DTE Electric 10-Q 23 Oct 15 2015 Q3 Quarterly report Financial data

Document and Entity Information

Document and Entity Information	9 Months Ended
	Sep. 30, 2015shares
Entity Registrant Name	DTE ENERGY CO
Entity Central Index Key	936,340
Current Fiscal Year End Date	--12-31
Entity Filer Category	Large Accelerated Filer
Document Type	10-Q
Document Period End Date	Sep. 30, 2015
Document Fiscal Year Focus	2,015
Document Fiscal Period Focus	Q3
Amendment Flag	false
Entity Common Stock, Shares Outstanding	179,475,625
DTE Electric
Entity Registrant Name	DTE ELECTRIC CO
Entity Central Index Key	28,385
Current Fiscal Year End Date	--12-31
Entity Filer Category	Non-accelerated Filer
Document Type	10-Q
Document Period End Date	Sep. 30, 2015
Document Fiscal Year Focus	2,015
Document Fiscal Period Focus	Q3
Amendment Flag	false
Entity Common Stock, Shares Outstanding	138,632,324

Consolidated Statements of Oper

Consolidated Statements of Operations (Unaudited) - USD ($) shares in Millions, $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Operating Revenues	$ 2,598	$ 2,595	$ 7,850	$ 9,223
Operating Expenses
Fuel, purchased power, and gas	1,053	1,119	3,393	4,550
Operation and maintenance	817	860	2,436	2,512
Depreciation and amortization	196	293	625	855
Taxes other than income	91	86	282	268
Asset (gains) losses and impairments, net	1	(2)	9	(10)
Total operating expenses	2,158	2,356	6,745	8,175
Operating Income	440	239	1,105	1,048
Other (Income) and Deductions
Interest expense	116	107	341	323
Interest income	(4)	(2)	(10)	(7)
Other income	(55)	(55)	(155)	(136)
Other expenses	17	11	36	29
Total Other (Income) and Deductions	74	61	212	209
Income Before Income Taxes	366	178	893	839
Income Tax Expense	102	21	250	229
Net Income	264	157	643	610
Less: Net Income (Loss) Attributable to Noncontrolling Interests	(1)	1	(4)	4
Net Income Attributable to DTE Energy Company/DTE Electric	$ 265	$ 156	$ 647	$ 606
Basic Earnings per Common Share
Net Income Attributable to DTE Energy Company (in dollars per share)	$ 1.47	$ 0.88	$ 3.61	$ 3.42
Diluted Earnings per Common Share
Net Income Attributable to DTE Energy Company (in dollars per share)	$ 1.47	$ 0.88	$ 3.61	$ 3.42
Weighted Average Common Shares Outstanding
Basic (in shares)	179	177	179	177
Diluted (in shares)	180	177	179	177
Dividends Declared per Common Share (in dollars per share)	$ 0.73	$ 0.69	$ 2.11	$ 2
DTE Electric
Operating Revenues	$ 1,385	$ 1,357	$ 3,735	$ 4,048
Operating Expenses
Fuel, purchased power, and gas	441	430	1,212	1,328
Operation and maintenance	330	351	966	1,022
Depreciation and amortization	141	238	461	695
Taxes other than income	73	66	214	202
Asset (gains) losses and impairments, net	0	0	0	(1)
Total operating expenses	985	1,085	2,853	3,246
Operating Income	400	272	882	802
Other (Income) and Deductions
Interest expense	66	65	196	189
Other income	(14)	(15)	(42)	(45)
Other expenses	15	11	32	26
Total Other (Income) and Deductions	67	61	186	170
Income Before Income Taxes	333	211	696	632
Income Tax Expense	117	75	244	229
Net Income Attributable to DTE Energy Company/DTE Electric	$ 216	$ 136	$ 452	$ 403

Consolidated Statements of Comp

Consolidated Statements of Comprehensive Income (Unaudited) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Net Income	$ 264	$ 157	$ 643	$ 610
Net Income	265	156	647	606
Other comprehensive income (loss), net of tax:
Benefit obligations, net of taxes	3	2	9	3
Net unrealized gains on investments during the period, net of taxes of $—, $—, $—, and $—, respectively	0	0	0	1
Foreign currency translation	(2)	(1)	(4)	(1)
Other comprehensive income	1	1	5	3
Comprehensive income	265	158	648	613
Less comprehensive income (loss) attributable to noncontrolling interests	(1)	1	(4)	4
Comprehensive income attributable to DTE Energy Company/DTE Electric	266	157	652	609
DTE Electric
Net Income	216	136	452	403
Other comprehensive income (loss), net of tax:
Transfer of benefit obligations, net of taxes of $—, $—, $18, and $—, respectively	0	0	28	0
Benefit obligations, net of taxes	0	1	0	0
Comprehensive income attributable to DTE Energy Company/DTE Electric	$ 216	$ 137	$ 480	$ 403

Consolidated Statements of Com4

Consolidated Statements of Comprehensive Income (Parentheticals) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Tax effect on benefit obligation	$ 2	$ 1	$ 6	$ 2
Tax effect on net unrealized gains on investments	0	0	0	0
DTE Electric
Tax effect on benefit obligation - transfer	0	0	18	0
Tax effect on benefit obligation	$ 0	$ 0	$ 0	$ 0

Consolidated Statements of Fina

Consolidated Statements of Financial Position (Unaudited) - USD ($) $ in Millions	Sep. 30, 2015	Dec. 31, 2014
Current Assets
Cash and cash equivalents	$ 67	$ 48
Restricted cash	21	120
Accounts receivable (less allowance for doubtful accounts)
Customer	1,242	1,504
Other	79	94
Inventories
Fuel and gas	533	512
Materials and supplies	307	292
Notes receivable
Derivative assets	90	128
Regulatory assets	15	76
Other	346	313
Total Current Assets	2,700	3,087
Investments
Nuclear decommissioning trust funds	1,199	1,241
Other	684	628
Total Investments	1,883	1,869
Property
Property, plant, and equipment	28,014	26,538
Less accumulated depreciation and amortization	(10,147)	(9,718)
Property, plant and equipment, net	17,867	16,820
Other Assets
Goodwill	2,018	2,018
Regulatory assets	3,719	3,651
Securitized regulatory assets	0	34
Intangible assets	89	102
Notes receivable	82	90
Derivative assets	48	44
Other	248	259
Total Noncurrent Assets	6,204	6,198
Total Assets	28,654	27,974
Accounts payable
Accounts payable	835	973
Accrued interest	119	86
Dividends payable	131	122
Short-term borrowings	185	398
Current portion long-term debt, including capital leases	468	274
Derivative liabilities	56	77
Regulatory liabilities	67	153
Short-term borrowings
Other	412	494
Total Current Liabilities	2,273	2,577
Long-Term Debt (net of current portion)
Mortgage bonds, notes, and other	8,368	7,860
Junior subordinated debentures	480	480
Capital lease obligations	8	3
Total Long-Term Debt (net of current portion)	8,856	8,343
Other Liabilities
Deferred income taxes	4,022	3,776
Regulatory liabilities	598	667
Asset retirement obligations	2,180	1,962
Unamortized investment tax credit	50	41
Derivative liabilities	27	8
Accrued pension liability	1,120	1,280
Accrued postretirement liability	302	515
Nuclear decommissioning	174	182
Other	219	281
Total Noncurrent Liabilities	$ 8,692	$ 8,712
Commitments and Contingencies
Equity
Common stock	$ 4,117	$ 3,904
Retained earnings	4,845	4,578
Accumulated other comprehensive income (loss)	(150)	(155)
Total Equity Attributable to DTE Energy Company/DTE Electric	8,812	8,327
Noncontrolling interests	21	15
Total Equity	8,833	8,342
Total Liabilities and Equity	28,654	27,974
DTE Electric
Current Assets
Cash and cash equivalents	29	14
Restricted cash	0	96
Accounts receivable (less allowance for doubtful accounts)
Customer	730	688
Affiliates	69	31
Other	38	15
Inventories
Fuel and gas	267	269
Materials and supplies	250	231
Notes receivable
Affiliates	4	8
Other	6	8
Regulatory assets	3	46
Prepaid property tax	96	44
Other	27	31
Total Current Assets	1,519	1,481
Investments
Nuclear decommissioning trust funds	1,199	1,241
Other	34	172
Total Investments	1,233	1,413
Property
Property, plant, and equipment	21,045	19,805
Less accumulated depreciation and amortization	(7,586)	(7,216)
Property, plant and equipment, net	13,459	12,589
Other Assets
Regulatory assets	3,002	2,913
Securitized regulatory assets	0	34
Intangible assets	39	37
Other	171	182
Total Noncurrent Assets	3,212	3,166
Total Assets	19,423	18,649
Accounts payable
Affiliates	41	60
Other	360	366
Accrued interest	68	58
Current portion long-term debt, including capital leases	153	118
Regulatory liabilities	36	150
Short-term borrowings
Affiliates	68	84
Other	46	50
Other	159	151
Total Current Liabilities	931	1,037
Long-Term Debt (net of current portion)
Mortgage bonds, notes, and other	5,492	5,144
Capital lease obligations	8	0
Total Long-Term Debt (net of current portion)	5,500	5,144
Other Liabilities
Deferred income taxes	3,454	3,188
Regulatory liabilities	218	245
Asset retirement obligations	2,007	1,796
Unamortized investment tax credit	45	36
Nuclear decommissioning	174	182
Accrued pension liability — affiliates	985	1,200
Accrued postretirement liability — affiliates	356	520
Other	74	105
Total Noncurrent Liabilities	$ 7,313	$ 7,272
Commitments and Contingencies
Equity
Common stock	$ 4,086	$ 3,786
Retained earnings	1,591	1,436
Accumulated other comprehensive income (loss)	2	(26)
Total Equity Attributable to DTE Energy Company/DTE Electric	5,679	5,196
Total Liabilities and Equity	$ 19,423	$ 18,649

Consolidated Statements of Fin6

Consolidated Statements of Financial Position (Unaudited) (Parenthetical) - USD ($) $ in Millions	Sep. 30, 2015	Dec. 31, 2014
Allowance for doubtful accounts	$ 56	$ 54
Shareholder’s Equity
Common stock, par value (in dollars per share)
Common stock, shares authorized (in shares)	400,000,000	400,000,000
Common stock, shares issued (in shares)	179,475,625	176,991,231
Common stock, shares outstanding (in shares)	179,475,625	176,991,231
DTE Electric
Allowance for doubtful accounts	$ 29	$ 29
Shareholder’s Equity
Common stock, par value (in dollars per share)	$ 10	$ 10
Common stock, shares authorized (in shares)	400,000,000	400,000,000
Common stock, shares issued (in shares)	138,632,324	138,632,324
Common stock, shares outstanding (in shares)	138,632,324	138,632,324

Consolidated Statements of Cash

Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014
Operating Activities
Net Income	$ 643	$ 610
Net Income	647	606
Adjustments to reconcile Net Income to net cash from operating activities:
Depreciation and amortization	625	855
Nuclear fuel amortization	40	33
Allowance for equity funds used during construction	(16)	(16)
Deferred income taxes	251	244
Asset (gains) losses and impairments, net	9	(10)
Changes in assets and liabilities:
Accounts receivable, net	277	273
Inventories	(36)	(165)
Accounts payable	(125)	48
Accrued pension obligation	(160)	(154)
Accrued postretirement obligation	(213)	(64)
Derivative assets and liabilities	32	(56)
Regulatory assets and liabilities	35	(211)
Other current and noncurrent assets and liabilities	106	(89)
Net cash from operating activities	1,468	1,298
Investing Activities
Plant and equipment expenditures — utility	(1,239)	(1,295)
Plant and equipment expenditures — non-utility	(162)	(207)
Acquisition	(241)	0
Proceeds from sale of assets	16	36
Restricted cash for debt redemption, principally Securitization	99	62
Proceeds from sale of nuclear decommissioning trust fund assets	627	652
Investment in nuclear decommissioning trust funds	(638)	(665)
Other	(34)	(40)
Net cash used for investing activities	(1,572)	(1,457)
Financing Activities
Issuance of long-term debt, net of issuance costs	956	1,289
Redemption of long-term debt	(260)	(1,222)
Short-term borrowings, net	(213)	522
Issuance of common stock	9	0
Repurchase of common stock	0	(52)
Dividends on common stock	(370)	(348)
Other	1	(22)
Net cash from financing activities	123	167
Net Increase in Cash and Cash Equivalents	19	8
Cash and Cash Equivalents at Beginning of Period	48	52
Cash and Cash Equivalents at End of Period	67	60
Supplemental disclosure of non-cash investing and financing activities
Plant and equipment expenditures in accounts payable	185	192
DTE Electric
Operating Activities
Net Income	452	403
Adjustments to reconcile Net Income to net cash from operating activities:
Depreciation and amortization	461	695
Nuclear fuel amortization	40	33
Allowance for equity funds used during construction	(15)	(16)
Deferred income taxes	269	199
Asset (gains) losses and impairments, net	0	(1)
Changes in assets and liabilities:
Accounts receivable, net	(103)	36
Inventories	(17)	(38)
Accounts payable	3	7
Accrued pension liability — affiliates	(215)	(122)
Accrued postretirement liability — affiliates	(164)	(42)
Regulatory assets and liabilities	(12)	(163)
Other current and noncurrent assets and liabilities	9	(113)
Net cash from operating activities	708	879
Investing Activities
Plant and equipment expenditures	(1,045)	(1,143)
Acquisition	(241)	0
Restricted cash for debt redemption, principally Securitization	96	60
Notes receivable from affiliate	4	164
Proceeds from sale of nuclear decommissioning trust fund assets	627	652
Investment in nuclear decommissioning trust funds	(638)	(665)
Transfer of Rabbi Trust assets to affiliate	137	0
Other	9	(16)
Net cash used for investing activities	(1,051)	(948)
Financing Activities
Issuance of long-term debt, net of issuance costs	495	942
Redemption of long-term debt	(115)	(837)
Capital contribution by parent company	300	0
Short-term borrowings, net — other	(4)	254
Short-term borrowings, net — affiliate	(16)	(2)
Dividends on common stock	(297)	(277)
Other	(5)	(10)
Net cash from financing activities	358	70
Net Increase in Cash and Cash Equivalents	15	1
Cash and Cash Equivalents at Beginning of Period	14	27
Cash and Cash Equivalents at End of Period	29	28
Supplemental disclosure of non-cash investing and financing activities
Plant and equipment expenditures in accounts payable	$ 134	$ 139

Consolidated Statements of Chan

Consolidated Statements of Changes in Equity (Unaudited) - 9 months ended Sep. 30, 2015 - USD ($) $ in Millions	Total	Common Stock	Retained Earnings	Accumulated Other Comprehensive Income (Loss)	Non-Controlling Interests	DTE Electric	DTE ElectricCommon Stock	DTE ElectricAdditional Paid-in Capital	DTE ElectricRetained Earnings	DTE ElectricAccumulated Other Comprehensive Income (Loss)
Beginning Balance, shares at Dec. 31, 2014	176,991,231	176,991,000				138,632,324	138,632,000
Beginning Balance at Dec. 31, 2014	$ 8,342	$ 3,904	$ 4,578	$ (155)	$ 15
Beginning Balance at Dec. 31, 2014	8,327					$ 5,196	$ 1,386	$ 2,400	$ 1,436	$ (26)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net Income (Loss)	643		647		(4)
Net Income	647					452			452
Dividends declared on common stock	(379)		(379)			(297)			(297)
Issuance of common stock, shares		105,000
Issuance of common stock	9	$ 9
Contribution of common stock to VEBA Trust, shares		1,428,000
Contribution of common stock to VEBA Trust	117	$ 117
Benefit obligations, net of taxes	9			9		0
Transfer of benefit obligations, net of taxes						28				28
Foreign currency translation	(4)			(4)
Stock-based compensation, distributions to noncontrolling interests and other, shares		952,000
Stock-based compensation, contributions, and distributions to noncontrolling interests and other	$ 96	$ 87	(1)		10
Capital contribution by parent company						$ 300		300
Ending Balance, shares at Sep. 30, 2015	179,475,625	179,476,000				138,632,324	138,632,000
Ending Balance at Sep. 30, 2015	$ 8,833	$ 4,117	$ 4,845	$ (150)	$ 21
Ending Balance at Sep. 30, 2015	$ 8,812					$ 5,679	$ 1,386	$ 2,700	$ 1,591	$ 2

Organization and Basis of Prese

Organization and Basis of Presentation	9 Months Ended
	Sep. 30, 2015
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 Registrants are regulated by other federal and state regulatory agencies including the NRC, the EPA, the MDEQ, and the CFTC. Basis of Presentation The Consolidated Financial Statements should be read in conjunction with the Notes to Consolidated Financial Statements included in the DTE Energy 2014 Annual Report on Form 10-K and the Notes to Consolidated Financial Statements included in the DTE Electric 2014 Annual Report on Form 10-K. The accompanying Consolidated Financial Statements of the Registrants 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 Registrants' estimates. The Consolidated Financial Statements are unaudited, but in the Registrants' opinions include all adjustments necessary to present a fair statement of the results for the interim periods. All adjustments are of a normal recurring nature, except as otherwise disclosed in these Consolidated Financial Statements and Combined Notes to Consolidated Financial Statements. Financial results for this interim period are not necessarily indicative of results that may be expected for any other interim period or for the fiscal year ending December 31, 2015. The information in these combined notes relates to each of the Registrants as noted in the Index of Combined Notes to Consolidated Financial Statements. However, DTE Electric does not make any representation as to information related solely to DTE Energy or the subsidiaries of DTE Energy other than itself. Certain prior year balances for the Registrants were reclassified to match current year's financial statement presentation. Principles of Consolidation The Registrants consolidate all majority-owned subsidiaries and investments in entities in which they have controlling influence. Non-majority owned investments are accounted for using the equity method when the Registrants are able to influence the operating policies of the investee. When the Registrants do not influence the operating policies of an investee, the cost method is used. These Consolidated Financial Statements also reflect the Registrants' proportionate interests in certain jointly-owned utility plants. The Registrants eliminate all intercompany balances and transactions. The Registrants evaluate whether an entity is a VIE whenever reconsideration events occur. The Registrants consolidate VIEs for which they are the primary beneficiary. If a Registrant 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, a Registrant 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 Registrants perform ongoing reassessments of all VIEs to determine if the primary beneficiary status has changed. Legal entities within DTE Energy'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 DTE Energy retaining operational and customer default risk. These entities generally are VIEs and consolidated when DTE Energy is the primary beneficiary. In addition, DTE Energy has interests in certain VIEs through which control of all significant activities is shared with partners, and therefore are accounted for under the equity method. DTE Energy has variable interests in VIEs through certain of its long-term purchase and sale contracts. DTE Electric has variable interests in VIEs through certain of its long-term purchase contracts. As of September 30, 2015 , the carrying amount of assets and liabilities in the Registrants' 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 Registrants for the deliveries associated with the current billing cycle under the contracts. The Registrants have 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 DTE Energy's variable interests through these long-term purchase and sale contracts. In addition, there is no significant potential exposure to loss as a result of DTE Electric's variable interests through these long-term purchase 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 performed servicing activities including billing and collecting surcharge revenue for Securitization. The remaining amounts due on the rate reduction bonds were paid in March 2015. The associated regulatory assets were fully amortized by March 31, 2015. Securitization has an over-recovery of funds. DTE Electric began to return the funds to customers in September 2015. Remaining funds are expected to be returned to customers during the fourth quarter of 2015 . Subsequent to the pay-down of the bonds, Securitization is no longer a VIE but continues to be consolidated by the Registrants as a voting interest entity. The maximum risk exposure for consolidated VIEs is reflected on the Registrants' 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 Consolidated Statements of Financial Position items for consolidated VIEs as of September 30, 2015 and December 31, 2014 . 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. Securitization, included in the DTE Energy table below for December 31, 2014 , also relates to DTE Electric. VIEs, in which DTE Energy 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. September 30, 2015 December 31, 2014 Total Securitization Other Total (In millions) ASSETS Cash and cash equivalents $ 12 $ — $ 7 $ 7 Restricted cash 6 96 8 104 Accounts receivable 14 26 15 41 Inventories 43 — 67 67 Property, plant, and equipment, net 70 — 81 81 Securitized regulatory assets — 34 — 34 Other current and long-term assets 4 1 6 7 $ 149 $ 157 $ 184 $ 341 LIABILITIES Accounts payable and accrued current liabilities $ 11 $ 3 $ 8 $ 11 Current portion long-term debt, including capital leases 9 105 10 115 Current regulatory liabilities — 32 — 32 Mortgage bonds, notes, and other 11 — 15 15 Capital lease obligations — — 3 3 Other current and long-term liabilities 6 9 6 15 $ 37 $ 149 $ 42 $ 191 Amounts for DTE Energy's non-consolidated VIEs as of September 30, 2015 and December 31, 2014 are as follows: September 30, 2015 December 31, 2014 (In millions) Other investments $ 138 $ 134 Notes receivable $ 15 $ 15

Significant Accounting Policies

Significant Accounting Policies	9 Months Ended
	Sep. 30, 2015
Accounting Policies [Abstract]
Significant Accounting Policies	SIGNIFICANT ACCOUNTING POLICIES Other Income Other income for the Registrants is recognized for non-operating income such as equity earnings, allowance for equity funds used during construction, and contract services. DTE Energy's Power & Industrial Projects segment 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 $24 million and $25 million of Other income for the three months ended September 30, 2015 and 2014, respectively , and approximately $64 million and $57 million of Other income for the nine months ended September 30, 2015 and 2014, respectively . Changes in Accumulated Other Comprehensive Income (Loss) For the three and nine months ended September 30, 2015 and 2014 , reclassifications out of Accumulated other comprehensive income (loss) for the Registrants were not material. Refer to Note 13 to the Consolidated Financial Statements, " Retirement Benefits and Trusteed Assets ", regarding the transfer of a portion of DTE Electric benefit obligations during the year. Changes in Accumulated other comprehensive income (loss) are presented in DTE Energy's Consolidated Statements of Changes in Equity and DTE Electric's Consolidated Statements of Changes in Shareholder's Equity. Intangible Assets DTE Energy has certain intangible assets relating to emission allowances, renewable energy credits and non-utility contracts as shown below: September 30, December 31, 2015 2014 (In millions) Emission allowances $ 1 $ 1 Renewable energy credits 49 45 Contract intangible assets 109 122 159 168 Less accumulated amortization 59 57 Intangible assets, net 100 111 Less current intangible assets 11 9 $ 89 $ 102 DTE Electric has certain intangible assets relating to emission allowances and renewable energy credits as shown below: September 30, December 31, 2015 2014 (In millions) Emission allowances $ 1 $ 1 Renewable energy credits 49 45 50 46 Less current intangible assets 11 9 $ 39 $ 37 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 businesses by the Registrants. DTE Energy amortizes contract intangible assets on a straight-line basis over the expected period of benefit, ranging from 1 to 26 years. Income Taxes The effective tax rate and unrecognized tax benefits of the Registrants are as follows: Effective Tax Rate Unrecognized Tax Benefits Three Months Ended September 30, Nine Months Ended September 30, September 30, 2015 2014 2015 2014 2015 (In millions) DTE Energy 28 % 12 % 28 % 27 % $ 3 DTE Electric 35 % 36 % 35 % 36 % $ 4 The increase in DTE Energy's effective tax rate for the three months ended September 30, 2015 is primarily due to higher annual forecasted production tax credits in 2014 as compared to 2015. The increase in DTE Energy's effective tax rate for the nine months ended September 30, 2015 is primarily due to lower production tax credits partially offset by the inclusion in 2014 of $8 million of deferred tax expense resulting from the New York state income tax reform enacted on March 31, 2014. The decrease in DTE Electric's effective tax rate for the three and nine months ended September 30, 2015 is due primarily to higher production tax credits in 2015. If recognized, $2 million of the unrecognized tax benefits of the Registrants would favorably impact their effective tax rates. During the 2015 third quarter, there was a decrease of $6 million of unrecognized tax benefits at DTE Energy due to the expiration of statute of limitations. The $6 million decrease did not impact tax expense because the unrecognized tax benefit was offset by a net operating loss. The Registrants do not anticipate any material changes to the unrecognized tax benefits in the next twelve months. DTE Electric had income tax receivables with DTE Energy of $68 million and $29 million at September 30, 2015 and December 31, 2014 , respectively.

New Accounting Pronouncements

New Accounting Pronouncements	9 Months Ended
	Sep. 30, 2015
New Accounting Pronouncements and Changes in Accounting Principles [Abstract]
New Accounting Pronouncements	NEW ACCOUNTING PRONOUNCEMENTS In May 2014, the FASB issued 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. In July 2015, the FASB deferred implementation of the revenue standard to be effective for the first interim period within annual reporting periods beginning after December 15, 2017. The standard is to be applied retrospectively and early adoption is permitted in the preceding year. The Registrants are currently assessing the impact of this ASU on their Consolidated Financial Statements. In February 2015, the FASB issued ASU No. 2015-02, Amendments to the Consolidation Analysis , which changes the analysis that a reporting entity must perform to determine whether it should consolidate certain types of legal entities. The ASU affects (1) limited partnerships and similar legal entities, (2) evaluating fees paid to a decision maker or a service provider as a variable interest, (3) the effect of fee arrangements on the primary beneficiary determination, (4) the effect of related parties on the primary beneficiary determination, and (5) certain investment funds. It is effective for the Registrants for the first interim period within annual reporting periods beginning on or after December 15, 2015 and early adoption is permitted. The Registrants are currently assessing the impact of this ASU on their Consolidated Financial Statements. In April 2015, the FASB issued ASU No. 2015-03, Simplifying the Presentation of Debt Issuance Costs . This ASU requires that debt issuance costs related to a recognized debt liability be presented in the balance sheet as a direct deduction from the carrying amount of that debt liability, consistent with debt discounts. This ASU is effective for reporting periods beginning after December 15, 2015 and interim periods therein. It is to be applied retrospectively and early adoption is permitted. The adoption of this ASU will not have a significant impact on the Registrants' Consolidated Statements of Financial Position. In July 2015, the FASB issued ASU No. 2015-11, Inventory (Topic 330), Simplifying the Measurement of Inventory . The ASU replaces the current lower of cost or market test with a lower of cost or net realizable value test when cost is determined on a first-in, first-out or average cost basis. The standard is effective for public entities for annual reporting periods beginning after December 15, 2016, and interim periods therein. It is to be applied prospectively and early adoption is permitted. The ASU will not have a significant impact on the Registrants' Consolidated Statements of Financial Position.

Acquisitions

Acquisitions	9 Months Ended
	Sep. 30, 2015
Business Combinations [Abstract]
Acquisitions	ACQUISITIONS On January 21, 2015, DTE Electric closed on an acquisition of a 732 MW simple-cycle natural gas facility in Carson City, Michigan from The LS Power Group. The facility will serve to meet customer needs during periods of peak demand. DTE Electric has completed its valuation analysis to arrive at the fair value of the assets acquired. The cash consideration and total purchase price of approximately $241 million was allocated based on the underlying fair value of the assets acquired, which was primarily Property, plant, and equipment. The pro forma results of operations have not been presented for DTE Electric as the effects of the acquisition were not material to either Registrant's Consolidated Statements of Operations. On October 1, 2015, DTE Electric closed on an acquisition of a 350 MW simple-cycle natural gas facility in East China Township, Michigan from a non-utility affiliate of DTE Energy. The facility will serve to meet customer needs during periods of peak demand. DTE Electric has completed its purchase accounting. The cash consideration and total purchase price of approximately $69 million was based on the net book value of the assets acquired, which was primarily Property, plant, and equipment. The pro forma results of operations have not been presented for DTE Electric as the effects of the acquisition were not material to its Consolidated Statements of Operations.

Asset Retirement Obligations

Asset Retirement Obligations	9 Months Ended
	Sep. 30, 2015
Asset Retirement Obligation Disclosure [Abstract]
Asset Retirement Obligations	ASSET RETIREMENT OBLIGATIONS A reconciliation of the ARO for the nine months ended September 30, 2015 follows: DTE Energy DTE Electric (In millions) Asset retirement obligations at December 31, 2014 $ 1,962 $ 1,796 Accretion 90 83 Revision in estimated cash flows 128 128 Asset retirement obligations at September 30, 2015 $ 2,180 $ 2,007 The Revision in estimated cash flows was principally attributed to the impact of the Coal Combustion Residual Rule on DTE Electric's coal ash storage facility AROs. Refer to Note 12 to the Consolidated Financial Statements, " Commitments and Contingencies ", for discussion of the implications of the Coal Combustion Residual Rule.

Regulatory Matters

Regulatory Matters	9 Months Ended
	Sep. 30, 2015
Public Utilities, General Disclosures [Abstract]
Regulatory Matters	REGULATORY MATTERS 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. On July 1, 2015, DTE Electric realized a rate increase of $230 million consisting of $190 million of self-implemented base rate increase related to the December 19, 2014 rate request and $40 million associated with the required elimination of a credit surcharge. A final order in this rate case is expected in December 2015. Customer Settlement In July 2014, an industrial customer of DTE Electric filed a complaint with the MPSC alleging they had been overcharged for the period of February 2008 through March 2014, and sought payment from DTE Electric of $22 million , plus interest. In July 2015, the MPSC issued an order that found the customer is entitled to a refund in the amount of $20 million , plus interest calculated at 7% per annum, until the refund is paid in full. In July 2015, DTE Electric issued a customer refund of $25 million , inclusive of interest. Approximately $16 million of the refund obligation is expected to be recovered through the PSCR and other regulatory mechanisms. DTE Electric does not expect this order to have a material impact to its Consolidated Statements of Operations.

Earnings Per Share

Earnings Per Share	9 Months Ended
	Sep. 30, 2015
Earnings Per Share [Abstract]
Earnings Per Share	EARNINGS PER SHARE DTE Energy 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 for the three and nine months ended September 30 : Three Months Ended September 30, Nine Months Ended September 30, 2015 2014 2015 2014 (In millions, except per share amounts) Basic Earnings per Share Net Income Attributable to DTE Energy Company $ 265 $ 156 $ 647 $ 606 Average number of common shares outstanding 179 177 179 177 Dividends declared — common shares $ 131 $ 122 $ 378 $ 353 Dividends declared — net restricted shares — — 1 1 Total distributed earnings $ 131 $ 122 $ 379 $ 354 Net Income less distributed earnings $ 134 $ 34 $ 268 $ 252 Distributed (dividends per common share) $ 0.73 $ 0.69 $ 2.11 $ 2.00 Undistributed 0.74 0.19 1.50 1.42 Total Basic Earnings per Common Share $ 1.47 $ 0.88 $ 3.61 $ 3.42 Diluted Earnings per Share Net Income Attributable to DTE Energy Company $ 265 $ 156 $ 647 $ 606 Average number of common shares outstanding 180 177 179 177 Dividends declared — common shares $ 131 $ 122 $ 378 $ 353 Dividends declared — net restricted shares — — 1 1 Total distributed earnings $ 131 $ 122 $ 379 $ 354 Net Income less distributed earnings $ 134 $ 34 $ 268 $ 252 Distributed (dividends per common share) $ 0.73 $ 0.69 $ 2.11 $ 2.00 Undistributed 0.74 0.19 1.50 1.42 Total Diluted Earnings per Common Share $ 1.47 $ 0.88 $ 3.61 $ 3.42

Fair Value

Fair Value	9 Months Ended
	Sep. 30, 2015
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 Registrants make certain assumptions they believe 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 Registrants and their counterparties is incorporated in the valuation of assets and liabilities through the use of credit reserves, the impact of which was immaterial at September 30, 2015 and December 31, 2014 . The Registrants believe they use 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 Registrants classify 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 Registrants have 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 for DTE Energy measured and recorded at fair value on a recurring basis as of September 30, 2015 and December 31, 2014 : September 30, 2015 December 31, 2014 Level 1 Level 2 Level 3 Netting Net Balance Level 1 Level 2 Level 3 Netting Net Balance (In millions) Assets: Cash equivalents (b) $ 11 $ 3 $ — $ — $ 14 $ 13 $ 99 $ — $ — $ 112 Nuclear decommissioning trusts 742 457 — — 1,199 792 449 — — 1,241 Other investments (c) 127 18 — — 145 100 50 — — 150 Derivative assets: Commodity Contracts: Natural Gas 162 87 54 (244 ) 59 555 140 92 (681 ) 106 Electricity — 204 47 (179 ) 72 — 295 47 (280 ) 62 Other 17 — 5 (17 ) 5 42 — 3 (42 ) 3 Other derivative contracts (d) — 10 — (8 ) 2 — 4 — (3 ) 1 Total derivative assets 179 301 106 (448 ) 138 597 439 142 (1,006 ) 172 Total $ 1,059 $ 779 $ 106 $ (448 ) $ 1,496 $ 1,502 $ 1,037 $ 142 $ (1,006 ) $ 1,675 Liabilities: Derivative liabilities: Commodity Contracts: Natural Gas $ (195 ) $ (49 ) $ (33 ) $ 249 $ (28 ) $ (578 ) $ (78 ) $ (62 ) $ 679 $ (39 ) Electricity — (200 ) (44 ) 190 (54 ) — (290 ) (52 ) 298 (44 ) Other (13 ) (4 ) (6 ) 22 (1 ) (32 ) (9 ) (4 ) 45 — Other derivative contracts (d) — (7 ) — 7 — — (5 ) — 3 (2 ) Total derivative liabilities (208 ) (260 ) (83 ) 468 (83 ) (610 ) (382 ) (118 ) 1,025 (85 ) Total $ (208 ) $ (260 ) $ (83 ) $ 468 $ (83 ) $ (610 ) $ (382 ) $ (118 ) $ 1,025 $ (85 ) Net Assets (Liabilities) at the end of the period $ 851 $ 519 $ 23 $ 20 $ 1,413 $ 892 $ 655 $ 24 $ 19 $ 1,590 Assets: Current $ 159 $ 225 $ 78 $ (358 ) $ 104 $ 582 $ 504 $ 109 $ (955 ) $ 240 Noncurrent (e) 900 554 28 (90 ) 1,392 920 533 33 (51 ) 1,435 Total Assets $ 1,059 $ 779 $ 106 $ (448 ) $ 1,496 $ 1,502 $ 1,037 $ 142 $ (1,006 ) $ 1,675 Liabilities: Current $ (160 ) $ (198 ) $ (61 ) $ 363 $ (56 ) $ (572 ) $ (357 ) $ (112 ) $ 964 $ (77 ) Noncurrent (48 ) (62 ) (22 ) 105 (27 ) (38 ) (25 ) (6 ) 61 (8 ) Total Liabilities $ (208 ) $ (260 ) $ (83 ) $ 468 $ (83 ) $ (610 ) $ (382 ) $ (118 ) $ 1,025 $ (85 ) Net Assets (Liabilities) at the end of the period $ 851 $ 519 $ 23 $ 20 $ 1,413 $ 892 $ 655 $ 24 $ 19 $ 1,590 _______________________________________ (a) Amounts represent the impact of master netting agreements that allow DTE Energy to net gain and loss positions and cash collateral held or placed with the same counterparties. (b) At September 30, 2015 , available-for-sale securities of $14 million included $6 million and $8 million of cash equivalents included in Restricted cash and Other investments on DTE Energy's Consolidated Statements of Financial Position, respectively. 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 DTE Energy's Consolidated Statements of Financial Position, respectively. (c) Excludes cash surrender value of life insurance investments. (d) Primarily includes foreign currency exchange contracts. (e) Includes $145 million and $150 million at September 30, 2015 and December 31, 2014 , respectively, of other investments that are included in DTE Energy's Consolidated Statements of Financial Position in Other investments. The following table presents assets for DTE Electric measured and recorded at fair value on a recurring basis as of September 30, 2015 and December 31, 2014 : September 30, 2015 December 31, 2014 Level 1 Level 2 Level 3 Net Balance Level 1 Level 2 Level 3 Net Balance (In millions) Assets: Cash equivalents (a) $ 5 $ 3 $ — $ 8 $ 5 $ 99 $ — $ 104 Nuclear decommissioning trusts 742 457 — 1,199 792 449 — 1,241 Other investments 7 — — 7 97 50 — 147 Derivative assets — FTRs — — 5 5 — — 3 3 Total $ 754 $ 460 $ 5 $ 1,219 $ 894 $ 598 $ 3 $ 1,495 Assets: Current $ 5 $ 3 $ 5 $ 13 $ 5 $ 99 $ 3 $ 107 Noncurrent 749 457 — 1,206 889 499 — 1,388 Total Assets $ 754 $ 460 $ 5 $ 1,219 $ 894 $ 598 $ 3 $ 1,495 _______________________________________ (a) At September 30, 2015 , available-for-sale securities of $8 million consisted of cash equivalents included in Other investments on DTE Electric's Consolidated Statements of Financial Position. At December 31, 2014 , available-for-sale securities of $104 million included $96 million and $8 million of cash equivalents included in Restricted cash and Other investments, respectively, on DTE Electric's Consolidated Statements of Financial Position. 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. The Registrants have obtained an understanding of how these prices are derived, including the nature and observability of the inputs used in deriving such prices. Additionally, the Registrants selectively corroborate the fair value of securities by comparison of market-based price sources. Investment policies and procedures are determined by DTE Energy's Trust Investments Department which reports to DTE Energy'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. The Registrants consider 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. The Registrants monitor 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. The Registrants have obtained an understanding of how these prices are derived. Additionally, the Registrants selectively corroborate the fair value of their 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 Registrants have 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 the Registrants' forward price curves has been assigned to DTE Energy's Risk Management Department, which is separate and distinct from the trading functions within DTE Energy. The following tables present the fair value reconciliation of Level 3 assets and liabilities measured at fair value on a recurring basis for DTE Energy for the three and nine months ended September 30, 2015 and 2014 : Three Months Ended September 30, 2015 Three Months Ended September 30, 2014 Natural Gas Electricity Other Total Natural Gas Electricity Other Total (In millions) Net Assets (Liabilities) as of June 30 $ (8 ) $ 3 $ 1 $ (4 ) $ (20 ) $ (27 ) $ 7 $ (40 ) Transfers into Level 3 from Level 2 — — — — 1 — — 1 Transfers from Level 3 into Level 2 — — — — (4 ) — — (4 ) Total gains (losses): Included in earnings 24 18 (3 ) 39 (2 ) 13 (1 ) 10 Recorded in regulatory assets/liabilities — — 3 3 — — (3 ) (3 ) Purchases, issuances, and settlements: Purchases — — — — — — — — Issuances — — — — — — — — Settlements 5 (18 ) (2 ) (15 ) (3 ) (3 ) — (6 ) Net Assets (Liabilities) as of September 30 $ 21 $ 3 $ (1 ) $ 23 $ (28 ) $ (17 ) $ 3 $ (42 ) 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 September 30, 2015 and 2014 and reflected in Operating revenues and Fuel, purchased power and gas in DTE Energy's Consolidated Statements of Operations $ 18 $ (3 ) $ (3 ) $ 12 $ (7 ) $ 14 $ (1 ) $ 6 Nine Months Ended September 30, 2015 Nine Months Ended September 30, 2014 Natural Gas Electricity Other Total Natural Gas Electricity Other Total (In millions) Net Assets (Liabilities) as of December 31 $ 30 $ (5 ) $ (1 ) $ 24 $ (52 ) $ 13 $ 3 $ (36 ) Transfers into Level 3 from Level 2 — — — — — — — — Transfers from Level 3 into Level 2 — — — — 2 — — 2 Total gains (losses): Included in earnings (11 ) 42 (5 ) 26 (45 ) 26 (2 ) (21 ) Recorded in regulatory assets/liabilities — — 14 14 — — 9 9 Purchases, issuances, and settlements: Purchases — 2 — 2 — 1 — 1 Issuances — — — — — (2 ) — (2 ) Settlements 2 (36 ) (9 ) (43 ) 67 (55 ) (7 ) 5 Net Assets (Liabilities) as of September 30 $ 21 $ 3 $ (1 ) $ 23 $ (28 ) $ (17 ) $ 3 $ (42 ) 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 September 30, 2015 and 2014 and reflected in Operating revenues and Fuel, purchased power and gas in DTE Energy's Consolidated Statements of Operations $ (94 ) $ 8 $ (4 ) $ (90 ) $ (23 ) $ (6 ) $ (1 ) $ (30 ) The following table presents the fair value reconciliation of Level 3 assets and liabilities measured at fair value on a recurring basis for DTE Electric for the three and nine months ended September 30, 2015 and 2014 : Three Months Ended September 30, Nine Months Ended September 30, 2015 2014 2015 2014 (In millions) Net Assets as of beginning of period $ 5 $ 7 $ 3 $ 3 Change in fair value recorded in regulatory assets/liabilities 3 (3 ) 14 9 Purchases, issuances, and settlements: Settlements (3 ) — (12 ) (8 ) Net Assets as of September 30 $ 5 $ 4 $ 5 $ 4 The amount of total gains (losses) included in Regulatory assets and liabilities attributed to the change in unrealized gains (losses) related to assets and liabilities held at September 30, 2015 and 2014 and reflected in DTE Electric's Consolidated Statements of Financial Position $ 1 $ (1 ) $ 5 $ 4 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 for the Registrants during the three and nine months ended September 30, 2015 and 2014 , and there were no transfers from or into Level 3 for DTE Electric during the same periods. The following table presents the unobservable inputs related to DTE Energy's Level 3 assets and liabilities as of September 30, 2015 : September 30, 2015 Commodity Contracts Derivative Assets Derivative Liabilities Valuation Techniques Unobservable Input Range Weighted Average (In millions) Natural Gas $ 54 $ (33 ) Discounted Cash Flow Forward basis price (per MMBtu) $ (1.73 ) — $ 6.57 /MMBtu $ (0.11 )/MMBtu Electricity $ 47 $ (44 ) Discounted Cash Flow Forward basis price (per MWh) $ (8 ) — $ 15 /MWh $ 1 /MWh The following table presents the unobservable inputs related to DTE Energy's Level 3 assets and liabilities as of December 31, 2014 : 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 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. The Registrants have obtained an understanding of how the fair values are derived. The Registrants also selectively corroborate the fair value of their 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 for the Registrants are determined by DTE Energy's Treasury Department which reports to DTE Energy's Vice President and Treasurer. The following table presents the carrying amount and fair value of financial instruments for DTE Energy as of September 30, 2015 and December 31, 2014 : September 30, 2015 December 31, 2014 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 $ 34 $ — $ — $ 34 $ 41 $ — $ — $ 41 Dividends payable $ 131 $ 131 $ — $ — $ 122 $ 122 $ — $ — Short-term borrowings $ 185 $ — $ 185 $ — $ 398 $ — $ 398 $ — Long-term debt, excluding capital leases $ 9,310 $ 480 $ 8,289 $ 1,186 $ 8,606 $ 489 $ 8,308 $ 706 The following table presents the carrying amount and fair value of financial instruments for DTE Electric as of September 30, 2015 and December 31, 2014 : September 30, 2015 December 31, 2014 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 $ 6 $ — $ — $ 6 $ 12 $ — $ — $ 12 Notes receivable — affiliates $ 4 $ — $ — $ 4 $ 8 $ — $ — $ 8 Short-term borrowings — affiliates $ 68 $ — $ — $ 68 $ 84 $ — $ — $ 84 Short-term borrowings — other $ 46 $ — $ 46 $ — 50 $ — $ 50 $ — Long-term debt, excluding capital leases $ 5,644 $ — $ 5,496 $ 562 $ 5,259 $ — $ 5,341 $ 496 For further fair value information on financial and derivative instruments see Note 9 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 ARO on the Registrants' 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 5 to the Consolidated Financial Statements, " Asset Retirement Obligations ". The following table summarizes DTE Electric's fair value of the nuclear decommissioning trust fund assets: September 30, 2015 December 31, 2014 (In millions) Fermi 2 $ 1,175 $ 1,221 Fermi 1 3 3 Low-level radioactive waste 21 17 Total $ 1,199 $ 1,241 The costs of securities sold are determined on the basis of specific identification. The following table sets forth DTE Electric's gains and losses and proceeds from the sale of securities by the nuclear decommissioning trust funds: Three Months Ended September 30, Nine Months Ended September 30, 2015 2014 2015 2014 (In millions) Realized gains $ 8 $ 8 $ 30 $ 24 Realized losses $ (10 ) $ (3 ) $ (23 ) $ (14 ) Proceeds from sales of securities $ 187 $ 177 $ 627 $ 652 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 DTE Electric's fair value and unrealized gains and losses for the nuclear decommissioning trust funds: September 30, 2015 December 31, 2014 Fair Unrealized Unrealized Fair Unrealized Unrealized (In millions) Equity securities $ 708 $ 169 $ (74 ) $ 756 $ 204 $ (39 ) Debt securities 484 18 (2 ) 474 21 (2 ) Cash and cash equivalents 7 — — 11 — — $ 1,199 $ 187 $ (76 ) $ 1,241 $ 225 $ (41 ) The debt securities at September 30, 2015 and December 31, 2014 had an average maturity of approximately 6 and 7 years , respectively. 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 September 30, 2015 and December 31, 2014 , the Registrants' securities were comprised primarily of money market and equity securities. There were no unrealized losses on available-for-sale securities which were reclassified out of Other comprehensive income and realized into Net Income for DTE Energy or DTE Electric during the three and nine months ended September 30, 2015 and 2014 . Losses related to trading securities held at September 30, 2015 were $2 million and gains related to trading securities held at September 30, 2014 were $9 million , respectively, for DTE Energy, including $2 million of losses and $8 million of gains, respectively, relating to DTE Electric. The trading gains or losses related to the Rabbi Trust assets are allocated from DTE Energy to DTE Electric.

Financial and Other Derivative

Financial and Other Derivative Instruments	9 Months Ended
	Sep. 30, 2015
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Financial and Other Derivative Instruments	FINANCIAL AND OTHER DERIVATIVE INSTRUMENTS The Registrants recognize all derivatives at their fair value as Derivative assets or liabilities on their respective 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 fair value are recognized in earnings each period. The Registrants’ primary market risk exposure is associated with commodity prices, credit, and interest rates. The Registrants have risk management policies to monitor and manage market risks. The Registrants use derivative instruments to manage some of the exposure. DTE Energy uses derivative instruments for trading purposes in its Energy Trading segment. Contracts classified as derivative instruments include electricity, natural gas, oil, 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 normal sales exception 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 2018. Substantially all of these contracts meet the normal purchases and normal sales exception 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. DTE Energy 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 — DTE Energy may use interest rate swaps, treasury locks, and other derivatives to hedge the risk associated with interest rate market volatility. Credit Risk — DTE Energy 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. DTE Energy generally uses standardized agreements that allow the netting of positive and negative transactions associated with a single counterparty. DTE Energy maintains a provision for credit losses based on factors surrounding the credit risk of its customers, historical trends, and other information. Based on DTE Energy's credit policies and its September 30, 2015 provision for credit losses, DTE Energy’s exposure to counterparty nonperformance is not expected to have a material adverse effect on DTE Energy's Consolidated Financial Statements. Derivative Activities DTE Energy 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 table presents the fair value of derivative instruments as of September 30, 2015 and December 31, 2014 for DTE Energy: September 30, 2015 December 31, 2014 Derivative Assets Derivative Liabilities Derivative Assets Derivative Liabilities (In millions) Derivatives not designated as hedging instruments: Foreign currency exchange contracts $ 10 $ (7 ) $ 4 $ (5 ) Commodity Contracts: Natural Gas 303 (277 ) 787 (718 ) Electricity 251 (244 ) 342 (342 ) Other 22 (23 ) 45 (45 ) Total derivatives not designated as hedging instruments: $ 586 $ (551 ) $ 1,178 $ (1,110 ) Total derivatives: Current $ 448 $ (419 ) $ 1,083 $ (1,041 ) Noncurrent 138 (132 ) 95 (69 ) Total derivatives $ 586 $ (551 ) $ 1,178 $ (1,110 ) The following table presents the fair value of derivative instruments as of September 30, 2015 and December 31, 2014 for DTE Electric: September 30, 2015 December 31, 2014 (In millions) FTRs — Other current assets $ 5 $ 3 Total derivatives not designated as hedging instrument $ 5 $ 3 Certain of DTE Energy'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, DTE Energy offsets the fair value of derivative instruments with cash collateral received or paid for those contracts executed with the same counterparty, which reduces DTE Energy'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. DTE Energy 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. DTE Energy had no letters of credit outstanding at September 30, 2015 and $7 million in letters of credit at December 31, 2014 , which could be used to offset net derivative liabilities. Letters of credit received from third parties which could be used to offset net derivative assets were $1 million and $5 million at September 30, 2015 and December 31, 2014 , respectively. Such balances of letters of credit are excluded from the tables below and are not netted with the recognized assets and liabilities in DTE Energy's 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 DTE Energy's 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. For DTE Energy, the total cash collateral posted, net of cash collateral received, was $27 million and $61 million as of September 30, 2015 and December 31, 2014 , respectively. As of September 30, 2015 , derivative assets and derivative liabilities are shown net of cash collateral of $1 million and $21 million , respectively. As of December 31, 2014 , 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 . DTE Energy recorded cash collateral paid of $8 million and cash collateral received of $1 million not related to unrealized derivative positions as of September 30, 2015 . DTE Energy 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 . 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 for DTE Energy at September 30, 2015 and December 31, 2014 : September 30, 2015 December 31, 2014 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 $ 303 $ (244 ) $ 59 $ 787 $ (681 ) $ 106 Electricity 251 (179 ) 72 342 (280 ) 62 Other 22 (17 ) 5 45 (42 ) 3 Other derivative contracts (a) 10 (8 ) 2 4 (3 ) 1 Total derivative assets $ 586 $ (448 ) $ 138 $ 1,178 $ (1,006 ) $ 172 Derivative liabilities: Commodity Contracts: Natural Gas $ (277 ) $ 249 $ (28 ) $ (718 ) $ 679 $ (39 ) Electricity (244 ) 190 (54 ) (342 ) 298 (44 ) Other (23 ) 22 (1 ) (45 ) 45 — Other derivative contracts (a) (7 ) 7 — (5 ) 3 (2 ) Total derivative liabilities $ (551 ) $ 468 $ (83 ) $ (1,110 ) $ 1,025 $ (85 ) _______________________________________ (a) Primarily includes foreign currency exchange contracts. The following table presents the netting offsets of derivative assets and liabilities showing the reconciliation of derivative instruments to DTE Energy's Consolidated Statements of Financial Position at September 30, 2015 and December 31, 2014 : September 30, 2015 December 31, 2014 Derivative Assets Derivative Liabilities Derivative Assets Derivative Liabilities Current Noncurrent Current Noncurrent Current Noncurrent Current Noncurrent (In millions) Total fair value of derivatives $ 448 $ 138 $ (419 ) $ (132 ) $ 1,083 $ 95 $ (1,041 ) $ (69 ) Counterparty netting (358 ) (89 ) 358 89 (955 ) (51 ) 955 51 Collateral adjustment — (1 ) 5 16 — — 9 10 Total derivatives as reported $ 90 $ 48 $ (56 ) $ (27 ) $ 128 $ 44 $ (77 ) $ (8 ) The effect of derivatives not designated as hedging instruments on DTE Energy's Consolidated Statements of Operations for the three and nine months ended September 30, 2015 and 2014 for DTE Energy is as follows: Derivatives not Designated as Hedging Instruments Location of Gain Gain (Loss) Recognized in Income on Derivatives for the Three Months Ended September 30, Gain (Loss) Recognized in Income on Derivatives for the Nine Months Ended September 30, 2015 2014 2015 2014 (In millions) Foreign currency exchange contracts Operating Revenue $ 1 $ (1 ) $ 2 $ (2 ) Commodity Contracts: Natural Gas Operating Revenue 55 (38 ) (75 ) (10 ) Natural Gas Fuel, purchased power, and gas (24 ) 12 9 23 Electricity Operating Revenue 14 12 60 100 Other Operating Revenue (4 ) (1 ) (4 ) (5 ) Total $ 42 $ (16 ) $ (8 ) $ 106 Revenues and energy costs related to trading contracts are presented on a net basis in DTE Energy's 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 DTE Energy's derivative contracts outstanding as of September 30, 2015 : Commodity Number of Units Natural Gas (MMBtu) 1,083,436,935 Electricity (MWh) 22,421,752 Oil (Gallons) 23,520,000 Foreign Currency Exchange (Canadian dollars) 42,420,220 Various subsidiaries of DTE Energy 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 DTE Energy 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 DTE Energy 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 DTE Energy 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 September 30, 2015 , DTE Energy's contractual obligation to post collateral in the form of cash or letters of credit in the event of a downgrade to below investment grade, under both hard trigger and soft trigger provisions, was approximately $420 million . As of September 30, 2015 , DTE Energy had approximately $516 million of derivatives in net liability positions, for which hard triggers exist. There is no collateral that has been posted against such liabilities, including cash and letters of credit. Associated derivative net asset positions for which contractual offset exists were approximately $430 million . The net remaining amount of approximately $85 million is derived from the $420 million noted above.

Long-Term Debt

Long-Term Debt	9 Months Ended
	Sep. 30, 2015
Long-term Debt, Unclassified [Abstract]
Long-term Debt	LONG-TERM DEBT Debt Issuances In 2015 , the following debt was issued: Company Month Type Interest Rate Maturity Amount (In millions) DTE Electric March Mortgage Bonds (a) 3.70% 2045 $ 500 DTE Energy June Senior Notes (b) 3.30% 2022 300 DTE Gas August Mortgage Bonds (c) 3.35% 2027 40 DTE Gas August Mortgage Bonds (c) 4.21% 2045 125 $ 965 _______________________________________ (a) Proceeds were used for the redemption of long-term debt, for the repayment of short-term borrowings, and for general corporate purposes. (b) Proceeds were used for general corporate purposes. (c) Proceeds were used for the redemption of long-term debt and for general corporate purposes. Debt Redemptions In 2015 , the following debt was redeemed: Company Month Type Interest Rate Maturity Amount (In millions) DTE Electric March Securitization Bonds 6.62% 2015 $ 105 DTE Electric March Mortgage Bonds 7.904% 2016 10 DTE Gas September Senior Notes 5.94% 2015 140 DTE Energy Various Other Long Term Debt Various 2015 5 $ 260

Short-Term Credit Arrangements

Short-Term Credit Arrangements and Borrowings	9 Months Ended
	Sep. 30, 2015
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. In August 2015, the DTE Energy unsecured letter of credit facility expired. In September 2015, DTE Energy entered into a new, $70 million , two year unsecured letter of credit facility. The facility has the same financial covenants as DTE Energy's unsecured revolving credit facilities. The agreements require DTE Energy, DTE Electric, and DTE Gas to maintain a total funded debt to capitalization ratio of no more than 0.65 to 1. In the agreements, “total funded debt” means all indebtedness of each respective company and their consolidated subsidiaries, including capital lease obligations, hedge agreements, and guarantees of third parties’ debt, but excluding contingent obligations, nonrecourse and junior subordinated debt, and certain equity-linked securities and, except for calculations at the end of the second quarter, certain DTE Gas short-term debt. “Capitalization” means the sum of (a) total funded debt plus (b) “consolidated net worth”, which is equal to consolidated total stockholders’ equity of each respective company and their consolidated subsidiaries (excluding pension effects under certain FASB statements), as determined in accordance with accounting principles generally accepted in the United States of America. At September 30, 2015 , the total funded debt to total capitalization ratios for DTE Energy, DTE Electric, and DTE Gas were 0.50 to 1, 0.50 to 1, and 0.48 to 1, respectively, and are in compliance with this financial covenant. The availability under the facilities in place at September 30, 2015 is shown in the following table: DTE Energy DTE Electric DTE Gas Total (In millions) Unsecured letter of credit facility, expiring in February 2017 $ 100 $ — $ — $ 100 Unsecured letter of credit facility, expiring in September 2017 70 — — 70 Unsecured revolving credit facility, expiring April 2020 1,200 400 300 1,900 1,370 400 300 2,070 Amounts outstanding at September 30, 2015: Commercial paper issuances 11 46 128 185 Letters of credit 185 — — 185 196 46 128 370 Net availability at September 30, 2015 $ 1,174 $ 354 $ 172 $ 1,700 DTE Energy has other outstanding letters of credit which are not included in the above described facilities totaling approximately $20 million which are used for various corporate purposes. In conjunction with maintaining certain exchange traded risk management positions, DTE Energy may be required to post cash collateral with its clearing agent. DTE Energy 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 DTE Energy posts a letter of credit for the incremental amount. At September 30, 2015 , a $25 million letter of credit was in place, raising the capacity under this facility to $125 million . The $25 million letter of credit is included in the table above. The amount outstanding under this agreement was $70 million and $37 million at September 30, 2015 and December 31, 2014 , respectively.

Commitments and Contingencies

Commitments and Contingencies	9 Months Ended
	Sep. 30, 2015
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	COMMITMENTS AND CONTINGENCIES Environmental DTE 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. Additional rulemakings are expected over the next few years which could require additional controls for sulfur dioxide, nitrogen oxides and hazardous air pollutants. The Cross State Air Pollution Rule (CSAPR), required further reductions of sulfur dioxide and nitrogen oxides emissions beginning in January 2015. DTE Electric expects to meet its obligations under CSAPR. However, portions of CSAPR are being reviewed by the Court of Appeals for the D.C. District and any financial impact related to this review cannot be predicted at this time. The Mercury and Air Toxics Standards (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. DTE Electric has requested and been granted compliance date extensions for all relevant units to April 2016. DTE Electric has tested several technologies as MATS compliance alternatives to Flue Gas Desulfurization (FGD) systems to determine technological and economic feasibility. Dry Sorbent Injection (DSI) and Activated Carbon Injection (ACI) technologies were deemed feasible and their implementation will allow units that would not have been economical for FGD installations to continue operation in compliance with MATS. In November 2014, the U.S. 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. In June 2015, the U.S. Supreme Court reversed the decision of the Court of Appeals for the D.C. District and remanded the MATS rule to the Court of Appeals for further consideration based on their decision that the EPA must consider costs prior to deciding to regulate under the provisions of the Clean Air Act. DTE Electric does not expect this decision to have a material effect on its compliance plans at this time. The EPA proposed revised air quality standards for ground level ozone in November 2014 and specifically requested comments on the form and level of the ozone standards. The standards were finalized on October 1, 2015. DTE Electric cannot predict the financial impact of the revised 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 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 Power Plant 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. The amended New Source Review claims are all stayed until the appeal is resolved by the Court of Appeals for the Sixth Circuit. Oral arguments for the appeal are scheduled for December 2015. The Registrants 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 Registrants cannot predict the financial impact or outcome of this matter, or the timing of its resolution. To comply with air pollution requirements, DTE Electric spent approximately $2.2 billion through 2014 . DTE Electric estimates making capital expenditures of approximately $100 million in 2015 and approximately $50 million of additional capital expenditures in 2016 based on current regulations. 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 any required technology will be determined by each state on a case by case basis. DTE Electric is 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 were finalized on September 30, 2015 and are expected to be effective by the end of 2015. It is not possible at this time to quantify the impacts of the final rules. 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, DTE Electric 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 September 30, 2015 and December 31, 2014 , DTE Electric had $9 million and $10 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 DTE Electric’s financial position and cash flows. DTE Electric believes the likelihood of a material change to the accrued amount is remote based on current knowledge of the conditions at each site. Coal Combustion Residual Rule — In April 2015, the EPA published a final rule for the disposal of coal combustion residuals, commonly known as coal ash. The rule becomes effective in October 2015. The rule is based on the continued listing of coal ash as a non-hazardous waste and relies on various self-implementation design and performance standards. DTE Electric owns and operates three permitted engineered coal ash storage facilities to dispose of coal ash from coal-fired power plants and operates a number of smaller impoundments at its power plants. At certain facilities, the rule requires the installation of monitoring wells, compliance with groundwater standards and the closure of basins at the end of the useful life of the associated power plant. At other facilities, the rule requires ash laden waters be moved from earthen basins to steel and concrete tanks. Costs associated with the building of new facilities over the next seven years are estimated to be approximately $190 million . See Note 5 to the Consolidated Financial Statements, " Asset Retirement Obligations ", for estimated costs of closure of old facilities. DTE Gas Contaminated and Other Sites — DTE Gas owns or previously owned, 14 former MGP sites. Investigations have revealed contamination related to the by-products of gas manufacturing at each site. Cleanup of five of the MGP sites is complete and the sites are closed. DTE Gas has also completed partial closure of two additional sites. Cleanup activities associated with the remaining sites will continue 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, DTE Gas is also in the process of cleaning up other contaminated sites, including gate stations, gas pipeline releases and underground storage tank locations. As of September 30, 2015 and December 31, 2014 , DTE Gas had $23 million and $24 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 DTE Gas’s financial position and cash flows. DTE Gas anticipates the cost amortization methodology approved by the MPSC, which allows for amortization of 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 DTE Gas’s results of operations. Non-utility DTE Energy’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 DTE Energy’s position of demonstrated compliance and has not initiated escalated enforcement. At this time, DTE Energy 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 DTE Energy self reporting to MDEQ questionable activities by an employee of a contractor hired by DTE Energy to perform the visible emissions readings. At this time, DTE Energy cannot predict the impact of this investigation. DTE Energy 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. DTE Energy settled the alleged violations by implementing best management practices to address the issues and repair/upgrade their wastewater treatment plant. DTE Energy received a construction 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 biological treatment. DTE Energy spent approximately $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. DTE Energy expects to also spend up to an additional $15 million over the next few years to complete its upgrade of the treatment technology to biological treatment in order to meet future regulatory requirements and gain other operational improvement savings. DTE Energy received an NOV from the Allegheny County (PA) Health Department pertaining to excessive opacity readings from fugitive sources in excess of its standards for the Pennsylvania coke battery facility. Fugitive sources at the plant are in full compliance with the applicable Federal Opacity Standards. DTE Energy agreed to a Consent Order and Agreement with Allegheny County pursuant to which DTE Energy paid a fine of $300,000 and will spend $300,000 for a supplemental environmental project. In May 2014, the Group Against Smog & Pollution (GASP) filed a complaint alleging that DTE Energy's coke battery facility in Pennsylvania was in violation of visible emissions limits under the Federal Clean Air Act and/or Article XXI of the Allegheny County (PA) Health Department's Rules and Regulations. DTE Energy believed that the GASP suit was without merit and filed a motion to dismiss in July 2014. In March 2015, the U.S. District Court granted DTE Energy's motion for dismissal. In April 2015, GASP filed a notice of appeal. At the present time, DTE Energy cannot predict the financial impact or outcome of this matter, or the timing of its resolution. 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 2018. Michigan's non-attainment area includes DTE Energy facilities in southwest Detroit and areas of Wayne County. 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 DTE Energy's Michigan coke battery facility. As part of the state implementation plan process, DTE Energy has worked with MDEQ to develop air permits reflecting significant SO2 emission reductions that, in combination with other non-DTE Energy sources emission reduction startegies, will help the State attain the standard and sustain its attainment. Since several non-DTE Energy sources are also part of the proposed compliance plan, DTE Energy is unable to determine the full impact of the final 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 . 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 $46 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 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 DTE Energy discontinued the operations of its synthetic fuel production facilities throughout the United States as of December 31, 2007. DTE Energy 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. DTE Energy estimates that its maximum potential liability under these guarantees at September 30, 2015 is approximately $850 million . Payment under these guarantees is considered remote. REF Guarantees DTE Energy has provided certain guarantees and indemnities in conjunction with the sales of interests in or lease of 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. DTE Energy estimates that its maximum potential liability under these guarantees at September 30, 2015 is approximately $238 million . Payment under these guarantees is considered remote. Other Guarantees In certain limited circumstances, the Registrants enter into contractual guarantees. The Registrants may guarantee another entity’s obligation in the event it fails to perform and may provide guarantees in certain indemnification agreements. Finally, the Registrants may provide indirect guarantees for the indebtedness of others. DTE Energy’s guarantees are not individually material with maximum potential payments totaling $66 million at September 30, 2015 . Payment under these guarantees is considered remote. DTE Energy 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 September 30, 2015 , DTE Energy had approximately $49 million of performance bonds outstanding. In the event that such bonds are called for nonperformance, DTE Energy would be obligated to reimburse the issuer of the performance bond. DTE Energy 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 DTE Energy's approximately 4,900 represented employees, including DTE Electric's approximately 2,600 represented employees. The majority of the represented employees are under contracts that expire in 2016 and 2017. Purchase Commitments As of September 30, 2015 , the Registrants were party to numerous long-term purchase commitments relating to a variety of goods and services required for their businesses. These agreements primarily consist of fuel supply commitments and renewable energy contracts for the Registrants, as well as energy trading contracts for DTE Energy. DTE Energy estimates that these commitments will be approximately $7.4 billion from 2015 through 2051 . DTE Electric estimates that these commitments will be approximately $2.2 billion from 2015 through 2033 . In addition, the Registrants have made certain commitments in connection with 2015 annual capital expenditures and contributions to equity method investees that are expected to be up to $2.5 billion for DTE Energy and $1.8 billion for DTE Electric. Bankruptcies Certain of the Registrants' customers and suppliers have filed for bankruptcy protection under the U.S. Bankruptcy Code. The Registrants regularly review contingent matters relating to these customers and suppliers and their purchase and sale contracts and record provisions for amounts considered at risk of probable loss. The Registrants believe their accrued amounts are adequate for probable loss. Michigan Sales and Use Tax Litigation In 2010, the Michigan Department of Treasury finalized a sales and use tax audit of DTE Electric for the period from January 2003 to September 2006. It determined that DTE Electric’s electric distribution equipment was not eligible for an industrial-processing exemption and therefore was subject to the use tax. DTE Electric paid the tax for the period under audit and filed a claim in the Michigan Court of Claims disputing the tax determination. DTE Electric has continued to apply the industrial-processing exemption for the years subsequent to 2006. The Michigan Court of Claims found in favor of DTE Electric, and that determination was subsequently appealed to the Michigan Supreme Court. In July 2015, the Michigan Supreme Court issued an opinion finding that DTE Electric was eligible for a partial industrial-processing exemption on its electric distribution equipment based on the proportion of exempt use of that equipment. The Supreme Court reversed the lower court decision in part and remanded the case to the Michigan Court of Claims. DTE Electric expects this issue and the timing of any potential tax refunds or assessments to be resolved not later than 2016. DTE Electric considers the likelihood of a material unfavorable outcome to be remote. Other Contingencies The Registrants are 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 Registrants cannot predict the final disposition of such proceedings. The Registrants regularly review legal matters and record provisions for claims that they can estimate and are considered probable of loss. The resolution of these pending proceedings is not expected to have a material effect on the Registrants' operations or financial statements in the periods they are resolved. For a discussion of contingencies related to regulatory matters and derivatives see Notes 6 and 9 to the Consolidated Financial Statements, " Regulatory Matters " and " Financial and Other Derivative Instruments ", respectively.

Retirement Benefits and Trustee

Retirement Benefits and Trusteed Assets	9 Months Ended
	Sep. 30, 2015
Defined Benefit Pension Plans and Defined Benefit Postretirement Plans Disclosure [Abstract]
Retirement Benefits and Trusteed Assets	RETIREMENT BENEFITS AND TRUSTEED ASSETS The following table details the components of net periodic benefit costs for pension benefits and other postretirement benefits for DTE Energy: Pension Benefits Other Postretirement Benefits 2015 2014 2015 2014 Three Months Ended September 30, (In millions) Service cost $ 27 $ 19 $ 8 $ 8 Interest cost 52 54 20 22 Expected return on plan assets (74 ) (69 ) (33 ) (31 ) Amortization of: Net actuarial loss 51 42 10 4 Prior service credit — — (31 ) (36 ) Net periodic benefit cost (credit) $ 56 $ 46 $ (26 ) $ (33 ) Pension Benefits Other Postretirement Benefits 2015 2014 2015 2014 Nine Months Ended September 30, (In millions) Service cost $ 76 $ 62 $ 25 $ 26 Interest cost 158 159 61 67 Expected return on plan assets (222 ) (205 ) (98 ) (92 ) Amortization of: Net actuarial loss 154 118 32 15 Prior service credit — — (94 ) (108 ) Net periodic benefit cost (credit) $ 166 $ 134 $ (74 ) $ (92 ) The following table details the components of net periodic benefit costs for pension benefits and other postretirement benefits for DTE Electric: Pension Benefits Other Postretirement Benefits 2015 2014 2015 2014 Three Months Ended September 30, (In millions) Service cost $ 21 $ 14 $ 6 $ 6 Interest cost 39 41 15 17 Expected return on plan assets (53 ) (48 ) (23 ) (21 ) Amortization of: Net actuarial loss 36 30 8 3 Prior service credit — — (24 ) (27 ) Net periodic benefit cost (credit) $ 43 $ 37 $ (18 ) $ (22 ) Pension Benefits Other Postretirement Benefits 2015 2014 2015 2014 Nine Months Ended September 30, (In millions) Service cost $ 59 $ 48 $ 19 $ 19 Interest cost 120 121 46 51 Expected return on plan assets (158 ) (145 ) (68 ) (63 ) Amortization of: Net actuarial loss 110 83 24 11 Prior service cost (credit) 1 1 (71 ) (82 ) Net periodic benefit cost (credit) $ 132 $ 108 $ (50 ) $ (64 ) Pension and Other Postretirement Contributions During the first nine months of 2015 , DTE Energy made cash contributions of $175 million , including contributions from DTE Electric of $145 million , to its pension plans. During 2015 , DTE Energy contributed the following amounts of DTE Energy common stock to the DTE Energy Company Master VEBA Trust for funding its other postretirement benefit plans: Date Number of Shares Price per Share Amount (In millions) February 17, 2015 1,427,835 $81.91 $ 117 $ 117 The above contribution was made on behalf of DTE Electric, who paid DTE Energy cash consideration of $117 million in February 2015. During 2015 , DTE Energy also made cash contributions of $24 million , through contributions from DTE Gas, to the Master VEBA Trust for its other postretirement benefit plans. At the discretion of management, DTE Energy may make up to $60 million of additional contributions from DTE Electric to its other postretirement benefit plans in 2015 . Plan Changes In 2015, certain executive retirement benefit plans were amended to transfer the obligation for benefits as attributed to DTE Energy Corporate Services, LLC (LLC), a subsidiary of DTE Energy. The related plan liabilities were transferred from DTE Electric and DTE Gas to LLC. The related Rabbi Trust assets were also transferred to DTE Energy from DTE Electric.

Stock-Based Compensation

Stock-Based Compensation	9 Months Ended
	Sep. 30, 2015
Share-based Compensation [Abstract]
Stock-based Compensation	STOCK-BASED COMPENSATION The following table summarizes the components of stock-based compensation for DTE Energy: Three Months Ended September 30, Nine Months Ended September 30, 2015 2014 2015 2014 (In millions) Stock-based compensation expense $ 12 $ 22 $ 32 $ 72 Tax benefit $ 5 $ 8 $ 13 $ 27 Stock-based compensation cost capitalized in Property, plant, and equipment $ 2 $ 4 $ 5 $ 11 Stock Options The following table summarizes DTE Energy's stock option activity for the nine months ended September 30, 2015 : Number of Weighted Aggregate Intrinsic Value Options outstanding at December 31, 2014 444,278 $ 43.56 Exercised (178,017 ) $ 45.07 Forfeited or expired (3,979 ) $ 44.72 Options outstanding and exercisable at September 30, 2015 262,282 $ 42.52 $ 9 As of September 30, 2015 , the weighted average remaining contractual life for the exercisable shares is 3.05 years . As of September 30, 2015 , all options were vested. The intrinsic value of options exercised for the nine months ended September 30, 2015 and 2014 was $7 million for both periods. No option expense was recognized for the nine months ended September 30, 2015 and 2014, respectively . Restricted Stock Awards The following table summarizes DTE Energy’s restricted stock awards activity for the nine months ended September 30, 2015 : Restricted Weighted Average Grant Date Fair Value Balance at December 31, 2014 416,318 $ 62.82 Grants 143,800 $ 83.44 Forfeitures (8,975 ) $ 73.62 Vested and issued (158,920 ) $ 55.36 Balance at September 30, 2015 392,223 $ 73.15 Performance Share Awards Performance shares awarded under the plan are for a specified number of shares of DTE Energy common stock that entitle the holder to receive a cash payment, shares of DTE Energy 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 and 2015 were primarily deemed to be equity awards. The DTE Energy 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 following table summarizes DTE Energy’s performance share activity for the nine months ended September 30, 2015 : Performance Weighted Average Grant Date Fair Value Balance at December 31, 2014 1,554,697 $ 69.32 Grants 454,654 $ 83.86 Forfeitures (37,112 ) $ 75.90 Payouts (532,700 ) $ — Balance at September 30, 2015 1,439,539 $ 75.80 Unrecognized Compensation Costs As of September 30, 2015 , DTE Energy had $60 million of total unrecognized compensation cost related to non-vested stock incentive plan arrangements. That cost is expected to be recognized over a weighted-average period of 1.23 years . Allocated Stock-Based Compensation DTE Electric received an allocation of costs from DTE Energy associated with stock-based compensation of $7 million and $14 million for the three months ended September 30, 2015 and 2014 , respectively while such allocation was $20 million and $43 million for the nine months ended September 30, 2015 and 2014, respectively .

Segment and Related Information

Segment and Related Information	9 Months Ended
	Sep. 30, 2015
Segment Reporting [Abstract]
Segment and Related Information	SEGMENT AND RELATED INFORMATION DTE Energy 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 and 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 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: Three Months Ended September 30, Nine Months Ended September 30, 2015 2014 2015 2014 (In millions) Inter-segment Revenues Electric $ 9 $ 8 $ 27 $ 22 Gas 1 1 2 5 Gas Storage and Pipelines 1 1 7 9 Power and Industrial Projects 204 211 599 593 Energy Trading 7 8 23 24 Corporate and Other 1 1 2 2 $ 223 $ 230 $ 660 $ 655 Financial data of the DTE Energy business segments follows: Three Months Ended September 30, Nine Months Ended September 30, 2015 2014 2015 2014 (In millions) Operating Revenues Electric $ 1,386 $ 1,358 $ 3,737 $ 4,049 Gas 153 149 1,018 1,182 Gas Storage and Pipelines 61 49 175 146 Power and Industrial Projects 585 605 1,708 1,703 Energy Trading 635 664 1,870 2,797 Corporate and Other 1 — 2 1 Reconciliation and Eliminations (223 ) (230 ) (660 ) (655 ) Total $ 2,598 $ 2,595 $ 7,850 $ 9,223 Net Income (Loss) Attributable to DTE Energy by Segment: Electric $ 214 $ 135 $ 449 $ 400 Gas (11 ) (16 ) 93 109 Gas Storage and Pipelines 27 20 79 59 Power and Industrial Projects 32 38 73 66 Energy Trading 12 (22 ) — 6 Corporate and Other (9 ) 1 (47 ) (34 ) Net Income Attributable to DTE Energy Company $ 265 $ 156 $ 647 $ 606

Significant Accounting Polici24

Significant Accounting Policies (Policies)	9 Months Ended
	Sep. 30, 2015
Accounting Policies [Abstract]
Basis of Presentation	The accompanying Consolidated Financial Statements of the Registrants 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 Registrants' estimates.
Principles of Consolidation	The Registrants consolidate all majority-owned subsidiaries and investments in entities in which they have controlling influence. Non-majority owned investments are accounted for using the equity method when the Registrants are able to influence the operating policies of the investee. When the Registrants do not influence the operating policies of an investee, the cost method is used. These Consolidated Financial Statements also reflect the Registrants' proportionate interests in certain jointly-owned utility plants. The Registrants eliminate all intercompany balances and transactions. The Registrants evaluate whether an entity is a VIE whenever reconsideration events occur. The Registrants consolidate VIEs for which they are the primary beneficiary. If a Registrant 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, a Registrant 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 Registrants perform ongoing reassessments of all VIEs to determine if the primary beneficiary status has changed. Legal entities within DTE Energy'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 DTE Energy retaining operational and customer default risk. These entities generally are VIEs and consolidated when DTE Energy is the primary beneficiary. In addition, DTE Energy has interests in certain VIEs through which control of all significant activities is shared with partners, and therefore are accounted for under the equity method. DTE Energy has variable interests in VIEs through certain of its long-term purchase and sale contracts. DTE Electric has variable interests in VIEs through certain of its long-term purchase contracts. As of September 30, 2015 , the carrying amount of assets and liabilities in the Registrants' 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 Registrants for the deliveries associated with the current billing cycle under the contracts. The Registrants have 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 DTE Energy's variable interests through these long-term purchase and sale contracts. In addition, there is no significant potential exposure to loss as a result of DTE Electric's variable interests through these long-term purchase 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 performed servicing activities including billing and collecting surcharge revenue for Securitization. The remaining amounts due on the rate reduction bonds were paid in March 2015. The associated regulatory assets were fully amortized by March 31, 2015. Securitization has an over-recovery of funds. DTE Electric began to return the funds to customers in September 2015. Remaining funds are expected to be returned to customers during the fourth quarter of 2015 . Subsequent to the pay-down of the bonds, Securitization is no longer a VIE but continues to be consolidated by the Registrants as a voting interest entity. The maximum risk exposure for consolidated VIEs is reflected on the Registrants' 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.
Comprehensive Income	Changes in Accumulated other comprehensive income (loss) are presented in DTE Energy's Consolidated Statements of Changes in Equity and DTE Electric's Consolidated Statements of Changes in Shareholder's Equity.
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 businesses by the Registrants. DTE Energy amortizes contract intangible assets on a straight-line basis over the expected period of benefit, ranging from 1 to 26 years.
New Accounting Pronouncements	In May 2014, the FASB issued 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. In July 2015, the FASB deferred implementation of the revenue standard to be effective for the first interim period within annual reporting periods beginning after December 15, 2017. The standard is to be applied retrospectively and early adoption is permitted in the preceding year. The Registrants are currently assessing the impact of this ASU on their Consolidated Financial Statements. In February 2015, the FASB issued ASU No. 2015-02, Amendments to the Consolidation Analysis , which changes the analysis that a reporting entity must perform to determine whether it should consolidate certain types of legal entities. The ASU affects (1) limited partnerships and similar legal entities, (2) evaluating fees paid to a decision maker or a service provider as a variable interest, (3) the effect of fee arrangements on the primary beneficiary determination, (4) the effect of related parties on the primary beneficiary determination, and (5) certain investment funds. It is effective for the Registrants for the first interim period within annual reporting periods beginning on or after December 15, 2015 and early adoption is permitted. The Registrants are currently assessing the impact of this ASU on their Consolidated Financial Statements. In April 2015, the FASB issued ASU No. 2015-03, Simplifying the Presentation of Debt Issuance Costs . This ASU requires that debt issuance costs related to a recognized debt liability be presented in the balance sheet as a direct deduction from the carrying amount of that debt liability, consistent with debt discounts. This ASU is effective for reporting periods beginning after December 15, 2015 and interim periods therein. It is to be applied retrospectively and early adoption is permitted. The adoption of this ASU will not have a significant impact on the Registrants' Consolidated Statements of Financial Position. In July 2015, the FASB issued ASU No. 2015-11, Inventory (Topic 330), Simplifying the Measurement of Inventory . The ASU replaces the current lower of cost or market test with a lower of cost or net realizable value test when cost is determined on a first-in, first-out or average cost basis. The standard is effective for public entities for annual reporting periods beginning after December 15, 2016, and interim periods therein. It is to be applied prospectively and early adoption is permitted. The ASU will not have a significant impact on the Registrants' Consolidated Statements of Financial Position.
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 Registrants make certain assumptions they believe 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 Registrants and their counterparties is incorporated in the valuation of assets and liabilities through the use of credit reserves, the impact of which was immaterial at September 30, 2015 and December 31, 2014 . The Registrants believe they use 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 Registrants classify 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 Registrants have 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. The Registrants have obtained an understanding of how these prices are derived, including the nature and observability of the inputs used in deriving such prices. Additionally, the Registrants selectively corroborate the fair value of securities by comparison of market-based price sources. Investment policies and procedures are determined by DTE Energy's Trust Investments Department which reports to DTE Energy's Vice President and Treasurer.
Derivatives Reporting of Derivative Activity	The Registrants consider 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. The Registrants monitor 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. The Registrants have obtained an understanding of how these prices are derived. Additionally, the Registrants selectively corroborate the fair value of their 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 Registrants have 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 the Registrants' forward price curves has been assigned to DTE Energy's Risk Management Department, which is separate and distinct from the trading functions within DTE Energy.
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. The Registrants have obtained an understanding of how the fair values are derived. The Registrants also selectively corroborate the fair value of their 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 for the Registrants are determined by DTE Energy's Treasury Department which reports to DTE Energy's Vice President and Treasurer.
Derivatives	The Registrants recognize all derivatives at their fair value as Derivative assets or liabilities on their respective 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 fair value are recognized in earnings each period. The Registrants’ primary market risk exposure is associated with commodity prices, credit, and interest rates. The Registrants have risk management policies to monitor and manage market risks. The Registrants use derivative instruments to manage some of the exposure. DTE Energy uses derivative instruments for trading purposes in its Energy Trading segment. Contracts classified as derivative instruments include electricity, natural gas, oil, 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 DTE Energy'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, DTE Energy offsets the fair value of derivative instruments with cash collateral received or paid for those contracts executed with the same counterparty, which reduces DTE Energy'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. DTE Energy 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. DTE Energy had no letters of credit outstanding at September 30, 2015 and $7 million in letters of credit at December 31, 2014 , which could be used to offset net derivative liabilities. Letters of credit received from third parties which could be used to offset net derivative assets were $1 million and $5 million at September 30, 2015 and December 31, 2014 , respectively. Such balances of letters of credit are excluded from the tables below and are not netted with the recognized assets and liabilities in DTE Energy's 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 DTE Energy's 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 DTE Energy's 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.
Income Tax	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 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.

Organization and Basis of Pre25

Organization and Basis of Presentation (Tables)	9 Months Ended
	Sep. 30, 2015
Variable Interest Entity, Consolidated, Carrying Amount, Assets and Liabilities, Net [Abstract]
Schedule of Variable Interest Entities	The following table summarizes the major Consolidated Statements of Financial Position items for consolidated VIEs as of September 30, 2015 and December 31, 2014 . 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. Securitization, included in the DTE Energy table below for December 31, 2014 , also relates to DTE Electric. VIEs, in which DTE Energy 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. September 30, 2015 December 31, 2014 Total Securitization Other Total (In millions) ASSETS Cash and cash equivalents $ 12 $ — $ 7 $ 7 Restricted cash 6 96 8 104 Accounts receivable 14 26 15 41 Inventories 43 — 67 67 Property, plant, and equipment, net 70 — 81 81 Securitized regulatory assets — 34 — 34 Other current and long-term assets 4 1 6 7 $ 149 $ 157 $ 184 $ 341 LIABILITIES Accounts payable and accrued current liabilities $ 11 $ 3 $ 8 $ 11 Current portion long-term debt, including capital leases 9 105 10 115 Current regulatory liabilities — 32 — 32 Mortgage bonds, notes, and other 11 — 15 15 Capital lease obligations — — 3 3 Other current and long-term liabilities 6 9 6 15 $ 37 $ 149 $ 42 $ 191
Summary of Amounts for Non-Consolidated Variable Interest Entities	Amounts for DTE Energy's non-consolidated VIEs as of September 30, 2015 and December 31, 2014 are as follows: September 30, 2015 December 31, 2014 (In millions) Other investments $ 138 $ 134 Notes receivable $ 15 $ 15

Significant Accounting Polici26

Significant Accounting Policies (Tables)	9 Months Ended
	Sep. 30, 2015
Accounting Policies [Abstract]
Schedule of Finite-Lived Intangible Assets	DTE Energy has certain intangible assets relating to emission allowances, renewable energy credits and non-utility contracts as shown below: September 30, December 31, 2015 2014 (In millions) Emission allowances $ 1 $ 1 Renewable energy credits 49 45 Contract intangible assets 109 122 159 168 Less accumulated amortization 59 57 Intangible assets, net 100 111 Less current intangible assets 11 9 $ 89 $ 102 DTE Electric has certain intangible assets relating to emission allowances and renewable energy credits as shown below: September 30, December 31, 2015 2014 (In millions) Emission allowances $ 1 $ 1 Renewable energy credits 49 45 50 46 Less current intangible assets 11 9 $ 39 $ 37
Schedule of Effective Tax Rate and Unrecognized Tax Benefits	The effective tax rate and unrecognized tax benefits of the Registrants are as follows: Effective Tax Rate Unrecognized Tax Benefits Three Months Ended September 30, Nine Months Ended September 30, September 30, 2015 2014 2015 2014 2015 (In millions) DTE Energy 28 % 12 % 28 % 27 % $ 3 DTE Electric 35 % 36 % 35 % 36 % $ 4

Asset Retirement Obligations (T

Asset Retirement Obligations (Tables)	9 Months Ended
	Sep. 30, 2015
Asset Retirement Obligation Disclosure [Abstract]
Schedule of Change in Asset Retirement Obligation	A reconciliation of the ARO for the nine months ended September 30, 2015 follows: DTE Energy DTE Electric (In millions) Asset retirement obligations at December 31, 2014 $ 1,962 $ 1,796 Accretion 90 83 Revision in estimated cash flows 128 128 Asset retirement obligations at September 30, 2015 $ 2,180 $ 2,007

Earnings Per Share (Tables)

Earnings Per Share (Tables)	9 Months Ended
	Sep. 30, 2015
Earnings Per Share [Abstract]
Schedule of Earnings Per Share, Basic and Diluted	A reconciliation of both calculations is presented in the following table for the three and nine months ended September 30 : Three Months Ended September 30, Nine Months Ended September 30, 2015 2014 2015 2014 (In millions, except per share amounts) Basic Earnings per Share Net Income Attributable to DTE Energy Company $ 265 $ 156 $ 647 $ 606 Average number of common shares outstanding 179 177 179 177 Dividends declared — common shares $ 131 $ 122 $ 378 $ 353 Dividends declared — net restricted shares — — 1 1 Total distributed earnings $ 131 $ 122 $ 379 $ 354 Net Income less distributed earnings $ 134 $ 34 $ 268 $ 252 Distributed (dividends per common share) $ 0.73 $ 0.69 $ 2.11 $ 2.00 Undistributed 0.74 0.19 1.50 1.42 Total Basic Earnings per Common Share $ 1.47 $ 0.88 $ 3.61 $ 3.42 Diluted Earnings per Share Net Income Attributable to DTE Energy Company $ 265 $ 156 $ 647 $ 606 Average number of common shares outstanding 180 177 179 177 Dividends declared — common shares $ 131 $ 122 $ 378 $ 353 Dividends declared — net restricted shares — — 1 1 Total distributed earnings $ 131 $ 122 $ 379 $ 354 Net Income less distributed earnings $ 134 $ 34 $ 268 $ 252 Distributed (dividends per common share) $ 0.73 $ 0.69 $ 2.11 $ 2.00 Undistributed 0.74 0.19 1.50 1.42 Total Diluted Earnings per Common Share $ 1.47 $ 0.88 $ 3.61 $ 3.42

Fair Value (Tables)

Fair Value (Tables)	9 Months Ended
	Sep. 30, 2015
Fair Value Disclosures [Abstract]
Assets and liabilities measured and recorded at fair value on a recurring basis	The following table presents assets and liabilities for DTE Energy measured and recorded at fair value on a recurring basis as of September 30, 2015 and December 31, 2014 : September 30, 2015 December 31, 2014 Level 1 Level 2 Level 3 Netting Net Balance Level 1 Level 2 Level 3 Netting Net Balance (In millions) Assets: Cash equivalents (b) $ 11 $ 3 $ — $ — $ 14 $ 13 $ 99 $ — $ — $ 112 Nuclear decommissioning trusts 742 457 — — 1,199 792 449 — — 1,241 Other investments (c) 127 18 — — 145 100 50 — — 150 Derivative assets: Commodity Contracts: Natural Gas 162 87 54 (244 ) 59 555 140 92 (681 ) 106 Electricity — 204 47 (179 ) 72 — 295 47 (280 ) 62 Other 17 — 5 (17 ) 5 42 — 3 (42 ) 3 Other derivative contracts (d) — 10 — (8 ) 2 — 4 — (3 ) 1 Total derivative assets 179 301 106 (448 ) 138 597 439 142 (1,006 ) 172 Total $ 1,059 $ 779 $ 106 $ (448 ) $ 1,496 $ 1,502 $ 1,037 $ 142 $ (1,006 ) $ 1,675 Liabilities: Derivative liabilities: Commodity Contracts: Natural Gas $ (195 ) $ (49 ) $ (33 ) $ 249 $ (28 ) $ (578 ) $ (78 ) $ (62 ) $ 679 $ (39 ) Electricity — (200 ) (44 ) 190 (54 ) — (290 ) (52 ) 298 (44 ) Other (13 ) (4 ) (6 ) 22 (1 ) (32 ) (9 ) (4 ) 45 — Other derivative contracts (d) — (7 ) — 7 — — (5 ) — 3 (2 ) Total derivative liabilities (208 ) (260 ) (83 ) 468 (83 ) (610 ) (382 ) (118 ) 1,025 (85 ) Total $ (208 ) $ (260 ) $ (83 ) $ 468 $ (83 ) $ (610 ) $ (382 ) $ (118 ) $ 1,025 $ (85 ) Net Assets (Liabilities) at the end of the period $ 851 $ 519 $ 23 $ 20 $ 1,413 $ 892 $ 655 $ 24 $ 19 $ 1,590 Assets: Current $ 159 $ 225 $ 78 $ (358 ) $ 104 $ 582 $ 504 $ 109 $ (955 ) $ 240 Noncurrent (e) 900 554 28 (90 ) 1,392 920 533 33 (51 ) 1,435 Total Assets $ 1,059 $ 779 $ 106 $ (448 ) $ 1,496 $ 1,502 $ 1,037 $ 142 $ (1,006 ) $ 1,675 Liabilities: Current $ (160 ) $ (198 ) $ (61 ) $ 363 $ (56 ) $ (572 ) $ (357 ) $ (112 ) $ 964 $ (77 ) Noncurrent (48 ) (62 ) (22 ) 105 (27 ) (38 ) (25 ) (6 ) 61 (8 ) Total Liabilities $ (208 ) $ (260 ) $ (83 ) $ 468 $ (83 ) $ (610 ) $ (382 ) $ (118 ) $ 1,025 $ (85 ) Net Assets (Liabilities) at the end of the period $ 851 $ 519 $ 23 $ 20 $ 1,413 $ 892 $ 655 $ 24 $ 19 $ 1,590 _______________________________________ (a) Amounts represent the impact of master netting agreements that allow DTE Energy to net gain and loss positions and cash collateral held or placed with the same counterparties. (b) At September 30, 2015 , available-for-sale securities of $14 million included $6 million and $8 million of cash equivalents included in Restricted cash and Other investments on DTE Energy's Consolidated Statements of Financial Position, respectively. 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 DTE Energy's Consolidated Statements of Financial Position, respectively. (c) Excludes cash surrender value of life insurance investments. (d) Primarily includes foreign currency exchange contracts. (e) Includes $145 million and $150 million at September 30, 2015 and December 31, 2014 , respectively, of other investments that are included in DTE Energy's Consolidated Statements of Financial Position in Other investments. The following table presents assets for DTE Electric measured and recorded at fair value on a recurring basis as of September 30, 2015 and December 31, 2014 : September 30, 2015 December 31, 2014 Level 1 Level 2 Level 3 Net Balance Level 1 Level 2 Level 3 Net Balance (In millions) Assets: Cash equivalents (a) $ 5 $ 3 $ — $ 8 $ 5 $ 99 $ — $ 104 Nuclear decommissioning trusts 742 457 — 1,199 792 449 — 1,241 Other investments 7 — — 7 97 50 — 147 Derivative assets — FTRs — — 5 5 — — 3 3 Total $ 754 $ 460 $ 5 $ 1,219 $ 894 $ 598 $ 3 $ 1,495 Assets: Current $ 5 $ 3 $ 5 $ 13 $ 5 $ 99 $ 3 $ 107 Noncurrent 749 457 — 1,206 889 499 — 1,388 Total Assets $ 754 $ 460 $ 5 $ 1,219 $ 894 $ 598 $ 3 $ 1,495 _______________________________________ (a) At September 30, 2015 , available-for-sale securities of $8 million consisted of cash equivalents included in Other investments on DTE Electric's Consolidated Statements of Financial Position. At December 31, 2014 , available-for-sale securities of $104 million included $96 million and $8 million of cash equivalents included in Restricted cash and Other investments, respectively, on DTE Electric's Consolidated Statements of Financial Position.
Fair value reconciliation of level 3 assets and liabilities measured at fair value on a recurring basis	The following tables present the fair value reconciliation of Level 3 assets and liabilities measured at fair value on a recurring basis for DTE Energy for the three and nine months ended September 30, 2015 and 2014 : Three Months Ended September 30, 2015 Three Months Ended September 30, 2014 Natural Gas Electricity Other Total Natural Gas Electricity Other Total (In millions) Net Assets (Liabilities) as of June 30 $ (8 ) $ 3 $ 1 $ (4 ) $ (20 ) $ (27 ) $ 7 $ (40 ) Transfers into Level 3 from Level 2 — — — — 1 — — 1 Transfers from Level 3 into Level 2 — — — — (4 ) — — (4 ) Total gains (losses): Included in earnings 24 18 (3 ) 39 (2 ) 13 (1 ) 10 Recorded in regulatory assets/liabilities — — 3 3 — — (3 ) (3 ) Purchases, issuances, and settlements: Purchases — — — — — — — — Issuances — — — — — — — — Settlements 5 (18 ) (2 ) (15 ) (3 ) (3 ) — (6 ) Net Assets (Liabilities) as of September 30 $ 21 $ 3 $ (1 ) $ 23 $ (28 ) $ (17 ) $ 3 $ (42 ) 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 September 30, 2015 and 2014 and reflected in Operating revenues and Fuel, purchased power and gas in DTE Energy's Consolidated Statements of Operations $ 18 $ (3 ) $ (3 ) $ 12 $ (7 ) $ 14 $ (1 ) $ 6 Nine Months Ended September 30, 2015 Nine Months Ended September 30, 2014 Natural Gas Electricity Other Total Natural Gas Electricity Other Total (In millions) Net Assets (Liabilities) as of December 31 $ 30 $ (5 ) $ (1 ) $ 24 $ (52 ) $ 13 $ 3 $ (36 ) Transfers into Level 3 from Level 2 — — — — — — — — Transfers from Level 3 into Level 2 — — — — 2 — — 2 Total gains (losses): Included in earnings (11 ) 42 (5 ) 26 (45 ) 26 (2 ) (21 ) Recorded in regulatory assets/liabilities — — 14 14 — — 9 9 Purchases, issuances, and settlements: Purchases — 2 — 2 — 1 — 1 Issuances — — — — — (2 ) — (2 ) Settlements 2 (36 ) (9 ) (43 ) 67 (55 ) (7 ) 5 Net Assets (Liabilities) as of September 30 $ 21 $ 3 $ (1 ) $ 23 $ (28 ) $ (17 ) $ 3 $ (42 ) 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 September 30, 2015 and 2014 and reflected in Operating revenues and Fuel, purchased power and gas in DTE Energy's Consolidated Statements of Operations $ (94 ) $ 8 $ (4 ) $ (90 ) $ (23 ) $ (6 ) $ (1 ) $ (30 ) The following table presents the fair value reconciliation of Level 3 assets and liabilities measured at fair value on a recurring basis for DTE Electric for the three and nine months ended September 30, 2015 and 2014 : Three Months Ended September 30, Nine Months Ended September 30, 2015 2014 2015 2014 (In millions) Net Assets as of beginning of period $ 5 $ 7 $ 3 $ 3 Change in fair value recorded in regulatory assets/liabilities 3 (3 ) 14 9 Purchases, issuances, and settlements: Settlements (3 ) — (12 ) (8 ) Net Assets as of September 30 $ 5 $ 4 $ 5 $ 4 The amount of total gains (losses) included in Regulatory assets and liabilities attributed to the change in unrealized gains (losses) related to assets and liabilities held at September 30, 2015 and 2014 and reflected in DTE Electric's Consolidated Statements of Financial Position $ 1 $ (1 ) $ 5 $ 4
Unobservable inputs related to Level 3 assets and liabilities	The following table presents the unobservable inputs related to DTE Energy's Level 3 assets and liabilities as of September 30, 2015 : September 30, 2015 Commodity Contracts Derivative Assets Derivative Liabilities Valuation Techniques Unobservable Input Range Weighted Average (In millions) Natural Gas $ 54 $ (33 ) Discounted Cash Flow Forward basis price (per MMBtu) $ (1.73 ) — $ 6.57 /MMBtu $ (0.11 )/MMBtu Electricity $ 47 $ (44 ) Discounted Cash Flow Forward basis price (per MWh) $ (8 ) — $ 15 /MWh $ 1 /MWh The following table presents the unobservable inputs related to DTE Energy's Level 3 assets and liabilities as of December 31, 2014 : 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
Carrying amount of fair value of financial instruments	The following table presents the carrying amount and fair value of financial instruments for DTE Energy as of September 30, 2015 and December 31, 2014 : September 30, 2015 December 31, 2014 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 $ 34 $ — $ — $ 34 $ 41 $ — $ — $ 41 Dividends payable $ 131 $ 131 $ — $ — $ 122 $ 122 $ — $ — Short-term borrowings $ 185 $ — $ 185 $ — $ 398 $ — $ 398 $ — Long-term debt, excluding capital leases $ 9,310 $ 480 $ 8,289 $ 1,186 $ 8,606 $ 489 $ 8,308 $ 706 The following table presents the carrying amount and fair value of financial instruments for DTE Electric as of September 30, 2015 and December 31, 2014 : September 30, 2015 December 31, 2014 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 $ 6 $ — $ — $ 6 $ 12 $ — $ — $ 12 Notes receivable — affiliates $ 4 $ — $ — $ 4 $ 8 $ — $ — $ 8 Short-term borrowings — affiliates $ 68 $ — $ — $ 68 $ 84 $ — $ — $ 84 Short-term borrowings — other $ 46 $ — $ 46 $ — 50 $ — $ 50 $ — Long-term debt, excluding capital leases $ 5,644 $ — $ 5,496 $ 562 $ 5,259 $ — $ 5,341 $ 496
Fair value of nuclear decommissioning trust fund assets	The following table summarizes DTE Electric's fair value of the nuclear decommissioning trust fund assets: September 30, 2015 December 31, 2014 (In millions) Fermi 2 $ 1,175 $ 1,221 Fermi 1 3 3 Low-level radioactive waste 21 17 Total $ 1,199 $ 1,241
Schedule of realized gain (loss)	The following table sets forth DTE Electric's gains and losses and proceeds from the sale of securities by the nuclear decommissioning trust funds: Three Months Ended September 30, Nine Months Ended September 30, 2015 2014 2015 2014 (In millions) Realized gains $ 8 $ 8 $ 30 $ 24 Realized losses $ (10 ) $ (3 ) $ (23 ) $ (14 ) Proceeds from sales of securities $ 187 $ 177 $ 627 $ 652
Fair value and unrealized gains for nuclear decommissioning trust fund	The following table sets forth DTE Electric's fair value and unrealized gains and losses for the nuclear decommissioning trust funds: September 30, 2015 December 31, 2014 Fair Unrealized Unrealized Fair Unrealized Unrealized (In millions) Equity securities $ 708 $ 169 $ (74 ) $ 756 $ 204 $ (39 ) Debt securities 484 18 (2 ) 474 21 (2 ) Cash and cash equivalents 7 — — 11 — — $ 1,199 $ 187 $ (76 ) $ 1,241 $ 225 $ (41 )

Financial and Other Derivativ30

Financial and Other Derivative Instruments (Tables)	9 Months Ended
	Sep. 30, 2015
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Fair value of derivative instruments	The following table presents the fair value of derivative instruments as of September 30, 2015 and December 31, 2014 for DTE Energy: September 30, 2015 December 31, 2014 Derivative Assets Derivative Liabilities Derivative Assets Derivative Liabilities (In millions) Derivatives not designated as hedging instruments: Foreign currency exchange contracts $ 10 $ (7 ) $ 4 $ (5 ) Commodity Contracts: Natural Gas 303 (277 ) 787 (718 ) Electricity 251 (244 ) 342 (342 ) Other 22 (23 ) 45 (45 ) Total derivatives not designated as hedging instruments: $ 586 $ (551 ) $ 1,178 $ (1,110 ) Total derivatives: Current $ 448 $ (419 ) $ 1,083 $ (1,041 ) Noncurrent 138 (132 ) 95 (69 ) Total derivatives $ 586 $ (551 ) $ 1,178 $ (1,110 ) The following table presents the fair value of derivative instruments as of September 30, 2015 and December 31, 2014 for DTE Electric: September 30, 2015 December 31, 2014 (In millions) FTRs — Other current assets $ 5 $ 3 Total derivatives not designated as hedging instrument $ 5 $ 3
Netting Offsets of Derivative Assets and Liabilities	The following table presents the netting offsets of derivative assets and liabilities for DTE Energy at September 30, 2015 and December 31, 2014 : September 30, 2015 December 31, 2014 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 $ 303 $ (244 ) $ 59 $ 787 $ (681 ) $ 106 Electricity 251 (179 ) 72 342 (280 ) 62 Other 22 (17 ) 5 45 (42 ) 3 Other derivative contracts (a) 10 (8 ) 2 4 (3 ) 1 Total derivative assets $ 586 $ (448 ) $ 138 $ 1,178 $ (1,006 ) $ 172 Derivative liabilities: Commodity Contracts: Natural Gas $ (277 ) $ 249 $ (28 ) $ (718 ) $ 679 $ (39 ) Electricity (244 ) 190 (54 ) (342 ) 298 (44 ) Other (23 ) 22 (1 ) (45 ) 45 — Other derivative contracts (a) (7 ) 7 — (5 ) 3 (2 ) Total derivative liabilities $ (551 ) $ 468 $ (83 ) $ (1,110 ) $ 1,025 $ (85 ) _______________________________________ (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 showing the reconciliation of derivative instruments to DTE Energy's Consolidated Statements of Financial Position at September 30, 2015 and December 31, 2014 : September 30, 2015 December 31, 2014 Derivative Assets Derivative Liabilities Derivative Assets Derivative Liabilities Current Noncurrent Current Noncurrent Current Noncurrent Current Noncurrent (In millions) Total fair value of derivatives $ 448 $ 138 $ (419 ) $ (132 ) $ 1,083 $ 95 $ (1,041 ) $ (69 ) Counterparty netting (358 ) (89 ) 358 89 (955 ) (51 ) 955 51 Collateral adjustment — (1 ) 5 16 — — 9 10 Total derivatives as reported $ 90 $ 48 $ (56 ) $ (27 ) $ 128 $ 44 $ (77 ) $ (8 )
Gain (Loss) Recognized in Income on Derivative	The effect of derivatives not designated as hedging instruments on DTE Energy's Consolidated Statements of Operations for the three and nine months ended September 30, 2015 and 2014 for DTE Energy is as follows: Derivatives not Designated as Hedging Instruments Location of Gain Gain (Loss) Recognized in Income on Derivatives for the Three Months Ended September 30, Gain (Loss) Recognized in Income on Derivatives for the Nine Months Ended September 30, 2015 2014 2015 2014 (In millions) Foreign currency exchange contracts Operating Revenue $ 1 $ (1 ) $ 2 $ (2 ) Commodity Contracts: Natural Gas Operating Revenue 55 (38 ) (75 ) (10 ) Natural Gas Fuel, purchased power, and gas (24 ) 12 9 23 Electricity Operating Revenue 14 12 60 100 Other Operating Revenue (4 ) (1 ) (4 ) (5 ) Total $ 42 $ (16 ) $ (8 ) $ 106
Volume of Commodity Contracts	The following represents the cumulative gross volume of DTE Energy's derivative contracts outstanding as of September 30, 2015 : Commodity Number of Units Natural Gas (MMBtu) 1,083,436,935 Electricity (MWh) 22,421,752 Oil (Gallons) 23,520,000 Foreign Currency Exchange (Canadian dollars) 42,420,220

Long-Term Debt (Tables)

Long-Term Debt (Tables)	9 Months Ended
	Sep. 30, 2015
Long-term Debt, Unclassified [Abstract]
Schedule of Debt	In 2015 , the following debt was issued: Company Month Type Interest Rate Maturity Amount (In millions) DTE Electric March Mortgage Bonds (a) 3.70% 2045 $ 500 DTE Energy June Senior Notes (b) 3.30% 2022 300 DTE Gas August Mortgage Bonds (c) 3.35% 2027 40 DTE Gas August Mortgage Bonds (c) 4.21% 2045 125 $ 965 _______________________________________ (a) Proceeds were used for the redemption of long-term debt, for the repayment of short-term borrowings, and for general corporate purposes. (b) Proceeds were used for general corporate purposes. (c) Proceeds were used for the redemption of long-term debt and for general corporate purposes.
Schedule of Debt Redemptions	In 2015 , the following debt was redeemed: Company Month Type Interest Rate Maturity Amount (In millions) DTE Electric March Securitization Bonds 6.62% 2015 $ 105 DTE Electric March Mortgage Bonds 7.904% 2016 10 DTE Gas September Senior Notes 5.94% 2015 140 DTE Energy Various Other Long Term Debt Various 2015 5 $ 260

Short-Term Credit Arrangement32

Short-Term Credit Arrangements and Borrowings (Tables)	9 Months Ended
	Sep. 30, 2015
Short-term Debt [Abstract]
Schedule of Line of Credit Facilities	The availability under the facilities in place at September 30, 2015 is shown in the following table: DTE Energy DTE Electric DTE Gas Total (In millions) Unsecured letter of credit facility, expiring in February 2017 $ 100 $ — $ — $ 100 Unsecured letter of credit facility, expiring in September 2017 70 — — 70 Unsecured revolving credit facility, expiring April 2020 1,200 400 300 1,900 1,370 400 300 2,070 Amounts outstanding at September 30, 2015: Commercial paper issuances 11 46 128 185 Letters of credit 185 — — 185 196 46 128 370 Net availability at September 30, 2015 $ 1,174 $ 354 $ 172 $ 1,700

Retirement Benefits and Trust33

Retirement Benefits and Trusteed Assets (Tables)	9 Months Ended
	Sep. 30, 2015
Defined Benefit Pension Plans and Defined Benefit Postretirement Plans Disclosure [Abstract]
Schedule of Net Benefit Costs	The following table details the components of net periodic benefit costs for pension benefits and other postretirement benefits for DTE Energy: Pension Benefits Other Postretirement Benefits 2015 2014 2015 2014 Three Months Ended September 30, (In millions) Service cost $ 27 $ 19 $ 8 $ 8 Interest cost 52 54 20 22 Expected return on plan assets (74 ) (69 ) (33 ) (31 ) Amortization of: Net actuarial loss 51 42 10 4 Prior service credit — — (31 ) (36 ) Net periodic benefit cost (credit) $ 56 $ 46 $ (26 ) $ (33 ) Pension Benefits Other Postretirement Benefits 2015 2014 2015 2014 Nine Months Ended September 30, (In millions) Service cost $ 76 $ 62 $ 25 $ 26 Interest cost 158 159 61 67 Expected return on plan assets (222 ) (205 ) (98 ) (92 ) Amortization of: Net actuarial loss 154 118 32 15 Prior service credit — — (94 ) (108 ) Net periodic benefit cost (credit) $ 166 $ 134 $ (74 ) $ (92 ) The following table details the components of net periodic benefit costs for pension benefits and other postretirement benefits for DTE Electric: Pension Benefits Other Postretirement Benefits 2015 2014 2015 2014 Three Months Ended September 30, (In millions) Service cost $ 21 $ 14 $ 6 $ 6 Interest cost 39 41 15 17 Expected return on plan assets (53 ) (48 ) (23 ) (21 ) Amortization of: Net actuarial loss 36 30 8 3 Prior service credit — — (24 ) (27 ) Net periodic benefit cost (credit) $ 43 $ 37 $ (18 ) $ (22 ) Pension Benefits Other Postretirement Benefits 2015 2014 2015 2014 Nine Months Ended September 30, (In millions) Service cost $ 59 $ 48 $ 19 $ 19 Interest cost 120 121 46 51 Expected return on plan assets (158 ) (145 ) (68 ) (63 ) Amortization of: Net actuarial loss 110 83 24 11 Prior service cost (credit) 1 1 (71 ) (82 ) Net periodic benefit cost (credit) $ 132 $ 108 $ (50 ) $ (64 )
Schedule of Contributions	During 2015 , DTE Energy contributed the following amounts of DTE Energy common stock to the DTE Energy Company Master VEBA Trust for funding its other postretirement benefit plans: Date Number of Shares Price per Share Amount (In millions) February 17, 2015 1,427,835 $81.91 $ 117 $ 117

Stock-Based Compensation (Table

Stock-Based Compensation (Tables)	9 Months Ended
	Sep. 30, 2015
Share-based Compensation [Abstract]
Schedule of Stock-based Compensation	The following table summarizes the components of stock-based compensation for DTE Energy: Three Months Ended September 30, Nine Months Ended September 30, 2015 2014 2015 2014 (In millions) Stock-based compensation expense $ 12 $ 22 $ 32 $ 72 Tax benefit $ 5 $ 8 $ 13 $ 27 Stock-based compensation cost capitalized in Property, plant, and equipment $ 2 $ 4 $ 5 $ 11
Schedule of Stock Option Activity	The following table summarizes DTE Energy's stock option activity for the nine months ended September 30, 2015 : Number of Weighted Aggregate Intrinsic Value Options outstanding at December 31, 2014 444,278 $ 43.56 Exercised (178,017 ) $ 45.07 Forfeited or expired (3,979 ) $ 44.72 Options outstanding and exercisable at September 30, 2015 262,282 $ 42.52 $ 9
Schedule of Restricted Stock Activity	The following table summarizes DTE Energy’s restricted stock awards activity for the nine months ended September 30, 2015 : Restricted Weighted Average Grant Date Fair Value Balance at December 31, 2014 416,318 $ 62.82 Grants 143,800 $ 83.44 Forfeitures (8,975 ) $ 73.62 Vested and issued (158,920 ) $ 55.36 Balance at September 30, 2015 392,223 $ 73.15
Schedule of Performance Share Activity	The following table summarizes DTE Energy’s performance share activity for the nine months ended September 30, 2015 : Performance Weighted Average Grant Date Fair Value Balance at December 31, 2014 1,554,697 $ 69.32 Grants 454,654 $ 83.86 Forfeitures (37,112 ) $ 75.90 Payouts (532,700 ) $ — Balance at September 30, 2015 1,439,539 $ 75.80

Segment and Related Informati35

Segment and Related Information (Tables)	9 Months Ended
	Sep. 30, 2015
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: Three Months Ended September 30, Nine Months Ended September 30, 2015 2014 2015 2014 (In millions) Inter-segment Revenues Electric $ 9 $ 8 $ 27 $ 22 Gas 1 1 2 5 Gas Storage and Pipelines 1 1 7 9 Power and Industrial Projects 204 211 599 593 Energy Trading 7 8 23 24 Corporate and Other 1 1 2 2 $ 223 $ 230 $ 660 $ 655 Financial data of the DTE Energy business segments follows: Three Months Ended September 30, Nine Months Ended September 30, 2015 2014 2015 2014 (In millions) Operating Revenues Electric $ 1,386 $ 1,358 $ 3,737 $ 4,049 Gas 153 149 1,018 1,182 Gas Storage and Pipelines 61 49 175 146 Power and Industrial Projects 585 605 1,708 1,703 Energy Trading 635 664 1,870 2,797 Corporate and Other 1 — 2 1 Reconciliation and Eliminations (223 ) (230 ) (660 ) (655 ) Total $ 2,598 $ 2,595 $ 7,850 $ 9,223 Net Income (Loss) Attributable to DTE Energy by Segment: Electric $ 214 $ 135 $ 449 $ 400 Gas (11 ) (16 ) 93 109 Gas Storage and Pipelines 27 20 79 59 Power and Industrial Projects 32 38 73 66 Energy Trading 12 (22 ) — 6 Corporate and Other (9 ) 1 (47 ) (34 ) Net Income Attributable to DTE Energy Company $ 265 $ 156 $ 647 $ 606

Organization and Basis of Pre36

Organization and Basis of Presentation (Details Textuals) customer in Millions	Sep. 30, 2015USD ($)customer
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Number of electric utility customers	2.1
Number of gas utility customers	1.2
Significant Potential Exposure to Loss Due to VIE Long-Term Purchase Contracts | $	$ 0
DTE Electric
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Significant Potential Exposure to Loss Due to VIE Long-Term Purchase Contracts | $	$ 0

Organization and Basis of Pre37

Organization and Basis of Presentation (Consolidated Variable Interest Entities) (Details) - USD ($) $ in Millions	Sep. 30, 2015	Dec. 31, 2014	Sep. 30, 2014	Dec. 31, 2013
Variable Interest Entity [Line Items]
Securitized regulatory assets	$ 0	$ 34
ASSETS
Cash and cash equivalents	67	48	$ 60	$ 52
Restricted cash	21	120
Accounts receivable	1,242	1,504
Property, plant, and equipment, net	17,867	16,820
Total Assets	28,654	27,974
LIABILITIES
Current portion long-term debt, including capital leases	468	274
Current regulatory liabilities	67	153
Mortgage bonds, notes, and other	8,368	7,860
Capital lease obligations	8	3
Variable Interest Entity, Primary Beneficiary
Variable Interest Entity [Line Items]
Securitized regulatory assets	0	34
ASSETS
Cash and cash equivalents	12	7
Restricted cash	6	104
Accounts receivable	14	41
Inventories	43	67
Property, plant, and equipment, net	70	81
Other current and long-term assets	4	7
Total Assets	149	341
LIABILITIES
Accounts payable and accrued current liabilities	11	11
Current portion long-term debt, including capital leases	9	115
Current regulatory liabilities	0	32
Mortgage bonds, notes, and other	11	15
Capital lease obligations	0	3
Other current and long-term liabilities	6	15
Total Liabilities	$ 37	191
Variable Interest Entity, Primary Beneficiary Securitization
Variable Interest Entity [Line Items]
Securitized regulatory assets		34
ASSETS
Cash and cash equivalents		0
Restricted cash		96
Accounts receivable		26
Inventories		0
Property, plant, and equipment, net		0
Other current and long-term assets		1
Total Assets		157
LIABILITIES
Accounts payable and accrued current liabilities		3
Current portion long-term debt, including capital leases		105
Current regulatory liabilities		32
Mortgage bonds, notes, and other		0
Capital lease obligations		0
Other current and long-term liabilities		9
Total Liabilities		149
Variable Interest Entity, Primary Beneficiary Other
Variable Interest Entity [Line Items]
Securitized regulatory assets		0
ASSETS
Cash and cash equivalents		7
Restricted cash		8
Accounts receivable		15
Inventories		67
Property, plant, and equipment, net		81
Other current and long-term assets		6
Total Assets		184
LIABILITIES
Accounts payable and accrued current liabilities		8
Current portion long-term debt, including capital leases		10
Current regulatory liabilities		0
Mortgage bonds, notes, and other		15
Capital lease obligations		3
Other current and long-term liabilities		6
Total Liabilities		$ 42

Organization and Basis of Pre38

Organization and Basis of Presentation (Non Consolidated Variable Interest Entities) (Details) - USD ($) $ in Millions	Sep. 30, 2015	Dec. 31, 2014
Variable Interest Entity [Line Items]
Notes receivable	$ 82	$ 90
Variable Interest Entity, Not Primary Beneficiary
Variable Interest Entity [Line Items]
Other investments	138	134
Notes receivable	$ 15	$ 15

Significant Accounting Polici39

Significant Accounting Policies (Details Textuals) - USD ($) $ in Millions	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014	Dec. 31, 2014
Significant Accounting Policies [Line Items]
Other income	$ 55	$ 55	$ 155	$ 136
Deferred tax expense					$ 8
Unrecognized tax benefits that would impact effective tax rate	2		2
Decrease in unrecognized tax benefits	6
Power and Industrial Projects
Significant Accounting Policies [Line Items]
Other income	24	25	$ 64	57
Minimum
Significant Accounting Policies [Line Items]
Finite-lived intangible asset, useful life			1 year
Maximum
Significant Accounting Policies [Line Items]
Finite-lived intangible asset, useful life			26 years
DTE Electric
Significant Accounting Policies [Line Items]
Other income	14	$ 15	$ 42	$ 45
DTE Electric | DTE Energy
Significant Accounting Policies [Line Items]
Income tax receivable	$ 68		$ 68		$ 29

Significant Accounting Polici40

Significant Accounting Policies (Intangible Assets) (Details) - USD ($) $ in Millions	Sep. 30, 2015	Dec. 31, 2014
Finite-Lived Intangible Assets [Line Items]
Intangible assets, gross	$ 159	$ 168
Less accumulated amortization	59	57
Intangible assets, net	100	111
Less current intangible assets	11	9
Intangible assets	89	102
Emission allowances
Finite-Lived Intangible Assets [Line Items]
Indefinite-lived intangible assets, gross	1	1
DTE Electric
Finite-Lived Intangible Assets [Line Items]
Intangible assets, gross	50	46
Less current intangible assets	11	9
Intangible assets	39	37
DTE Electric | Emission allowances
Finite-Lived Intangible Assets [Line Items]
Indefinite-lived intangible assets, gross	1	1
Renewable energy credits
Finite-Lived Intangible Assets [Line Items]
Finite-lived intangible assets, gross	49	45
Renewable energy credits | DTE Electric
Finite-Lived Intangible Assets [Line Items]
Finite-lived intangible assets, gross	49	45
Contract intangible assets
Finite-Lived Intangible Assets [Line Items]
Finite-lived intangible assets, gross	$ 109	$ 122

Significant Accounting Polici41

Significant Accounting Policies (Income Taxes) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Schedule of Income Taxes [Line Items]
Effective Tax Rate	28.00%	12.00%	28.00%	27.00%
Unrecognized Tax Benefits	$ 3		$ 3
DTE Electric
Schedule of Income Taxes [Line Items]
Effective Tax Rate	35.00%	36.00%	35.00%	36.00%
Unrecognized Tax Benefits	$ 4		$ 4

Acquisitions (Details)

Acquisitions (Details) - DTE Electric $ in Millions	Oct. 01, 2015USD ($)MW	Jan. 21, 2015USD ($)MW
Natural Gas Facility in Carson City Michigan
Business Acquisition [Line Items]
Gas facility capacity, MW		732
Total purchase price | $		$ 241
Subsequent event | Natural Gas Facility in East China Township Michigan
Business Acquisition [Line Items]
Gas facility capacity, MW	350
Total purchase price | $	$ 69

Asset Retirement Obligations (D

Asset Retirement Obligations (Details) $ in Millions	9 Months Ended
	Sep. 30, 2015USD ($)
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]
Asset retirement obligations at December 31, 2014	$ 1,962
Accretion	90
Revision in estimated cash flows	128
Asset retirement obligations at September 30, 2015	2,180
DTE Electric
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]
Asset retirement obligations at December 31, 2014	1,796
Accretion	83
Revision in estimated cash flows	128
Asset retirement obligations at September 30, 2015	$ 2,007

Regulatory Matters (Details Tex

Regulatory Matters (Details Textuals) - DTE Electric - USD ($) $ in Millions	Jul. 01, 2015	Dec. 19, 2014	Jul. 31, 2015	Jul. 31, 2014
MPSC
Public Utilities, General Disclosures [Line Items]
Requested rate increase		$ 370
Rate increase amount	$ 230
Refund sought				$ 22
Refund awarded			$ 20
Interest rate on refund obligation			7.00%
Customer refund			$ 25
PSCR
Public Utilities, General Disclosures [Line Items]
Refund obligation expected to be recovered			$ 16
December 19, 2014 Rate Request | MPSC
Public Utilities, General Disclosures [Line Items]
Rate increase amount	190
Required elimination of a credit surcharge | MPSC
Public Utilities, General Disclosures [Line Items]
Rate increase amount	$ 40

Earnings Per Share (Details)

Earnings Per Share (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Basic Earnings per Share
Net Income Attributable to DTE Energy Company/DTE Electric	$ 265	$ 156	$ 647	$ 606
Average number of common shares outstanding (in shares)	179	177	179	177
Dividends declared — common shares	$ 131	$ 122	$ 378	$ 353
Dividends declared — net restricted shares	0	0	1	1
Total distributed earnings	131	122	379	354
Net Income less distributed earnings	$ 134	$ 34	$ 268	$ 252
Distributed (dividends per common share) (dollars per share)	$ 0.73	$ 0.69	$ 2.11	$ 2
Undistributed (in dollars per share)	0.74	0.19	1.50	1.42
Total Basic Earnings per Common Share (dollars per share)	$ 1.47	$ 0.88	$ 3.61	$ 3.42
Diluted Earnings per Share
Net Income Attributable to DTE Energy Company/DTE Electric	$ 265	$ 156	$ 647	$ 606
Average number of common shares outstanding (in shares)	180	177	179	177
Dividends declared — common shares	$ 131	$ 122	$ 378	$ 353
Dividends declared — net restricted shares	0	0	1	1
Total distributed earnings	131	122	379	354
Net Income less distributed earnings	$ 134	$ 34	$ 268	$ 252
Distributed (dividends per common share) (dollars per share)	$ 0.73	$ 0.69	$ 2.11	$ 2
Undistributed (dollars per share)	0.74	0.19	1.50	1.42
Total Diluted Earnings per Common Share (dollars per share)	$ 1.47	$ 0.88	$ 3.61	$ 3.42

Fair Value (Assets and Liabilit

Fair Value (Assets and Liabilities Recorded at Fair Value on a Recurring Basis) (Details) - USD ($) $ in Millions	Sep. 30, 2015	Dec. 31, 2014
Derivative Assets
Derivative asset, gross	$ 586	$ 1,178
Derivative asset, netting	(448)	(1,006)
Derivative assets, net	138	172
Derivative Liabilities
Derivative liability, gross	(551)	(1,110)
Derivative liability, netting	468	1,025
Derivative liabilities, net	(83)	(85)
Current derivative liability
Derivative Liabilities
Derivative liability, gross	(419)	(1,041)
Noncurrent derivative liability
Derivative Liabilities
Derivative liability, gross	(132)	(69)
Natural Gas
Derivative Assets
Derivative asset, gross	303	787
Derivative asset, netting	(244)	(681)
Derivative assets, net	59	106
Derivative Liabilities
Derivative liability, gross	(277)	(718)
Derivative liability, netting	249	679
Derivative liabilities, net	(28)	(39)
Electricity
Derivative Assets
Derivative asset, gross	251	342
Derivative asset, netting	(179)	(280)
Derivative assets, net	72	62
Derivative Liabilities
Derivative liability, gross	(244)	(342)
Derivative liability, netting	190	298
Derivative liabilities, net	(54)	(44)
Other
Derivative Assets
Derivative asset, gross	22	45
Derivative asset, netting	(17)	(42)
Derivative assets, net	5	3
Derivative Liabilities
Derivative liability, gross	(23)	(45)
Derivative liability, netting	22	45
Derivative liabilities, net	(1)	0
Other derivative contract
Derivative Assets
Derivative asset, gross	10	4
Derivative asset, netting	(8)	(3)
Derivative assets, net	2	1
Derivative Liabilities
Derivative liability, gross	(7)	(5)
Derivative liability, netting	7	3
Derivative liabilities, net	0	(2)
Recurring
ASSETS
Cash and cash equivalents	14	112
Nuclear decommissioning trusts	1,199	1,241
Other investments	145	150
Derivative Assets
Derivative asset, netting	(448)	(1,006)
Derivative assets, net	138	172
Total assets	1,496	1,675
Derivative Liabilities
Derivative liability, netting	468	1,025
Derivative liabilities, net	(83)	(85)
Net asset (liability)	1,413	1,590
Net assets (liabilities), netting	20	19
Recurring | Current asset
Derivative Assets
Derivative asset, netting	(358)	(955)
Total assets	104	240
Recurring | Noncurrent asset
Derivative Assets
Derivative asset, netting	(90)	(51)
Total assets	1,392	1,435
Recurring | Current derivative liability
Derivative Liabilities
Derivative liability, netting	363	964
Derivative liabilities, net	(56)	(77)
Recurring | Noncurrent derivative liability
Derivative Liabilities
Derivative liability, netting	105	61
Derivative liabilities, net	(27)	(8)
Recurring | Natural Gas
Derivative Assets
Derivative asset, netting	(244)	(681)
Derivative assets, net	59	106
Derivative Liabilities
Derivative liability, netting	249	679
Derivative liabilities, net	(28)	(39)
Recurring | Electricity
Derivative Assets
Derivative asset, netting	(179)	(280)
Derivative assets, net	72	62
Derivative Liabilities
Derivative liability, netting	190	298
Derivative liabilities, net	(54)	(44)
Recurring | Other
Derivative Assets
Derivative asset, netting	(17)	(42)
Derivative assets, net	5	3
Derivative Liabilities
Derivative liability, netting	22	45
Derivative liabilities, net	(1)	0
Recurring | Other derivative contract
Derivative Assets
Derivative asset, netting	(8)	(3)
Derivative assets, net	2	1
Derivative Liabilities
Derivative liability, netting	7	3
Derivative liabilities, net	0	(2)
Recurring | Level 1
ASSETS
Cash and cash equivalents	11	13
Nuclear decommissioning trusts	742	792
Other investments	127	100
Derivative Assets
Derivative asset, gross	179	597
Total assets	1,059	1,502
Derivative Liabilities
Derivative liability, gross	(208)	(610)
Net asset (liability)	851	892
Recurring | Level 1 | Current asset
Derivative Assets
Total assets	159	582
Recurring | Level 1 | Noncurrent asset
Derivative Assets
Total assets	900	920
Recurring | Level 1 | Current derivative liability
Derivative Liabilities
Derivative liability, gross	(160)	(572)
Recurring | Level 1 | Noncurrent derivative liability
Derivative Liabilities
Derivative liability, gross	(48)	(38)
Recurring | Level 1 | Natural Gas
Derivative Assets
Derivative asset, gross	162	555
Derivative Liabilities
Derivative liability, gross	(195)	(578)
Recurring | Level 1 | Electricity
Derivative Assets
Derivative asset, gross	0	0
Derivative Liabilities
Derivative liability, gross	0	0
Recurring | Level 1 | Other
Derivative Assets
Derivative asset, gross	17	42
Derivative Liabilities
Derivative liability, gross	(13)	(32)
Recurring | Level 1 | Other derivative contract
Derivative Assets
Derivative asset, gross	0	0
Derivative Liabilities
Derivative liability, gross	0	0
Recurring | Level 2
ASSETS
Cash and cash equivalents	3	99
Nuclear decommissioning trusts	457	449
Other investments	18	50
Derivative Assets
Derivative asset, gross	301	439
Total assets	779	1,037
Derivative Liabilities
Derivative liability, gross	(260)	(382)
Net asset (liability)	519	655
Recurring | Level 2 | Current asset
Derivative Assets
Total assets	225	504
Recurring | Level 2 | Noncurrent asset
Derivative Assets
Total assets	554	533
Recurring | Level 2 | Current derivative liability
Derivative Liabilities
Derivative liability, gross	(198)	(357)
Recurring | Level 2 | Noncurrent derivative liability
Derivative Liabilities
Derivative liability, gross	(62)	(25)
Recurring | Level 2 | Natural Gas
Derivative Assets
Derivative asset, gross	87	140
Derivative Liabilities
Derivative liability, gross	(49)	(78)
Recurring | Level 2 | Electricity
Derivative Assets
Derivative asset, gross	204	295
Derivative Liabilities
Derivative liability, gross	(200)	(290)
Recurring | Level 2 | Other
Derivative Assets
Derivative asset, gross	0	0
Derivative Liabilities
Derivative liability, gross	(4)	(9)
Recurring | Level 2 | Other derivative contract
Derivative Assets
Derivative asset, gross	10	4
Derivative Liabilities
Derivative liability, gross	(7)	(5)
Recurring | Level 3
ASSETS
Cash and cash equivalents	0	0
Nuclear decommissioning trusts	0	0
Other investments	0	0
Derivative Assets
Derivative asset, gross	106	142
Total assets	106	142
Derivative Liabilities
Derivative liability, gross	(83)	(118)
Net asset (liability)	23	24
Recurring | Level 3 | Current asset
Derivative Assets
Total assets	78	109
Recurring | Level 3 | Noncurrent asset
Derivative Assets
Total assets	28	33
Recurring | Level 3 | Current derivative liability
Derivative Liabilities
Derivative liability, gross	(61)	(112)
Recurring | Level 3 | Noncurrent derivative liability
Derivative Liabilities
Derivative liability, gross	(22)	(6)
Recurring | Level 3 | Natural Gas
Derivative Assets
Derivative asset, gross	54	92
Derivative Liabilities
Derivative liability, gross	(33)	(62)
Recurring | Level 3 | Electricity
Derivative Assets
Derivative asset, gross	47	47
Derivative Liabilities
Derivative liability, gross	(44)	(52)
Recurring | Level 3 | Other
Derivative Assets
Derivative asset, gross	5	3
Derivative Liabilities
Derivative liability, gross	(6)	(4)
Recurring | Level 3 | Other derivative contract
Derivative Assets
Derivative asset, gross	0	0
Derivative Liabilities
Derivative liability, gross	0	0
DTE Electric | Recurring
ASSETS
Cash and cash equivalents	8	104
Nuclear decommissioning trusts	1,199	1,241
Other investments	7	147
Derivative Assets
Total assets	1,219	1,495
DTE Electric | Recurring | Current asset
Derivative Assets
Total assets	13	107
DTE Electric | Recurring | Noncurrent asset
Derivative Assets
Total assets	1,206	1,388
DTE Electric | Recurring | Financial transmission rights
Derivative Assets
Derivative assets, net	5	3
DTE Electric | Recurring | Level 1
ASSETS
Cash and cash equivalents	5	5
Nuclear decommissioning trusts	742	792
Other investments	7	97
Derivative Assets
Total assets	754	894
DTE Electric | Recurring | Level 1 | Current asset
Derivative Assets
Total assets	5	5
DTE Electric | Recurring | Level 1 | Noncurrent asset
Derivative Assets
Total assets	749	889
DTE Electric | Recurring | Level 1 | Financial transmission rights
Derivative Assets
Derivative assets, net	0	0
DTE Electric | Recurring | Level 2
ASSETS
Cash and cash equivalents	3	99
Nuclear decommissioning trusts	457	449
Other investments	0	50
Derivative Assets
Total assets	460	598
DTE Electric | Recurring | Level 2 | Current asset
Derivative Assets
Total assets	3	99
DTE Electric | Recurring | Level 2 | Noncurrent asset
Derivative Assets
Total assets	457	499
DTE Electric | Recurring | Level 2 | Financial transmission rights
Derivative Assets
Derivative assets, net	0	0
DTE Electric | Recurring | Level 3
ASSETS
Cash and cash equivalents	0	0
Nuclear decommissioning trusts	0	0
Other investments	0	0
Derivative Assets
Total assets	5	3
DTE Electric | Recurring | Level 3 | Current asset
Derivative Assets
Total assets	5	3
DTE Electric | Recurring | Level 3 | Noncurrent asset
Derivative Assets
Total assets	0	0
DTE Electric | Recurring | Level 3 | Financial transmission rights
Derivative Assets
Derivative assets, net	$ 5	$ 3

Fair Value (Reconciliation of L

Fair Value (Reconciliation of Level 3 Assets and Liabilities at Fair Value on a Recurring Basis) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Fair value reconciliation of Level 3 assets and liabilities measured at fair value on a recurring basis
Net Assets (Liabilities) as of beginning of period	$ (4)	$ (40)	$ 24	$ (36)
Transfers into Level 3 from Level 2	0	1	0	0
Transfers from Level 3 into Level 2	0	(4)	0	2
Total gains (losses):
Included in earnings	39	10	26	(21)
Recorded in regulatory assets/liabilities	3	(3)	14	9
Purchases, issuances, and settlements:
Purchases	0	0	2	1
Issuances	0	0	0	(2)
Settlements	(15)	(6)	(43)	5
Net Assets (Liabilities) as of end of period	23	(42)	23	(42)
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 September 30, 2015 and 2014 and reflected in Operating revenues and Fuel, purchased power and gas in DTE Energy's Consolidated Statements of Operations	12	6	(90)	(30)
DTE Electric
Fair value reconciliation of Level 3 assets and liabilities measured at fair value on a recurring basis
Net Assets (Liabilities) as of beginning of period	5	7	3	3
Total gains (losses):
Recorded in regulatory assets/liabilities	3	(3)	14	9
Purchases, issuances, and settlements:
Settlements	(3)	0	(12)	(8)
Net Assets (Liabilities) as of end of period	5	4	5	4
The amount of total gains (losses) included in Regulatory assets and liabilities attributed to the change in unrealized gains (losses) related to assets and liabilities held at September 30, 2015 and 2014 and reflected in DTE Electric's Consolidated Statements of Financial Position	1	(1)	5	4
Natural Gas
Fair value reconciliation of Level 3 assets and liabilities measured at fair value on a recurring basis
Net Assets (Liabilities) as of beginning of period	(8)	(20)	30	(52)
Transfers into Level 3 from Level 2	0	1	0	0
Transfers from Level 3 into Level 2	0	(4)	0	2
Total gains (losses):
Included in earnings	24	(2)	(11)	(45)
Recorded in regulatory assets/liabilities	0	0	0	0
Purchases, issuances, and settlements:
Purchases	0	0	0	0
Issuances	0	0	0	0
Settlements	5	(3)	2	67
Net Assets (Liabilities) as of end of period	21	(28)	21	(28)
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 September 30, 2015 and 2014 and reflected in Operating revenues and Fuel, purchased power and gas in DTE Energy's Consolidated Statements of Operations	18	(7)	(94)	(23)
Electricity
Fair value reconciliation of Level 3 assets and liabilities measured at fair value on a recurring basis
Net Assets (Liabilities) as of beginning of period	3	(27)	(5)	13
Transfers into Level 3 from Level 2	0	0	0	0
Transfers from Level 3 into Level 2	0	0	0	0
Total gains (losses):
Included in earnings	18	13	42	26
Recorded in regulatory assets/liabilities	0	0	0	0
Purchases, issuances, and settlements:
Purchases	0	0	2	1
Issuances	0	0	0	(2)
Settlements	(18)	(3)	(36)	(55)
Net Assets (Liabilities) as of end of period	3	(17)	3	(17)
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 September 30, 2015 and 2014 and reflected in Operating revenues and Fuel, purchased power and gas in DTE Energy's Consolidated Statements of Operations	(3)	14	8	(6)
Other
Fair value reconciliation of Level 3 assets and liabilities measured at fair value on a recurring basis
Net Assets (Liabilities) as of beginning of period	1	7	(1)	3
Transfers into Level 3 from Level 2	0	0	0	0
Transfers from Level 3 into Level 2	0	0	0	0
Total gains (losses):
Included in earnings	(3)	(1)	(5)	(2)
Recorded in regulatory assets/liabilities	3	(3)	14	9
Purchases, issuances, and settlements:
Purchases	0	0	0	0
Issuances	0	0	0	0
Settlements	(2)	0	(9)	(7)
Net Assets (Liabilities) as of end of period	(1)	3	(1)	3
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 September 30, 2015 and 2014 and reflected in Operating revenues and Fuel, purchased power and gas in DTE Energy's Consolidated Statements of Operations	$ (3)	$ (1)	$ (4)	$ (1)

Fair Value (Unobservable Inputs

Fair Value (Unobservable Inputs related to Level 3 Assets and Liabilities) (Details) $ in Millions	9 Months Ended	12 Months Ended
	Sep. 30, 2015USD ($)$ / MMBTU$ / MWh	Dec. 31, 2014USD ($)$ / MMBTU$ / MWh
Unobservable Inputs Valuation Techniques [Line Items]
Derivative asset, gross	$ 586	$ 1,178
Derivative liability, gross	(551)	(1,110)
Recurring | Level 3
Unobservable Inputs Valuation Techniques [Line Items]
Derivative asset, gross	106	142
Derivative liability, gross	(83)	(118)
Natural Gas
Unobservable Inputs Valuation Techniques [Line Items]
Derivative asset, gross	303	787
Derivative liability, gross	(277)	(718)
Natural Gas | Recurring | Level 3
Unobservable Inputs Valuation Techniques [Line Items]
Derivative asset, gross	54	92
Derivative liability, gross	$ (33)	$ (62)
Natural Gas | Minimum | Discounted cash flow valuation technique | Level 3
Unobservable Inputs Valuation Techniques [Line Items]
Forward basis price | $ / MMBTU	(1.73)	(2.28)
Natural Gas | Maximum | Discounted cash flow valuation technique | Level 3
Unobservable Inputs Valuation Techniques [Line Items]
Forward basis price | $ / MMBTU	6.57	7.83
Natural Gas | Weighted Average | Discounted cash flow valuation technique | Level 3
Unobservable Inputs Valuation Techniques [Line Items]
Forward basis price | $ / MMBTU	(0.11)	(0.22)
Electricity
Unobservable Inputs Valuation Techniques [Line Items]
Derivative asset, gross	$ 251	$ 342
Derivative liability, gross	(244)	(342)
Electricity | Recurring | Level 3
Unobservable Inputs Valuation Techniques [Line Items]
Derivative asset, gross	47	47
Derivative liability, gross	$ (44)	$ (52)
Electricity | Minimum | Discounted cash flow valuation technique | Level 3
Unobservable Inputs Valuation Techniques [Line Items]
Forward basis price | $ / MWh	(8)	(14)
Electricity | Maximum | Discounted cash flow valuation technique | Level 3
Unobservable Inputs Valuation Techniques [Line Items]
Forward basis price | $ / MWh	15	15
Electricity | Weighted Average | Discounted cash flow valuation technique | Level 3
Unobservable Inputs Valuation Techniques [Line Items]
Forward basis price | $ / MWh	1	4

Fair Value (Fair Value of Finan

Fair Value (Fair Value of Financial Instruments) (Details) - USD ($) $ in Millions	Sep. 30, 2015	Dec. 31, 2014
Carrying Amount
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Notes receivable, excluding capital leases	$ 34	$ 41
Dividends payable	131	122
Short-term borrowings	185	398
Long-term debt, excluding capital leases	9,310	8,606
Carrying Amount | DTE Electric
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Notes receivable, excluding capital leases	6	12
Short-term borrowings	46	50
Long-term debt, excluding capital leases	5,644	5,259
Carrying Amount | DTE Electric | Affiliates
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Notes receivable, excluding capital leases	4	8
Short-term borrowings	68	84
Fair Value | Level 1
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Notes receivable, excluding capital leases	0	0
Dividends payable	131	122
Short-term borrowings	0	0
Long-term debt, excluding capital leases	480	489
Fair Value | Level 1 | DTE Electric
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Notes receivable, excluding capital leases	0	0
Short-term borrowings	0	0
Long-term debt, excluding capital leases	0	0
Fair Value | Level 1 | DTE Electric | Affiliates
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Notes receivable, excluding capital leases	0	0
Short-term borrowings	0	0
Fair Value | Level 2
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Notes receivable, excluding capital leases	0	0
Dividends payable	0	0
Short-term borrowings	185	398
Long-term debt, excluding capital leases	8,289	8,308
Fair Value | Level 2 | DTE Electric
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Notes receivable, excluding capital leases	0	0
Short-term borrowings	46	50
Long-term debt, excluding capital leases	5,496	5,341
Fair Value | Level 2 | DTE Electric | Affiliates
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Notes receivable, excluding capital leases	0	0
Short-term borrowings	0	0
Fair Value | Level 3
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Notes receivable, excluding capital leases	34	41
Dividends payable	0	0
Short-term borrowings	0	0
Long-term debt, excluding capital leases	1,186	706
Fair Value | Level 3 | DTE Electric
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Notes receivable, excluding capital leases	6	12
Short-term borrowings	0	0
Long-term debt, excluding capital leases	562	496
Fair Value | Level 3 | DTE Electric | Affiliates
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Notes receivable, excluding capital leases	4	8
Short-term borrowings	$ 68	$ 84

Fair Value (Fair Value of Nucle

Fair Value (Fair Value of Nuclear Decommissioning Trust Fund Assets) (Details) - USD ($) $ in Millions	Sep. 30, 2015	Dec. 31, 2014
Schedule of Available-for-sale Securities [Line Items]
Nuclear decommissioning trust funds	$ 1,199	$ 1,241
DTE Electric
Schedule of Available-for-sale Securities [Line Items]
Nuclear decommissioning trust funds	1,199	1,241
DTE Electric | Fermi 2
Schedule of Available-for-sale Securities [Line Items]
Nuclear decommissioning trust funds	1,175	1,221
DTE Electric | Fermi 1
Schedule of Available-for-sale Securities [Line Items]
Nuclear decommissioning trust funds	3	3
DTE Electric | Low-level radioactive waste
Schedule of Available-for-sale Securities [Line Items]
Nuclear decommissioning trust funds	21	17
DTE Electric | Nuclear decommissioning trust fund
Schedule of Available-for-sale Securities [Line Items]
Nuclear decommissioning trust funds	$ 1,199	$ 1,241

Fair Value (Gains and Losses an

Fair Value (Gains and Losses and Proceeds from the Sale of Securities by the Nuclear Trust Funds) (Details) - DTE Electric - Nuclear decommissioning trust fund - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Schedule of Available-for-sale Securities [Line Items]
Realized gains	$ 8	$ 8	$ 30	$ 24
Realized losses	(10)	(3)	(23)	(14)
Proceeds from sales of securities	$ 187	$ 177	$ 627	$ 652

Fair Value (Fair Value and Unre

Fair Value (Fair Value and Unrealized Gains for the Nuclear Decommissioning Trust Funds) (Details) - DTE Electric - Nuclear decommissioning trust fund - USD ($) $ in Millions	Sep. 30, 2015	Dec. 31, 2014
Schedule of Available-for-sale Securities [Line Items]
Equity securities, fair value	$ 708	$ 756
Debt securities, fair value	484	474
Cash and cash equivalents	7	11
Fair Value	1,199	1,241
Equity securities, unrealized gains	169	204
Debt securities, unrealized gains	18	21
Unrealized Gains	187	225
Equity securities, unrealized losses	(74)	(39)
Debt securities, unrealized losses	(2)	(2)
Unrealized Losses	$ (76)	$ (41)

Fair Value (Details Textuals)

Fair Value (Details Textuals) - USD ($)	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014	Dec. 31, 2014
Fair Value, Option, Quantitative Disclosures [Line Items]
Assets Level 1 to 2	$ 0	$ 0	$ 0	$ 0
Assets Level 2 to 1	0	0	0	0
Liabilities Level 1 to 2	0	0	0	0
Liabilities Level 2 to 1	0	0	0	0
Trading securities realized gain (loss)			(2,000,000)	9,000,000
Accumulated Net Unrealized Investment Gain (Loss)
Fair Value, Option, Quantitative Disclosures [Line Items]
Unrealized losses on available for sale securities	0	0	0	0
DTE Electric
Fair Value, Option, Quantitative Disclosures [Line Items]
Transfers between Level 3			0	0
Trading securities realized gain (loss)			(2,000,000)	8,000,000
DTE Electric | Accumulated Net Unrealized Investment Gain (Loss)
Fair Value, Option, Quantitative Disclosures [Line Items]
Unrealized losses on available for sale securities	0	$ 0	0	$ 0
DTE Electric | Nuclear decommissioning trust fund
Fair Value, Option, Quantitative Disclosures [Line Items]
Cash and cash equivalents	7,000,000		$ 7,000,000		$ 11,000,000
Average maturity of debt securities			6 years		7 years
Recurring
Fair Value, Option, Quantitative Disclosures [Line Items]
Cash and cash equivalents	14,000,000		$ 14,000,000		$ 112,000,000
Recurring | DTE Electric
Fair Value, Option, Quantitative Disclosures [Line Items]
Cash and cash equivalents	8,000,000		8,000,000		104,000,000
Restricted assets | Recurring
Fair Value, Option, Quantitative Disclosures [Line Items]
Cash and cash equivalents	6,000,000		6,000,000		105,000,000
Restricted assets | Recurring | DTE Electric
Fair Value, Option, Quantitative Disclosures [Line Items]
Cash and cash equivalents					96,000,000
Other investments | Recurring
Fair Value, Option, Quantitative Disclosures [Line Items]
Cash and cash equivalents	8,000,000		8,000,000		7,000,000
Other investments | Recurring | DTE Electric
Fair Value, Option, Quantitative Disclosures [Line Items]
Cash and cash equivalents					8,000,000
Other investments | Recurring | Equity
Fair Value, Option, Quantitative Disclosures [Line Items]
Other investments	$ 145,000,000		$ 145,000,000		$ 150,000,000

Financial and Other Derivativ54

Financial and Other Derivative Instruments (Fair Value of Derivative Instruments) (Details) - USD ($) $ in Millions	Sep. 30, 2015	Dec. 31, 2014
Derivatives, Fair Value [Line Items]
Derivative asset, gross	$ 586	$ 1,178
Derivative liability, gross	(551)	(1,110)
Not Designated as Hedging Instrument
Derivatives, Fair Value [Line Items]
Derivative asset, gross	586	1,178
Derivative liability, gross	(551)	(1,110)
DTE Electric | Not Designated as Hedging Instrument
Derivatives, Fair Value [Line Items]
Derivative asset, gross	5	3
Foreign currency exchange contracts | Not Designated as Hedging Instrument
Derivatives, Fair Value [Line Items]
Derivative asset, gross	10	4
Derivative liability, gross	(7)	(5)
Natural Gas
Derivatives, Fair Value [Line Items]
Derivative asset, gross	303	787
Derivative liability, gross	(277)	(718)
Natural Gas | Not Designated as Hedging Instrument
Derivatives, Fair Value [Line Items]
Derivative asset, gross	303	787
Derivative liability, gross	(277)	(718)
Electricity
Derivatives, Fair Value [Line Items]
Derivative asset, gross	251	342
Derivative liability, gross	(244)	(342)
Electricity | Not Designated as Hedging Instrument
Derivatives, Fair Value [Line Items]
Derivative asset, gross	251	342
Derivative liability, gross	(244)	(342)
Other
Derivatives, Fair Value [Line Items]
Derivative asset, gross	22	45
Derivative liability, gross	(23)	(45)
Other | Not Designated as Hedging Instrument
Derivatives, Fair Value [Line Items]
Derivative asset, gross	22	45
Derivative liability, gross	(23)	(45)
Financial transmission rights | DTE Electric | Not Designated as Hedging Instrument
Derivatives, Fair Value [Line Items]
Derivative asset, gross	5	3
Current derivative asset
Derivatives, Fair Value [Line Items]
Derivative asset, gross	448	1,083
Current derivative liability
Derivatives, Fair Value [Line Items]
Derivative liability, gross	(419)	(1,041)
Noncurrent derivative asset
Derivatives, Fair Value [Line Items]
Derivative asset, gross	138	95
Noncurrent derivative liability
Derivatives, Fair Value [Line Items]
Derivative liability, gross	$ (132)	$ (69)

Financial and Other Derivativ55

Financial and Other Derivative Instruments Financial and Other Derivative Instruments (Netting Offsets of Derivative Assets and Liabilities) (Details) - USD ($) $ in Millions	Sep. 30, 2015	Dec. 31, 2014
Offsetting Assets [Line Items]
Gross Amounts of Recognized Assets	$ 586	$ 1,178
Gross Amounts Offset in the Consolidated Statements of Financial Position	(448)	(1,006)
Net Amounts of Assets Presented in the Consolidated Statements of Financial Position	138	172
Gross Amounts of Recognized (Liabilities)	(551)	(1,110)
Gross Amounts Offset in the Consolidated Statements of Financial Position	468	1,025
Net Amounts of (Liabilities) Presented in the Consolidated Statements of Financial Position	(83)	(85)
Natural Gas
Offsetting Assets [Line Items]
Gross Amounts of Recognized Assets	303	787
Gross Amounts Offset in the Consolidated Statements of Financial Position	(244)	(681)
Net Amounts of Assets Presented in the Consolidated Statements of Financial Position	59	106
Gross Amounts of Recognized (Liabilities)	(277)	(718)
Gross Amounts Offset in the Consolidated Statements of Financial Position	249	679
Net Amounts of (Liabilities) Presented in the Consolidated Statements of Financial Position	(28)	(39)
Electricity
Offsetting Assets [Line Items]
Gross Amounts of Recognized Assets	251	342
Gross Amounts Offset in the Consolidated Statements of Financial Position	(179)	(280)
Net Amounts of Assets Presented in the Consolidated Statements of Financial Position	72	62
Gross Amounts of Recognized (Liabilities)	(244)	(342)
Gross Amounts Offset in the Consolidated Statements of Financial Position	190	298
Net Amounts of (Liabilities) Presented in the Consolidated Statements of Financial Position	(54)	(44)
Other
Offsetting Assets [Line Items]
Gross Amounts of Recognized Assets	22	45
Gross Amounts Offset in the Consolidated Statements of Financial Position	(17)	(42)
Net Amounts of Assets Presented in the Consolidated Statements of Financial Position	5	3
Gross Amounts of Recognized (Liabilities)	(23)	(45)
Gross Amounts Offset in the Consolidated Statements of Financial Position	22	45
Net Amounts of (Liabilities) Presented in the Consolidated Statements of Financial Position	(1)	0
Other derivative contract
Offsetting Assets [Line Items]
Gross Amounts of Recognized Assets	10	4
Gross Amounts Offset in the Consolidated Statements of Financial Position	(8)	(3)
Net Amounts of Assets Presented in the Consolidated Statements of Financial Position	2	1
Gross Amounts of Recognized (Liabilities)	(7)	(5)
Gross Amounts Offset in the Consolidated Statements of Financial Position	7	3
Net Amounts of (Liabilities) Presented in the Consolidated Statements of Financial Position	$ 0	$ (2)

Financial and Other Derivativ56

Financial and Other Derivative Instruments Financial and Other Derivative Instruments (Netting Offsets Reconciliation to Balance Sheet) (Details) - USD ($)	Sep. 30, 2015	Dec. 31, 2014
Derivative Assets
Derivative asset, gross	$ 586,000,000	$ 1,178,000,000
Collateral adjustment	(1,000,000)	0
Derivative assets, current	90,000,000	128,000,000
Derivative assets, noncurrent	48,000,000	44,000,000
Derivative Liabilities
Derivative liability, gross	(551,000,000)	(1,110,000,000)
Collateral adjustment	21,000,000	19,000,000
Derivative liabilities, current	(56,000,000)	(77,000,000)
Derivative liabilities, noncurrent	(27,000,000)	(8,000,000)
Current derivative asset
Derivative Assets
Derivative asset, gross	448,000,000	1,083,000,000
Counterparty netting	(358,000,000)	(955,000,000)
Collateral adjustment	0	0
Noncurrent derivative asset
Derivative Assets
Derivative asset, gross	138,000,000	95,000,000
Counterparty netting	(89,000,000)	(51,000,000)
Collateral adjustment	(1,000,000)	0
Current derivative liability
Derivative Liabilities
Derivative liability, gross	(419,000,000)	(1,041,000,000)
Counterparty netting	358,000,000	955,000,000
Collateral adjustment	5,000,000	9,000,000
Noncurrent derivative liability
Derivative Liabilities
Derivative liability, gross	(132,000,000)	(69,000,000)
Counterparty netting	89,000,000	51,000,000
Collateral adjustment	$ 16,000,000	$ 10,000,000

Financial and Other Derivativ57

Financial and Other Derivative Instruments (Effect of Derivatives not Designated as Hedging Instruments on the Consolidated Statement of Operations) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Derivative Instruments, Gain (Loss) [Line Items]
Gain (Loss) Recognized in Income on Derivatives	$ 42	$ (16)	$ (8)	$ 106
Foreign currency exchange contracts | Operating Revenue
Derivative Instruments, Gain (Loss) [Line Items]
Gain (Loss) Recognized in Income on Derivatives	1	(1)	2	(2)
Natural Gas | Operating Revenue
Derivative Instruments, Gain (Loss) [Line Items]
Gain (Loss) Recognized in Income on Derivatives	55	(38)	(75)	(10)
Natural Gas | Fuel, purchased power, and gas
Derivative Instruments, Gain (Loss) [Line Items]
Gain (Loss) Recognized in Income on Derivatives	(24)	12	9	23
Electricity | Operating Revenue
Derivative Instruments, Gain (Loss) [Line Items]
Gain (Loss) Recognized in Income on Derivatives	14	12	60	100
Other | Operating Revenue
Derivative Instruments, Gain (Loss) [Line Items]
Gain (Loss) Recognized in Income on Derivatives	$ (4)	$ (1)	$ (4)	$ (5)

Financial and Other Derivativ58

Financial and Other Derivative Instruments (Cumulative Gross Volume of Derivative Contracts Outstanding) (Details)	Sep. 30, 2015CADMWhgalMMBTU
Natural Gas (MMBtu)
Derivative [Line Items]
Number of units | MMBTU	1,083,436,935
Electricity (MWh)
Derivative [Line Items]
Number of units | MWh	22,421,752
Oil (Gallons)
Derivative [Line Items]
Number of units	23,520,000
Foreign currency exchange contracts (Canadian dollars)
Derivative [Line Items]
Derivative fair value | CAD	CAD 42,420,220

Financial and Other Derivativ59

Financial and Other Derivative Instruments (Details Textuals) - USD ($)	Sep. 30, 2015	Dec. 31, 2014
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Letters of credit that could be used to offset net derivative liabilities	$ 0	$ 7,000,000
Letters of credit received that could be used to offset net derivative assets	1,000,000	5,000,000
Cash collateral posted, net of cash collateral received	27,000,000	61,000,000
Collateral adjustment on derivative assets	1,000,000	0
Collateral adjustment on derivative liabilities	21,000,000	19,000,000
Cash collateral paid	8,000,000	44,000,000
Cash collateral received	1,000,000	$ 2,000,000
Additional collateral, aggregate fair value	420,000,000
Derivative net liability position aggregate fair value	516,000,000
Collateral already posted fair value	0
Derivative net asset position, fair value	430,000,000
Remaining amount of offsets to derivative net liability positions for hard and soft trigger provisions	$ 85,000,000

Long-Term Debt (Debt Issuances)

Long-Term Debt (Debt Issuances) (Details)	Sep. 30, 2015USD ($)
Debt Instrument [Line Items]
Face amount	$ 965,000,000
Senior Notes | June 2015 3.30% Senior Notes Maturing 2022
Debt Instrument [Line Items]
Interest Rate	3.30%
Face amount	$ 300,000,000
DTE Electric | Mortgages | March 2015 3.70% Mortgage Bonds Maturing 2045
Debt Instrument [Line Items]
Interest Rate	3.70%
Face amount	$ 500,000,000
DTE Gas | Mortgages | August 2015 3.35% Mortgage Bonds Maturing in 2027
Debt Instrument [Line Items]
Interest Rate	3.35%
Face amount	$ 40,000,000
DTE Gas | Mortgages | August 2015 4.21% Mortgage Bonds Maturing in 2045
Debt Instrument [Line Items]
Interest Rate	4.21%
Face amount	$ 125,000,000

Long-Term Debt (Debt Redemption

Long-Term Debt (Debt Redemptions) (Details) $ in Millions	9 Months Ended
	Sep. 30, 2015USD ($)
Debt Instrument [Line Items]
Debt redemption amount	$ 260
Securitization Bonds | DTE Electric | March 2015 Securitization Bonds 6.62% due 2015
Debt Instrument [Line Items]
Interest Rate	6.62%
Debt redemption amount	$ 105
Mortgages | DTE Electric | March 2015 7.904% Mortgage Bonds Due 2016
Debt Instrument [Line Items]
Interest Rate	7.904%
Debt redemption amount	$ 10
Senior Notes | DTE Gas | September 2015 5.94% Senior Notes Due 2015
Debt Instrument [Line Items]
Interest Rate	5.94%
Debt redemption amount	$ 140
Other Long Term Debt | Various Other Long Term Debt Due 2015
Debt Instrument [Line Items]
Debt redemption amount	$ 5

Short-Term Credit Arrangement62

Short-Term Credit Arrangements and Borrowings (Details)	Sep. 30, 2015USD ($)
Availability under combined facilities
Maximum borrowing capacity	$ 2,070,000,000
Amounts outstanding	370,000,000
Net availability	1,700,000,000
DTE Energy
Availability under combined facilities
Maximum borrowing capacity	1,370,000,000
Amounts outstanding	196,000,000
Net availability	1,174,000,000
DTE Electric
Availability under combined facilities
Maximum borrowing capacity	400,000,000
Amounts outstanding	46,000,000
Net availability	354,000,000
DTE Gas
Availability under combined facilities
Maximum borrowing capacity	300,000,000
Amounts outstanding	128,000,000
Net availability	172,000,000
Letter of Credit
Availability under combined facilities
Amounts outstanding	185,000,000
Letter of Credit | DTE Energy
Availability under combined facilities
Amounts outstanding	185,000,000
Letter of Credit | DTE Electric
Availability under combined facilities
Amounts outstanding	0
Letter of Credit | DTE Gas
Availability under combined facilities
Amounts outstanding	0
Letter of Credit | Unsecured letter of credit facility, expiring in February 2017
Availability under combined facilities
Maximum borrowing capacity	100,000,000
Letter of Credit | Unsecured letter of credit facility, expiring in February 2017 | DTE Energy
Availability under combined facilities
Maximum borrowing capacity	100,000,000
Letter of Credit | Unsecured letter of credit facility, expiring in February 2017 | DTE Electric
Availability under combined facilities
Maximum borrowing capacity	0
Letter of Credit | Unsecured letter of credit facility, expiring in February 2017 | DTE Gas
Availability under combined facilities
Maximum borrowing capacity	0
Letter of Credit | Unsecured letter of credit facility, expiring in September 2017
Availability under combined facilities
Maximum borrowing capacity	70,000,000
Letter of Credit | Unsecured letter of credit facility, expiring in September 2017 | DTE Energy
Availability under combined facilities
Maximum borrowing capacity	70,000,000
Letter of Credit | Unsecured letter of credit facility, expiring in September 2017 | DTE Electric
Availability under combined facilities
Maximum borrowing capacity	0
Letter of Credit | Unsecured letter of credit facility, expiring in September 2017 | DTE Gas
Availability under combined facilities
Maximum borrowing capacity	0
Revolving Credit Facility | Unsecured revolving credit facility, expiring April 2020
Availability under combined facilities
Maximum borrowing capacity	1,900,000,000
Revolving Credit Facility | Unsecured revolving credit facility, expiring April 2020 | DTE Energy
Availability under combined facilities
Maximum borrowing capacity	1,200,000,000
Revolving Credit Facility | Unsecured revolving credit facility, expiring April 2020 | DTE Electric
Availability under combined facilities
Maximum borrowing capacity	400,000,000
Revolving Credit Facility | Unsecured revolving credit facility, expiring April 2020 | DTE Gas
Availability under combined facilities
Maximum borrowing capacity	300,000,000
Commercial paper issuances
Availability under combined facilities
Amounts outstanding	185,000,000
Commercial paper issuances | DTE Energy
Availability under combined facilities
Amounts outstanding	11,000,000
Commercial paper issuances | DTE Electric
Availability under combined facilities
Amounts outstanding	46,000,000
Commercial paper issuances | DTE Gas
Availability under combined facilities
Amounts outstanding	$ 128,000,000

Short-Term Credit Arrangement63

Short-Term Credit Arrangements and Borrowings (Details Textuals)	1 Months Ended
	Sep. 30, 2015USD ($)	Dec. 31, 2014USD ($)
Short-term Debt [Line Items]
Maximum borrowing capacity	$ 2,070,000,000
Other outstanding letters of credit	$ 370,000,000
Maximum
Short-term Debt [Line Items]
Ratio of indebtedness to net capital	0.65
Letter of Credit
Short-term Debt [Line Items]
Other outstanding letters of credit	$ 185,000,000
DTE Energy
Short-term Debt [Line Items]
Maximum borrowing capacity	$ 1,370,000,000
Ratio of indebtedness to net capital	0.50
Other outstanding letters of credit	$ 196,000,000
DTE Energy | Letter of Credit
Short-term Debt [Line Items]
Other outstanding letters of credit	185,000,000
DTE Energy | Demand Financing Agreement
Short-term Debt [Line Items]
Maximum borrowing capacity, financing agreement	100,000,000
Maximum additional margin financing	50,000,000
Amount outstanding	70,000,000	$ 37,000,000
DTE Energy | Demand Financing Agreement Plus Letter of Credit
Short-term Debt [Line Items]
Maximum borrowing capacity, financing agreement	125,000,000
DTE Electric
Short-term Debt [Line Items]
Maximum borrowing capacity	$ 400,000,000
Ratio of indebtedness to net capital	0.50
Other outstanding letters of credit	$ 46,000,000
DTE Electric | Letter of Credit
Short-term Debt [Line Items]
Other outstanding letters of credit	0
DTE Gas
Short-term Debt [Line Items]
Maximum borrowing capacity	$ 300,000,000
Ratio of indebtedness to net capital	0.48
Other outstanding letters of credit	$ 128,000,000
DTE Gas | Letter of Credit
Short-term Debt [Line Items]
Other outstanding letters of credit	0
Unsecured letter of credit facility, expiring in September 2017 | Letter of Credit
Short-term Debt [Line Items]
Maximum borrowing capacity	$ 70,000,000
Term of debt, years	2 years
Unsecured letter of credit facility, expiring in September 2017 | DTE Energy | Letter of Credit
Short-term Debt [Line Items]
Maximum borrowing capacity	$ 70,000,000
Unsecured letter of credit facility, expiring in September 2017 | DTE Electric | Letter of Credit
Short-term Debt [Line Items]
Maximum borrowing capacity	0
Unsecured letter of credit facility, expiring in September 2017 | DTE Gas | Letter of Credit
Short-term Debt [Line Items]
Maximum borrowing capacity	0
Other outstanding letters of credit | DTE Energy | Letter of Credit
Short-term Debt [Line Items]
Other outstanding letters of credit	20,000,000
Demand Financing Agreement | DTE Energy | Letter of Credit
Short-term Debt [Line Items]
Maximum borrowing capacity, financing agreement	$ 25,000,000

Commitments and Contingencies (

Commitments and Contingencies (Details Textuals)	Jan. 13, 2015USD ($)	May. 16, 2014kWh	May. 31, 2014	May. 15, 2014$ / MWh	Sep. 30, 2015USD ($)employeefacilityinstancefacilities	Dec. 31, 2014USD ($)	Dec. 31, 2010instance	Jul. 31, 2009facility
Loss Contingencies [Line Items]
Number of NOVs | instance							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					15,000,000
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
Commitment amount					7,400,000,000
Future commitments					$ 2,500,000,000
Represented employees
Loss Contingencies [Line Items]
Entity number of employees | employee					4,900
Synthetic Fuel
Loss Contingencies [Line Items]
Term after expiration of statutes of limitations					90 days
Maximum potential liability					$ 850,000,000
Emissions
Loss Contingencies [Line Items]
Term after expiration of statutes of limitations					90 days
Maximum potential liability					$ 238,000,000
Other Guarantees
Loss Contingencies [Line Items]
Maximum potential liability					66,000,000
Performance Surety Bonds
Loss Contingencies [Line Items]
Performance bonds outstanding					$ 49,000,000
DTE Electric
Loss Contingencies [Line Items]
EPA is alleging detroit edison power plants violated new source performance standards | facility								5
Number of NOVs/FOVs currently being discussed with the EPA | instance					2
Environmental capital expenditures through prior year end						$ 2,200,000,000
Environmental capital expenditures in current year					$ 100,000,000
Environmental capital expenditures in future years					$ 50,000,000
Time period to complete studies on cooling water intake structures impacts on fish - EPA ruling			3 years
Number of former MGP sites | facility					3
Accrual for environmental loss contingencies, gross					$ 9,000,000	10,000,000
Waiting period of policy					84 days
Insurance coverage for extra expense when to necessitate power plant when 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
Total limit for property damage for non-nuclear events					2,000,000,000
Limit for property damage for non-nuclear events aggregate of extra expenses					$ 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 terrorism loss	$ 3,200,000,000
Amount per event loss associated with nuclear power plants					$ 46,000,000
Maintenance of public liability insurance for nuclear power plants					375,000,000
Aggregate limit of liabilities arises from terrorist act outside scope of trials subject to one industry					300,000,000
Deferred premium charged levied against each licensed nuclear facility					127,000,000
Maximum deferred premium charges per year					19,000,000
Company obligated to pay DOE fee of Fermi 2 electricity generated and sold | $ / MWh				1
New DOE fee for nuclear waste | kWh		0
Commitment amount					2,200,000,000
Future commitments					$ 1,800,000,000
DTE Electric | Represented employees
Loss Contingencies [Line Items]
Entity number of employees | employee					2,600
DTE Electric | Coal Combustion Residual Rule
Loss Contingencies [Line Items]
Period in which new facilities are expected to be built, years					7 years
Estimated cost of compliance					$ 190,000,000
DTE Gas
Loss Contingencies [Line Items]
Number of former MGP sites | facility					14
Accrual for environmental loss contingencies, gross					$ 23,000,000	$ 24,000,000
Period gas utility can amortize MGP costs					10 years
DTE Gas | Cleanup completed and site closed
Loss Contingencies [Line Items]
Number of former MGP sites | facility					5
DTE Gas | Complete closure expected by end of fiscal year
Loss Contingencies [Line Items]
Number of former MGP sites | facilities					2

Retirement Benefits and Trust65

Retirement Benefits and Trusteed Assets (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Pension Benefits
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Service cost	$ 27	$ 19	$ 76	$ 62
Interest cost	52	54	158	159
Expected return on plan assets	(74)	(69)	(222)	(205)
Amortization of net actuarial loss	51	42	154	118
Amortization of prior service credit	0	0	0	0
Net periodic benefit cost (credit)	56	46	166	134
Pension Benefits | DTE Electric
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Service cost	21	14	59	48
Interest cost	39	41	120	121
Expected return on plan assets	(53)	(48)	(158)	(145)
Amortization of net actuarial loss	36	30	110	83
Amortization of prior service credit	0	0	1	1
Net periodic benefit cost (credit)	43	37	132	108
Other Postretirement Benefits
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Service cost	8	8	25	26
Interest cost	20	22	61	67
Expected return on plan assets	(33)	(31)	(98)	(92)
Amortization of net actuarial loss	10	4	32	15
Amortization of prior service credit	(31)	(36)	(94)	(108)
Net periodic benefit cost (credit)	(26)	(33)	(74)	(92)
Other Postretirement Benefits | DTE Electric
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Service cost	6	6	19	19
Interest cost	15	17	46	51
Expected return on plan assets	(23)	(21)	(68)	(63)
Amortization of net actuarial loss	8	3	24	11
Amortization of prior service credit	(24)	(27)	(71)	(82)
Net periodic benefit cost (credit)	$ (18)	$ (22)	$ (50)	$ (64)

Retirement Benefits and Trust66

Retirement Benefits and Trusteed Assets Retirement Benefits and Trusteed Assets (VEBA Trust) (Details) - USD ($) $ / shares in Units, $ in Millions	Feb. 17, 2015	Sep. 30, 2015
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Contribution of common stock to VEBA Trust		$ 117
Other Postretirement Benefits
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Contribution of common stock to VEBA Trust		$ 117
VEBA Trust | Other Postretirement Benefits
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Contributions to Master VEBA Trust, Number of shares	1,427,835
Price Per Share	$ 81.91
Contribution of common stock to VEBA Trust	$ 117

Retirement Benefits and Trust67

Retirement Benefits and Trusteed Assets (Details Textuals) - USD ($)	Feb. 17, 2015	Sep. 30, 2015
Defined Benefit Plans and Other Postretirement Benefit Plans [Line Items]
Contribution of common stock to VEBA Trust		$ 117,000,000
Pension Benefits
Defined Benefit Plans and Other Postretirement Benefit Plans [Line Items]
Contributions by Employer		175,000,000
Pension Benefits | DTE Electric
Defined Benefit Plans and Other Postretirement Benefit Plans [Line Items]
Contributions by Employer		145,000,000
Other Postretirement Benefits
Defined Benefit Plans and Other Postretirement Benefit Plans [Line Items]
Contribution of common stock to VEBA Trust		117,000,000
VEBA Trust | Other Postretirement Benefits
Defined Benefit Plans and Other Postretirement Benefit Plans [Line Items]
Contribution of common stock to VEBA Trust	$ 117,000,000
VEBA Trust | Other Postretirement Benefits | DTE Gas
Defined Benefit Plans and Other Postretirement Benefit Plans [Line Items]
Contributions by Employer		24,000,000
Maximum | Other Postretirement Benefits | DTE Electric
Defined Benefit Plans and Other Postretirement Benefit Plans [Line Items]
Estimated Future Employer Contributions in Current Fiscal Year		$ 60,000,000

Stock-Based Compensation (Compo

Stock-Based Compensation (Components of Stock Based Compensation) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Components of stock-based compensation [Abstract]
Stock-based compensation expense	$ 12	$ 22	$ 32	$ 72
Tax benefit	5	8	13	27
Stock-based compensation cost capitalized in Property, plant, and equipment	$ 2	$ 4	$ 5	$ 11

Stock-Based Compensation (Stock

Stock-Based Compensation (Stock Option Activity) (Details) $ / shares in Units, $ in Millions	9 Months Ended
	Sep. 30, 2015USD ($)$ / sharesshares
Number of Options (in shares):
Options outstanding at December 31, 2014 | shares	444,278
Exercised | shares	(178,017)
Forfeited or expired | shares	(3,979)
Options outstanding at September 30, 2015 | shares	262,282
Options exercisable at September 30, 2015 | shares	262,282
Weighted Average Exercise Price (in dollars per share):
Options outstanding at December 31, 2014	$ 43.56
Exercised	45.07
Forfeited or expired	44.72
Options outstanding at September 30, 2015	42.52
Options exercisable at September 30, 2015	$ 42.52
Aggregate Intrinsic Value - Options outstanding | $	$ 9
Aggregate Intrinsic Value - Options exercisable | $	$ 9

Stock-Based Compensation (Restr

Stock-Based Compensation (Restricted Stock) (Details) - Restricted Stock	9 Months Ended
	Sep. 30, 2015$ / sharesshares
Restricted Stock (in shares)
Balance at December 31, 2014 | shares	416,318
Grants | shares	143,800
Forfeitures | shares	(8,975)
Vested and issued | shares	(158,920)
Balance at September 30, 2015 | shares	392,223
Weighted Average Grant Date Fair Value (in dollars per share)
Balance at December 31, 2014	$ 62.82
Grants	83.44
Forfeitures	73.62
Vested and issued	55.36
Balance at September 30, 2015	$ 73.15

Stock-Based Compensation (Perfo

Stock-Based Compensation (Performance Share Awards Activity) (Details) - Performance Shares	9 Months Ended
	Sep. 30, 2015$ / sharesshares
Performance Shares (in shares)
Balance at December 31, 2014 | shares	1,554,697
Grants | shares	454,654
Forfeitures | shares	(37,112)
Payouts | shares	(532,700)
Balance at September 30, 2015 | shares	1,439,539
Weighted Average Grant Date Fair Value (in dollars per share)
Balance at December 31, 2014	$ 69.32
Grants	83.86
Forfeitures	75.90
Payouts	0
Balance at September 30, 2015	$ 75.80

Stock-Based Compensation (Detai

Stock-Based Compensation (Details Textuals) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Remaining contractual life for exercisable shares			3 years 20 days
Intrinsic value			$ 7,000,000	$ 7,000,000
Stock option plan expense			0	0
Unrecognized compensation cost	$ 60,000,000		$ 60,000,000
Weighted average period for unrecognized compensation cost to be recognized			1 year 2 months 22 days
Performance Shares
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Vesting period			3 years
DTE Electric | DTE Energy
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Stock-based compensation	$ 7,000,000	$ 14,000,000	$ 20,000,000	$ 43,000,000

Segment and Related Informati73

Segment and Related Information (Financial Data - Operating Revenues including inter segment revenues) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Segment Reporting, Revenue Reconciling Item [Line Items]
Operating Revenues	$ 2,598	$ 2,595	$ 7,850	$ 9,223
Reconciliation and Eliminations
Segment Reporting, Revenue Reconciling Item [Line Items]
Operating Revenues	(223)	(230)	(660)	(655)
Electric | Operating Segments
Segment Reporting, Revenue Reconciling Item [Line Items]
Operating Revenues	1,386	1,358	3,737	4,049
Electric | Reconciliation and Eliminations
Segment Reporting, Revenue Reconciling Item [Line Items]
Operating Revenues	(9)	(8)	(27)	(22)
Gas | Operating Segments
Segment Reporting, Revenue Reconciling Item [Line Items]
Operating Revenues	153	149	1,018	1,182
Gas | Reconciliation and Eliminations
Segment Reporting, Revenue Reconciling Item [Line Items]
Operating Revenues	(1)	(1)	(2)	(5)
Gas Storage and Pipelines | Operating Segments
Segment Reporting, Revenue Reconciling Item [Line Items]
Operating Revenues	61	49	175	146
Gas Storage and Pipelines | Reconciliation and Eliminations
Segment Reporting, Revenue Reconciling Item [Line Items]
Operating Revenues	(1)	(1)	(7)	(9)
Power and Industrial Projects | Operating Segments
Segment Reporting, Revenue Reconciling Item [Line Items]
Operating Revenues	585	605	1,708	1,703
Power and Industrial Projects | Reconciliation and Eliminations
Segment Reporting, Revenue Reconciling Item [Line Items]
Operating Revenues	(204)	(211)	(599)	(593)
Energy Trading | Operating Segments
Segment Reporting, Revenue Reconciling Item [Line Items]
Operating Revenues	635	664	1,870	2,797
Energy Trading | Reconciliation and Eliminations
Segment Reporting, Revenue Reconciling Item [Line Items]
Operating Revenues	(7)	(8)	(23)	(24)
Corporate and Other | Operating Segments
Segment Reporting, Revenue Reconciling Item [Line Items]
Operating Revenues	1	0	2	1
Corporate and Other | Reconciliation and Eliminations
Segment Reporting, Revenue Reconciling Item [Line Items]
Operating Revenues	$ (1)	$ (1)	$ (2)	$ (2)

Segment and Related Informati74

Segment and Related Information (Financial Data - Net Income or Loss) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Net Income Attributable to DTE Energy Company/DTE Electric	$ 265	$ 156	$ 647	$ 606
Electric
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Net Income Attributable to DTE Energy Company/DTE Electric	214	135	449	400
Gas
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Net Income Attributable to DTE Energy Company/DTE Electric	(11)	(16)	93	109
Gas Storage and Pipelines
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Net Income Attributable to DTE Energy Company/DTE Electric	27	20	79	59
Power and Industrial Projects
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Net Income Attributable to DTE Energy Company/DTE Electric	32	38	73	66
Energy Trading
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Net Income Attributable to DTE Energy Company/DTE Electric	12	(22)	0	6
Corporate and Other
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Net Income Attributable to DTE Energy Company/DTE Electric	$ (9)	$ 1	$ (47)	$ (34)

Segment and Related Informati75

Segment and Related Information (Details Textuals) customer in Millions	Sep. 30, 2015customer
Segment Reporting [Abstract]
Number of electric utility customers	2.1
Number of gas utility customers	1.2