - Fair Value Measurements) (Details) (Pension Plan, USD $)	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
In Millions, unless otherwise specified
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	$3,981	$3,720	$3,223
Short-term Investments [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	46	22
US Large Cap Equity Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	899	896
US Small Cap and Mid Cap Equity Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	225	221
Non US Equity Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	745	741
Fixed Income Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	1,120	937
Hedge Funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	759	733
Private Equity Funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	187	170
Securities Lending [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	-239	0
Securities Lending Collateral [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	239	0
Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	1,929	2,034
Level 1 [Member] | Short-term Investments [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	46	22
Level 1 [Member] | US Large Cap Equity Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	899	896
Level 1 [Member] | US Small Cap and Mid Cap Equity Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	225	221
Level 1 [Member] | Non US Equity Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	526	611
Level 1 [Member] | Fixed Income Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	7	16
Level 1 [Member] | Hedge Funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	226	268
Level 1 [Member] | Private Equity Funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	0	0
Level 1 [Member] | Securities Lending [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	-189	0
Level 1 [Member] | Securities Lending Collateral [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	189	0
Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	1,427	1,121
Level 2 [Member] | Short-term Investments [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	0	0
Level 2 [Member] | US Large Cap Equity Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	0	0
Level 2 [Member] | US Small Cap and Mid Cap Equity Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	0	0
Level 2 [Member] | Non US Equity Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	219	130
Level 2 [Member] | Fixed Income Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	1,113	921
Level 2 [Member] | Hedge Funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	95	70
Level 2 [Member] | Private Equity Funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	0	0
Level 2 [Member] | Securities Lending [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	-50	0
Level 2 [Member] | Securities Lending Collateral [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	50	0
Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	625	565	518
Level 3 [Member] | Short-term Investments [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	0	0
Level 3 [Member] | US Large Cap Equity Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	0	0
Level 3 [Member] | US Small Cap and Mid Cap Equity Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	0	0
Level 3 [Member] | Non US Equity Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	0	0
Level 3 [Member] | Fixed Income Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	0	0
Level 3 [Member] | Hedge Funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	438	395	339
Level 3 [Member] | Private Equity Funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	187	170	179
Level 3 [Member] | Securities Lending [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	0	0
Level 3 [Member] | Securities Lending Collateral [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	$0	$0

Retirement_Benefits_and_Truste9

Retirement Benefits and Trusteed Assets (Pension Plan - Fair Value Measurement using Level 3 Inputs) (Details) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
The amount of total gains (losses) included in net income attributed to the change in unrealized gains (losses) related to assets and liabilities held at December 31, 2014 and 2013 and reflected in Operating revenues and Fuel, purchased power and gas in the Consolidated Statements of Operations	$40	($1)
Pension Plan
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Plan assets at fair value, beginning of year	3,720	3,223
Total realized/unrealized gains (losses)	301	445
Plan assets at fair value, end of year	3,981	3,720
Pension Plan | Level 3 [Member]
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Plan assets at fair value, beginning of year	565	518
Total realized/unrealized gains (losses)	38	44
Purchases	53	31
Sales	-31	-28
Plan assets at fair value, end of year	625	565
The amount of total gains (losses) included in net income attributed to the change in unrealized gains (losses) related to assets and liabilities held at December 31, 2014 and 2013 and reflected in Operating revenues and Fuel, purchased power and gas in the Consolidated Statements of Operations	32	41
Pension Plan | Hedge Funds [Member]
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Plan assets at fair value, end of year	759	733
Pension Plan | Hedge Funds [Member] | Level 3 [Member]
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Plan assets at fair value, beginning of year	395	339
Total realized/unrealized gains (losses)	22	40
Purchases	22	16
Sales	-1	0
Plan assets at fair value, end of year	438	395
The amount of total gains (losses) included in net income attributed to the change in unrealized gains (losses) related to assets and liabilities held at December 31, 2014 and 2013 and reflected in Operating revenues and Fuel, purchased power and gas in the Consolidated Statements of Operations	21	38
Pension Plan | Private Equity Funds [Member]
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Plan assets at fair value, end of year	187	170
Pension Plan | Private Equity Funds [Member] | Level 3 [Member]
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Plan assets at fair value, beginning of year	170	179
Total realized/unrealized gains (losses)	16	4
Purchases	31	15
Sales	-30	-28
Plan assets at fair value, end of year	187	170
The amount of total gains (losses) included in net income attributed to the change in unrealized gains (losses) related to assets and liabilities held at December 31, 2014 and 2013 and reflected in Operating revenues and Fuel, purchased power and gas in the Consolidated Statements of Operations	$11	$3

Recovered_Sheet1

Retirement Benefits and Trusteed Assets (OPEB - Postretirement Cost Inclusions) (Details) (Other Postretirement Benefit Plan, USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Other Postretirement Benefit Plan
Defined Benefit Plan Disclosure [Line Items]
Service cost	$34	$47	$68
Interest cost	89	88	120
Expected return on plan assets	-122	-110	-92
Amortization of Net Loss	20	64	80
Amortization of Prior Service Cost (Credit)	-144	-131	-25
Net pension cost	($123)	($42)	$151

Recovered_Sheet2

Retirement Benefits and Trusteed Assets (OPEB - Other Changes in Plan Assets and APBO Recognized in Regulatory Assets and OCI) (Details) (Other Postretirement Benefit Plan, USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Other Postretirement Benefit Plan
Defined Benefit Plan Disclosure [Line Items]
Net actuarial (gain) loss	$192	($353)
Amortization of net actuarial loss	-20	-64
Prior service credit	0	-218
Amortization of prior service credit	144	131
Total recognized Regulatory assets and Other comprehensive income	316	-504
Total recognized in net periodic pension cost, Regulatory assets and Other comprehensive income	193	-546
Future amortization of net actuarial loss into net periodic benefit cost	43	21
Future amortization of prior service credit into net periodic benefit cost	($126)	($144)

Recovered_Sheet3

Retirement Benefits and Trusteed Assets (OPEB - Reconciliation of Obligations, Assets and Funded Status of Plans) (Details) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Amounts recognized in Regulatory assets (liabilities) (see Note 8)
Regulatory Liabilities	($820)	($1,164)
Other Postretirement Benefit Plan
Change in accumulated postretirement benefit obligation
Benefit obligation, beginning of year	1,878	2,315
Service cost	34	47	68
Interest cost	89	88	120
Plan amendments	0	-218
Actuarial (gain) loss	131	-267
Medicare Part D subsidy	0	1
Benefits paid	-88	-88
Benefit obligation, end of year	2,044	1,878	2,315
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Defined Benefit Plan, Fair Value of Plan Assets	1,528	1,527	1,153
Actual return on plan assets	62	196
Company contributions	24	264
Benefits paid	-85	-86
Funded status of the plans	-516	-351
Amount recorded as:
Current liabilities	-1	-1
Noncurrent liabilities	-515	-350
Pension and Other Postretirement Defined Benefit Plans, Liabilities	-516	-351
Amounts recognized in Accumulated other comprehensive loss, pre-tax
Net actuarial loss	34	29
Prior service (credit)	-5	-10
Pension and Other Postretirement Benefit Plans, Accumulated Other Comprehensive Income (Loss), before Tax	29	19
Amounts recognized in Regulatory assets (liabilities) (see Note 8)
Net actuarial loss	488	321
Prior service credit	-254	-393
Regulatory Liabilities	$234	($72)

Recovered_Sheet4

Retirement Benefits and Trusteed Assets (OPEB - Benefits related to Qualified and Nonqualified Pension Plans Expected to be paid in the Next Ten Years) (Details) (Other Postretirement Benefit Plan, USD $)	Dec. 31, 2014
In Millions, unless otherwise specified
Other Postretirement Benefit Plan
Defined Benefit Plan Disclosure [Line Items]
2015	$101
2016	107
2017	111
2018	117
2019	122
2020-2024	660
Total Expected Future Benefit Payments	$1,218

Recovered_Sheet5

Retirement Benefits and Trusteed Assets (OPEB - Assumptions used in Determining the PBO and Net Pension Costs) (Details)	3 Months Ended	9 Months Ended	12 Months Ended
	Mar. 31, 2013	Dec. 31, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Defined Benefit Plan Disclosure [Line Items]
Ultimate health care trend rate					5.00%
Health care trend rate pre- and post- 65					7.00%
Other Postretirement Benefit Plan
Defined Benefit Plan Disclosure [Line Items]
Discount rate	4.30%	4.95%	4.10%	4.95%	4.15%
Health care trend rate pre 65			7.50%	7.50%
Health care trend post 65			6.50%	6.50%
Ultimate health care trend rate			4.50%	4.50%
Health care trend pre 65			2025	2025
Health care trend post 65			6.50%
Year in which ultimate reached pre- and post- 65					2021
Ultimate year post 65			2024	2024
Other postretirement benefit costs, Discount Rate	4.15%	4.30%	4.95%		5.00%
Expected long-term rate of return on plan assets			8.00%	8.25%	8.25%
Health care trend rate pre-65			7.50%
Health care trend rate pre- and post- 65				7.00%	7.00%
Other Postretirement Benefit Plan | Other postretirement benefit costs [Member]
Defined Benefit Plan Disclosure [Line Items]
Ultimate health care trend rate			4.50%	5.00%	5.00%
Health care trend pre 65			2025
Year in which ultimate reached pre- and post- 65		2021		2021	2020
Ultimate year post 65			2024

Recovered_Sheet6

Retirement Benefits and Trusteed Assets (OPEB - Target Allocations of Plan Assets) (Details) (Other Postretirement Benefit Plan)	12 Months Ended
	Dec. 31, 2014
Defined Benefit Plan Disclosure [Line Items]
Target Allocation Percentage of Assets	100.00%
US Large Cap Equity Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Target Allocation Percentage of Assets	17.00%
US Small Cap and Mid Cap Equity Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Target Allocation Percentage of Assets	4.00%
Non US Equity Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Target Allocation Percentage of Assets	20.00%
Fixed Income Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Target Allocation Percentage of Assets	25.00%
Hedge Funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Target Allocation Percentage of Assets	20.00%
Private Equity Funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Target Allocation Percentage of Assets	14.00%

Recovered_Sheet7

Retirement Benefits and Trusteed Assets (OPEB - Fair Value Measurements) (Details) (Other Postretirement Benefit Plan, USD $)	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
In Millions, unless otherwise specified
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	$1,528	$1,527	$1,153
Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	765	883
Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	464	384
Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	299	260	205
Short-term Investments [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	6	5
Short-term Investments [Member] | Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	6	5
Short-term Investments [Member] | Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	0	0
Short-term Investments [Member] | Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	0	0
US Large Cap Equity Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	266	302
US Large Cap Equity Securities [Member] | Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	266	302
US Large Cap Equity Securities [Member] | Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	0	0
US Large Cap Equity Securities [Member] | Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	0	0
US Small Cap and Mid Cap Equity Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	149	147
US Small Cap and Mid Cap Equity Securities [Member] | Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	149	147
US Small Cap and Mid Cap Equity Securities [Member] | Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	0	0
US Small Cap and Mid Cap Equity Securities [Member] | Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	0	0
Non US Equity Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	281	291
Non US Equity Securities [Member] | Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	222	282
Non US Equity Securities [Member] | Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	59	9
Non US Equity Securities [Member] | Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	0	0
Fixed Income Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	375	367
Fixed Income Securities [Member] | Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	15	17
Fixed Income Securities [Member] | Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	360	350
Fixed Income Securities [Member] | Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	0	0
Hedge Funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	320	314
Hedge Funds [Member] | Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	107	130
Hedge Funds [Member] | Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	45	25
Hedge Funds [Member] | Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	168	159	119
Private Equity Funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	131	101
Private Equity Funds [Member] | Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	0	0
Private Equity Funds [Member] | Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	0	0
Private Equity Funds [Member] | Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	131	101	86
Securities Lending [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	-158	0
Securities Lending [Member] | Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	-141	0
Securities Lending [Member] | Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	-17	0
Securities Lending [Member] | Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	0	0
Securities Lending Collateral [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	158	0
Securities Lending Collateral [Member] | Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	141	0
Securities Lending Collateral [Member] | Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	17	0
Securities Lending Collateral [Member] | Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	$0	$0

Recovered_Sheet8

Retirement Benefits and Trusteed Assets (OPEB - Fair Value Measurements using Level 3 Inputs) (Details) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
The amount of total gains (losses) included in net income attributed to the change in unrealized gains (losses) related to assets and liabilities held at December 31, 2014 and 2013 and reflected in Operating revenues and Fuel, purchased power and gas in the Consolidated Statements of Operations	$40	($1)
Other Postretirement Benefit Plan
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Plan assets at fair value, beginning of year	1,527	1,153
Total realized/unrealized gains (losses)	62	196
Plan assets at fair value, end of year	1,528	1,527
Other Postretirement Benefit Plan | Hedge Funds [Member]
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Plan assets at fair value, end of year	320	314
Other Postretirement Benefit Plan | Private Equity Funds [Member]
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Plan assets at fair value, end of year	131	101
Level 3 [Member] | Other Postretirement Benefit Plan
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Plan assets at fair value, beginning of year	260	205
Total realized/unrealized gains (losses)	17	23
Purchases	42	41
Sales	-20	-9
Plan assets at fair value, end of year	299	260
The amount of total gains (losses) included in net income attributed to the change in unrealized gains (losses) related to assets and liabilities held at December 31, 2014 and 2013 and reflected in Operating revenues and Fuel, purchased power and gas in the Consolidated Statements of Operations	15	23
Level 3 [Member] | Other Postretirement Benefit Plan | Hedge Funds [Member]
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Plan assets at fair value, beginning of year	159	119
Total realized/unrealized gains (losses)	8	14
Purchases	9	26
Sales	-8	0
Plan assets at fair value, end of year	168	159
The amount of total gains (losses) included in net income attributed to the change in unrealized gains (losses) related to assets and liabilities held at December 31, 2014 and 2013 and reflected in Operating revenues and Fuel, purchased power and gas in the Consolidated Statements of Operations	7	14
Level 3 [Member] | Other Postretirement Benefit Plan | Private Equity Funds [Member]
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Plan assets at fair value, beginning of year	101	86
Total realized/unrealized gains (losses)	9	9
Purchases	33	15
Sales	-12	-9
Plan assets at fair value, end of year	131	101
The amount of total gains (losses) included in net income attributed to the change in unrealized gains (losses) related to assets and liabilities held at December 31, 2014 and 2013 and reflected in Operating revenues and Fuel, purchased power and gas in the Consolidated Statements of Operations	$8	$9

Recovered_Sheet9

Retirement Benefits and Trusteed Assets (Details Textuals) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Mar. 31, 2013
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Transfers into Level 3	$0	$1,000,000
Transfers out of Level 3	2,000,000	0
Defined contribution plan, cost recognized (less than $1 million in 2012)	48,000,000	41,000,000	37,000,000
Grantor Trust Balance	18,000,000	17,000,000
Retirement Savings Plan [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Company contribution to employee savings plan	4.00%
Retirement Savings Plan [Member] | DTE Gas Represented Employees
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Company contribution to employee savings plan	8.00%
Qualified Pension Plan [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Company contributions	188,000,000
Pension Plan
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Company contributions	195,000,000	284,000,000
Expected return on plan assets	7.75%
Transfers into Level 3	0	0
Transfers out of Level 3	0	0
Defined Benefit Plan, Assumptions Used Calculating Benefit Obligation, Discount Rate	4.12%	4.95%	4.15%
Pension Plan | Maximum
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Estimated future employer contributions in next fiscal year	180,000,000
Other Postretirement Benefit Plan
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Company contributions	24,000,000	264,000,000
Expected return on plan assets	8.00%
Transfers into Level 3	0	0
Transfers out of Level 3	0	0
Annual allocation to Retiree Reimbursement Account Per Participant, Retired on or before January 1, 2013	3,570	3,500
Annual allocation to Retiree Reimbursement Account Per Participant, Retired after January 1, 2013	3,315	3,250
Retiree Health Care Allowance will increase at lower of the rate of medical inflation or a set percentage	2.00%
Defined Benefit Plan, Effect of One Percentage Point Increase on Service and Interest Cost Components	8,000,000
Defined Benefit Plan, Effect of One Percentage Point Increase on Accumulated Postretirement Benefit Obligation	108,000,000
Defined Benefit Plan, Effect of One Percentage Point Decrease on Service and Interest Cost Components	7,000,000
Defined Benefit Plan, Effect of One Percentage Point Decrease on Accumulated Postretirement Benefit Obligation	94,000,000
Defined Benefit Plan, Assumptions Used Calculating Benefit Obligation, Discount Rate	4.10%	4.95%	4.15%	4.30%
Other Postretirement Benefit Plan | Maximum
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Estimated future employer contributions in next fiscal year	200,000,000
Retiree Healthcare Plan [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined contribution plan, cost recognized (less than $1 million in 2012)	$4,000,000	$2,000,000	$1,000,000

StockBased_Compensation_Compon

Stock-Based Compensation (Components of Stock Based Compensation) (Details) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Components of stock based-compensation [Abstract]
Compensation expense	$103	$99	$83
Employee Service Share-based Compensation Equity and Liability, Tax	40	38	33
Employee Service Share-based Compensation, Allocation of Recognized Period Costs Liability and Equity, Capitalized Amount	$16	$15	$5

StockBased_Compensation_Stock_

Stock-Based Compensation (Stock Option Activity) (Details) (USD $)	12 Months Ended
In Millions, except Share data, unless otherwise specified	Dec. 31, 2014
Number of options (in shares):
Options outstanding beginning of the year	723,697
Granted	0
Exercised	-268,689
Forfeited or expired	-10,730
Options outstanding end of the year	444,278
Weighted Average Exercise Price (in dollars per share):
Options outstanding beginning of the year	$42.60
Granted	$0
Exercised	$41.14
Forfeited or expired	$39.41
Options outstanding end of the year	$43.56
Outstanding, Intrinsic Value	$17

StockBased_Compensation_Number

Stock-Based Compensation (Number, Weighted Average Exercise Price and Weighted Average Remaining Contractual Life of Options Outstanding) (Details) (USD $)	12 Months Ended
	Dec. 31, 2014
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Number of Options (in shares)	444,278
Weighted Average Exercise Price (in dollars per share)	$43.56
Weighted Average Remaining Contractual Life (Years)	3 years 4 months 27 days
$27.00 - $38.00 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Range of Exercise Prices Lower Limit	$27
Range of Exercise Prices Upper Limit	$38
Number of Options (in shares)	25,857
Weighted Average Exercise Price (in dollars per share)	$27.70
Weighted Average Remaining Contractual Life (Years)	4 years 1 month 28 days
$38.01 - $42.00 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Range of Exercise Prices Lower Limit	$38.01
Range of Exercise Prices Upper Limit	$42
Number of Options (in shares)	82,834
Weighted Average Exercise Price (in dollars per share)	$41.77
Weighted Average Remaining Contractual Life (Years)	3 years 1 month 28 days
$42.01 - $45.00 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Range of Exercise Prices Lower Limit	$42.01
Range of Exercise Prices Upper Limit	$45
Number of Options (in shares)	221,487
Weighted Average Exercise Price (in dollars per share)	$43.93
Weighted Average Remaining Contractual Life (Years)	4 years 22 days
$45.01 - $50.00 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Range of Exercise Prices Lower Limit	$45.01
Range of Exercise Prices Upper Limit	$50
Number of Options (in shares)	114,100
Weighted Average Exercise Price (in dollars per share)	$47.75
Weighted Average Remaining Contractual Life (Years)	2 years 1 month 25 days

StockBased_Compensation_Restri

Stock-Based Compensation (Restricted Stock Award Activity) (Details) (Restricted Stock [Member], USD $)	12 Months Ended
In Millions, except Share data, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Restricted Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Fair value of awards vested (in millions)	$11	$8	$9
Restricted common shares awarded (in shares)	159,590	127,785	167,320
Weighted average market price of shares awarded	$70.09	$64.72	$53.71
Compensation cost charged against income (in millions)	$10	$23	$12

Stock_BasedCompensation_Stock_

Stock Based-Compensation (Stock Awards Activity Rollforward) (Details) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Restricted Stock (in shares):
Forfeitures	-10,730
Restricted Stock [Member]
Restricted Stock (in shares):
Balance at beginning of the period	492,329
Grants	159,590	127,785	167,320
Forfeitures	-16,841
Vested and issued	-218,760
Balance at end of period	416,318	492,329
Weighted Average Grant Date Fair Value (in dollars per share):
Balance at beginning of period	$53.76
Grants	$70.09	$64.72	$53.71
Forfeitures	$62.41
Vested and issued	$47.77
Balance at end of period	$62.82	$53.76

StockBased_Compensation_Perfor

Stock-Based Compensation (Performance Share Awards Compensation Expense) (Details) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Compensation Expense Recorded [Line Items]
Compensation expense	$103	$99	$83
Performance Shares [Member]
Compensation Expense Recorded [Line Items]
Compensation expense	93	77	71
Cash settlements	11	9	4
Stock settlements	$61	$56	$41

StockBased_Compensation_Perfor1

Stock-Based Compensation (Performance Share Awards Activity) (Details) (Performance Shares [Member], USD $)	12 Months Ended
	Dec. 31, 2014
Performance Shares [Member]
Performance Shares (in shares):
Balance at beginning of period	1,608,789
Grants	561,335
Forfeitures	-44,250
Payouts	-571,177
Balance at end of period	1,554,697
Weighted Average Grant Date Fair Value (in dollars per share):
Balance at beginning of period	$0
Grants	$69.32
Forfeitures	$69.16
Payouts	$0
Balance at end of period	$69.32

StockBased_Compensation_Unreco

Stock-Based Compensation (Unrecognized Compensation Costs) (Details) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2014
Share Based Compensation Unrecognized and Non-Vested Cost [Line Items]
Unrecognized Compensation Cost	$58
Weighted Average to be Recognized	11 months 25 days
Restricted Stock [Member]
Share Based Compensation Unrecognized and Non-Vested Cost [Line Items]
Unrecognized Compensation Cost	10
Weighted Average to be Recognized	1 year 23 days
Performance Shares [Member]
Share Based Compensation Unrecognized and Non-Vested Cost [Line Items]
Unrecognized Compensation Cost	$48
Weighted Average to be Recognized	11 months 22 days

StockBased_Compensation_Detail

Stock-Based Compensation (Details Textuals) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Authorized limit of common stock shares	14,500,000
Performance units price per unit	1
Weighted Average Remaining Contractual Term	3 years 4 months 27 days
Options vested (in shares)	0
Options grants in period	$0	$0	$0
Options, exercises, intrinsic value	$11,000,000	$12,000,000	$25,000,000
Stock option expense	$0	$0	$700,000
Employee Stock Option [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Maximum award per employee	500,000
Award expiration period	10 years
Award vesting period	3 years
Restricted Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Maximum award per employee	150,000
Performance Shares [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Maximum award per employee	300,000
Performance Unit [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Maximum award per employee	1,000,000

Segment_and_Related_Informatio2

Segment and Related Information (Details Textuals)	Dec. 31, 2014
	customers
Segment Reporting [Abstract]
Number of electric utility customers	2,100,000
Number of gas utility customers	1,200,000

Segment_and_Related_Informatio3

Segment and Related Information (Financial Data) (Details) (USD $)	3 Months Ended								12 Months Ended
In Millions, unless otherwise specified	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
Segment Reporting Information [Line Items]
Operating Revenues	$3,078	$2,595	$2,698	$3,930	$2,533	$2,387	$2,225	$2,516	$12,301	$9,661	$8,791
Depreciation, Depletion and Amortization									1,145	1,094	1,018
Interest income									-10	-9	-10
Interest Expense									429	436	440
Income Taxes									364	254	286
Net Income Attributable to DTE Energy Company	299	156	124	326	124	198	105	234	905	661	610
Total Assets	27,974				25,935				27,974	25,935	26,339
Goodwill	2,018				2,018				2,018	2,018	2,018
Capital Expenditures and Acquisitions									2,049	1,876	2,018
Continuing Operations [Member]
Segment Reporting Information [Line Items]
Operating Revenues											8,791
Depreciation, Depletion and Amortization											995
Interest income											-10
Interest Expense											440
Income Taxes											286
Net Income Attributable to DTE Energy Company											666
Total Assets											26,339
Goodwill											2,018
Capital Expenditures and Acquisitions											1,969
Discontinued Operations [Member]
Segment Reporting Information [Line Items]
Net Income Attributable to DTE Energy Company											-56
Total Assets											0
Goodwill											0
Capital Expenditures and Acquisitions											49
Operating Segments [Member] | Electric [Member]
Segment Reporting Information [Line Items]
Operating Revenues									5,283	5,199	5,293
Depreciation, Depletion and Amortization									933	902	827
Interest income									-1	-1	-1
Interest Expense									250	268	272
Income Taxes									296	252	280
Net Income Attributable to DTE Energy Company									528	484	483
Total Assets	18,715				17,508				18,715	17,508	17,755
Goodwill	1,208				1,208				1,208	1,208	1,208
Capital Expenditures and Acquisitions									1,561	1,325	1,230
Operating Segments [Member] | Gas [Member]
Segment Reporting Information [Line Items]
Operating Revenues									1,636	1,474	1,315
Depreciation, Depletion and Amortization									99	95	92
Interest income									-7	-7	-7
Interest Expense									57	58	59
Income Taxes									78	77	50
Net Income Attributable to DTE Energy Company									140	143	115
Total Assets	4,283				3,938				4,283	3,938	4,059
Goodwill	743				743				743	743	745
Capital Expenditures and Acquisitions									224	209	221
Operating Segments [Member] | Power and Industrial Projects [Member]
Segment Reporting Information [Line Items]
Operating Revenues									2,289	1,950	1,823
Depreciation, Depletion and Amortization									77	72	65
Interest income									-5	-6	-7
Interest Expense									28	27	37
Income Taxes									-100	-45	-44
Net Income Attributable to DTE Energy Company									90	66	42
Total Assets	1,009				1,067				1,009	1,067	991
Goodwill	26				26				26	26	26
Capital Expenditures and Acquisitions									77	93	281
Operating Segments [Member] | Gas Storage and Pipelines [Member]
Segment Reporting Information [Line Items]
Operating Revenues									203	132	96
Depreciation, Depletion and Amortization									34	23	8
Interest income									-6	-7	-8
Interest Expense									22	18	8
Income Taxes									53	45	39
Net Income Attributable to DTE Energy Company									82	70	61
Total Assets	884				824				884	824	668
Goodwill	24				24				24	24	22
Capital Expenditures and Acquisitions									184	245	233
Operating Segments [Member] | Energy Trading [Member]
Segment Reporting Information [Line Items]
Operating Revenues									3,762	1,771	1,109
Depreciation, Depletion and Amortization									1	1	2
Interest income									0	0	0
Interest Expense									7	8	8
Income Taxes									77	-38	7
Net Income Attributable to DTE Energy Company									122	-58	12
Total Assets	755				623				755	623	629
Goodwill	17				17				17	17	17
Capital Expenditures and Acquisitions									3	3	1
Operating Segments [Member] | Corporate and Other [Member]
Segment Reporting Information [Line Items]
Operating Revenues									2	3	3
Depreciation, Depletion and Amortization									1	1	1
Interest income									-48	-51	-52
Interest Expense									122	120	121
Income Taxes									-40	-37	-46
Net Income Attributable to DTE Energy Company									-57	-44	-47
Total Assets	3,209				2,945				3,209	2,945	3,074
Goodwill	0				0				0	0	0
Capital Expenditures and Acquisitions									0	1	3
Intersegment Eliminations [Member]
Segment Reporting Information [Line Items]
Operating Revenues									-874	-868	-848
Depreciation, Depletion and Amortization									0	0	0
Interest income									57	63	65
Interest Expense									-57	-63	-65
Income Taxes									0	0	0
Net Income Attributable to DTE Energy Company									0	0	0
Total Assets	-881				-970				-881	-970	-837
Goodwill	0				0				0	0	0
Capital Expenditures and Acquisitions									0	0	0
Intersegment Eliminations [Member] | Discontinued Operations [Member]
Segment Reporting Information [Line Items]
Operating Revenues									0	0	-2
Intersegment Eliminations [Member] | Electric [Member] | Continuing Operations [Member]
Segment Reporting Information [Line Items]
Operating Revenues									-29	-26	-29
Intersegment Eliminations [Member] | Gas [Member] | Continuing Operations [Member]
Segment Reporting Information [Line Items]
Operating Revenues									-6	-4	-4
Intersegment Eliminations [Member] | Power and Industrial Projects [Member] | Continuing Operations [Member]
Segment Reporting Information [Line Items]
Operating Revenues									-794	-816	-801
Intersegment Eliminations [Member] | Gas Storage and Pipelines [Member] | Continuing Operations [Member]
Segment Reporting Information [Line Items]
Operating Revenues									-9	-3	-6
Intersegment Eliminations [Member] | Energy Trading [Member] | Continuing Operations [Member]
Segment Reporting Information [Line Items]
Operating Revenues									-33	-43	-43
Intersegment Eliminations [Member] | Corporate and Other [Member] | Continuing Operations [Member]
Segment Reporting Information [Line Items]
Operating Revenues									($3)	$24	$37

Supplementary_Quarterly_Financ2

Supplementary Quarterly Financial Information (Unaudited) (Details) (USD $)	3 Months Ended								12 Months Ended
In Millions, except Per Share data, unless otherwise specified	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

Subsequent_Event_Details

Subsequent Event (Details) (Electric [Member], Subsequent Event [Member], USD $)	0 Months Ended
In Millions, unless otherwise specified	Jan. 21, 2015
Electric [Member] | Subsequent Event [Member]
Subsequent Event [Line Items]
Payments to acquire business	$240

Valuation_and_Qualifying_Accou2

Valuation and Qualifying Accounts Valuation and Qualifying Accounts (Details) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at Beginning of Period	$55	$62	$162
Charged to cost and expenses	95	94	79
Charged to other accounts	20	23	16
Deductions	-116	-124	-195
Balance at End of Period	$54	$55	$62