DTE Energy (DTE) 10-Q 25 Oct 13 2013 Q3 Quarterly report Financial data

DEI_Document

DEI Document	9 Months Ended
	Sep. 30, 2013
Entity Registrant Name	DTE ENERGY CO
Entity Central Index Key	936340
Current Fiscal Year End Date	-21
Entity Filer Category	Large Accelerated Filer
Document Type	10-Q
Document Period End Date	30-Sep-13
Document Fiscal Year Focus	2013
Document Fiscal Period Focus	Q3
Amendment Flag	FALSE
Entity Common Stock, Shares Outstanding	176,797,248

Consolidated_Statements_of_Ope

Consolidated Statements of Operations (Unaudited) (USD $)	3 Months Ended		9 Months Ended
In Millions, except Per Share data, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Operating Revenues	$2,387	$2,190	$7,128	$6,442
Operating Expenses
Fuel, purchased power and gas	967	761	2,931	2,347
Operation and maintenance	728	687	2,168	2,111
Depreciation, depletion and amortization	284	259	811	730
Taxes other than income	84	78	262	252
Asset (gains) and losses, reserves and impairments, net	-5	-1	-6	-10
Total operating expenses	2,058	1,784	6,166	5,430
Operating Income	329	406	962	1,012
Other (Income) and Deductions
Interest expense	106	109	327	331
Interest income	-2	-2	-7	-7
Other income	-58	-47	-148	-125
Other expenses	7	9	23	27
Total Other (Income) and Deductions	-53	-69	-195	-226
Income Before Income Taxes	276	337	767	786
Income Tax Expense	76	108	225	251
Income from Continuing Operations	200	229	542	535
Loss from Discontinued Operations, net of tax	0	1	0	0
Net Income	200	230	542	535
Less: Net Income Attributable to Noncontrolling Interests	2	3	5	6
Net Income Attributable to DTE Energy Company	$198	$227	$537	$529
Basic Earnings per Common Share
Total Basic Earnings per Common Share	$1.13	$1.32	$3.07	$3.09
Income from continuing operations	$1.13	$1.31	$3.07	$3.09
Loss from discontinued operations, net of tax	$0	$0.01	$0	$0
Diluted Earnings per Common Share
Total Diluted Earnings per Common Share	$1.13	$1.31	$3.07	$3.08
Income from continuing operations	$1.13	$1.30	$3.07	$3.08
Loss from discontinued operations, net of tax	$0	$0.01	$0	$0
Weighted Average Common Shares Outstanding
Basic	175	172	174	171
Diluted	176	172	175	171
Dividends Declared per Common Share	$0.66	$0.62	$1.93	$1.80

Consolidated_Statements_of_Com

Consolidated Statements of Comprehensive Income (Unaudited) (USD $)	3 Months Ended		9 Months Ended
In Millions, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Statement of Income and Comprehensive Income [Abstract]
Net Income	$200	$230	$542	$535
Benefit obligations:
Benefit obligations, net of tax	-2	-3	-7	-9
Net unrealized gains (losses) on derivatives:
Net unrealized gains on investments during the period, net of taxes of $1, $—, $1 and $—	1	0	1	1
Foreign currency translation, net of taxes of $—, $1, $(1) and $1	1	1	-1	1
Other Comprehensive income	4	4	7	11
Comprehensive income	204	234	549	546
Less: Comprehensive income attributable to noncontrolling interests	2	3	5	6
Comprehensive income attributable to DTE Energy Company	$202	$231	$544	$540

Consolidated_Statements_of_Com1

Consolidated Statements of Comprehensive Income (Unaudited) (Parenthetical) (USD $)	3 Months Ended		9 Months Ended
In Millions, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Other Comprehensive Income (Loss), Pension and Other Postretirement Benefit Plans, Benefit Plan Improvement, Tax	$2	$1	$4	$4
Other Comprehensive Income (Loss), Unrealized Gain (Loss) on Derivatives Arising During Period, Tax	1	0	1	0
Other Comprehensive Income (Loss), Foreign Currency Translation Gain (Loss) Arising During Period, Tax	$0	$1	($1)	$1

Consolidated_Statements_of_Fin

Consolidated Statements of Financial Position (Unaudited) (USD $)	Sep. 30, 2013	Dec. 31, 2012
In Millions, unless otherwise specified
Current Assets
Cash and cash equivalents	$71	$65
Restricted cash, principally Securitization	64	122
Accounts receivable (less allowance for doubtful accounts of $67 and $62, respectively)
Customer	1,239	1,336
Other	81	126
Inventories
Fuel and gas	467	527
Materials and supplies	258	234
Deferred income taxes	0	21
Derivative assets	72	108
Regulatory assets	49	182
Other	248	194
Total Current Assets	2,549	2,915
Investments
Nuclear decommissioning trust funds	1,139	1,037
Other	584	554
Total Investments	1,723	1,591
Property
Property, plant and equipment	24,795	23,631
Less accumulated depreciation, depletion and amortization	-9,284	-8,947
Property, plant and equipment, net	15,511	14,684
Other Assets
Goodwill	2,018	2,018
Regulatory assets	3,700	4,235
Securitized regulatory assets	280	413
Intangible Assets	122	135
Notes receivable	104	112
Derivative assets	26	39
Other	198	197
Total Noncurrent Assets	6,448	7,149
Total Assets	26,231	26,339
Current Liabilities
Accounts payable	866	848
Accrued interest	114	93
Dividends payable	116	107
Short-term borrowings	271	240
Current portion long-term debt, including capital leases	896	817
Derivative liabilities	58	125
Regulatory liabilities	230	89
Other	457	449
Total Current Liabilities	3,008	2,768
Long-Term Debt (net of current portion)
Mortgage bonds, notes and other	6,253	6,220
Securitization bonds	105	302
Junior subordinated debentures	480	480
Capital lease obligations	8	12
Total Long-Term Debt (net of current portion)	6,846	7,014
Other Liabilities
Deferred income taxes	3,290	3,191
Regulatory liabilities	907	1,031
Asset retirement obligations	1,800	1,719
Unamortized investment tax credit	49	56
Derivative liabilities	21	26
Accrued pension liability	1,254	1,498
Accrued postretirement liability	684	1,160
Nuclear decommissioning	172	159
Other	290	306
Total Noncurrent Liabilities	8,467	9,146
Equity
Common stock, without par value, 400,000,000 shares authorized, 176,797,248 and 172,351,680 shares issued and outstanding, respectively	3,885	3,587
Retained earnings	4,142	3,944
Accumulated other comprehensive loss	-151	-158
Total DTE Energy Company Equity	7,876	7,373
Noncontrolling interests	34	38
Total Equity	7,910	7,411
Total Liabilities and Equity	$26,231	$26,339

Consolidated_Statements_of_Fin1

Consolidated Statements of Financial Position (Unaudited) (Parenthetical) (Parentheticals) (USD $)	Sep. 30, 2013	Dec. 31, 2012
In Millions, except Share data, unless otherwise specified
Allowance for doubtful accounts	$67	$62
Common stock, par value	$0	$0
Common stock, shares authorized	400,000,000	400,000,000
Common stock, shares issued	176,797,248	172,351,680
Common stock, shares outstanding	176,797,248	172,351,680

Consolidated_Statements_of_Cas

Consolidated Statements of Cash Flows (Unaudited) (USD $)	9 Months Ended
In Millions, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012
Operating Activities
Net Income	$542	$535
Adjustments to reconcile net income to net cash from operating activities:
Depreciation, depletion and amortization	811	747
Nuclear fuel amortization	25	25
Allowance for equity funds used during construction	-10	-10
Deferred income taxes	162	96
Asset (gains) and losses, reserves and impairments, net	5	7
Changes in assets and liabilities:
Accounts receivable, net	177	237
Inventories	35	5
Accounts payable	-16	-35
Derivative assets and liabilities	-23	38
Accrued pension obligation	-44	-3
Accrued postretirement obligation	-191	-143
Regulatory assets and liabilities	327	286
Other assets	-62	-2
Other liabilities	-13	-40
Net cash from operating activities	1,715	1,729
Investing Activities
Plant and equipment expenditures b utility	-1,101	-1,008
Plant and equipment expenditures b non-utility	-270	-214
Proceeds from sale of assets	20	20
Restricted cash for debt redemption, principally Securitization	58	55
Proceeds from sale of nuclear decommissioning trust fund assets	40	48
Investment in nuclear decommissioning trust funds	-52	-61
Other	-32	-24
Net cash used for investing activities	-1,337	-1,184
Financing Activities
Issuance of long-term debt, net	768	495
Redemption of long-term debt	-855	-447
Short-term borrowings, net	31	-321
Issuance of common stock	29	29
Dividends on common stock	-329	-300
Other	-16	-10
Net cash used for financing activities	-372	-554
Net Increase (Decrease) in Cash and Cash Equivalents	6	-9
Cash and Cash Equivalents at Beginning of Period	65	68
Cash and Cash Equivalents at End of Period	71	59
Supplemental Disclosure of Non-Cash Information
Common stock issued for employee benefit and compensation plans	279	143
Change in capital expenditures not paid	$263	$184

Consolidated_Statements_of_Cha

Consolidated Statements of Changes in Equity (Unaudited) (USD $)	Total	Common Stock	Retained Earnings	Accumulated Other Comprehensive Loss	Accumulated Translation Adjustment [Member]	Accumulated Defined Benefit Plans Adjustment [Member]	Accumulated Net Unrealized Investment Gain (Loss) [Member]	Non-controlling Interest
In Millions, except Share data
Stockholders' Equity, Including Portion Attributable to Noncontrolling interest at Dec. 31, 2012	$7,411	$3,587	$3,944	($158)				$38
Beginning Balance, shares at Dec. 31, 2012	172,351,680	172,352,000
Net Income	542		537					5
Dividends declared on common stock	-339		-339
Stock Issued During Period, Shares, New Issues		439,000
Issuance of common stock, value	29	29
Contribution of Common Stock to Pension Plan Shares		3,026,000
Contribution of Common Stock to Pension Plan	200	200
Other Comprehensive Income (Loss), Net of Tax	7				-1	7	1
Stock-based compensation, distributions to noncontrolling interests and other, shares		980,000
Stock-based compensation, distributions to noncontrolling interests and other	60	69						-9
Stockholders' Equity, Including Portion Attributable to Noncontrolling interest at Sep. 30, 2013	7,910	3,885	4,142	-151				34
Ending Balance, shares at Sep. 30, 2013	176,797,248	176,797,000
Stockholders' Equity, Including Portion Attributable to Noncontrolling interest at Jun. 30, 2013
Net Income	200
Other Comprehensive Income (Loss), Net of Tax	4				-1	2	1
Stockholders' Equity, Including Portion Attributable to Noncontrolling interest at Sep. 30, 2013	$7,910			($151)
Ending Balance, shares at Sep. 30, 2013	176,797,248

Organization_and_Basis_of_Pres

Organization and Basis of Presentation (Notes)	9 Months Ended
	Sep. 30, 2013
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Organization, Consolidation and Presentation of Financial Statements Disclosure [Text Block]	ORGANIZATION AND BASIS OF PRESENTATION
	Corporate Structure
	DTE Energy owns the following businesses:
	•	DTE Electric, an electric utility engaged in the generation, purchase, distribution and sale of electricity to approximately 2.1 million customers in southeastern Michigan;
	•	DTE Gas, a natural gas utility engaged in the purchase, storage, transportation, distribution and sale of natural gas to approximately 1.2 million customers throughout Michigan and the sale of storage and transportation capacity; and
	•	Other businesses involved in 1) natural gas pipelines, gathering and storage; 2) power and industrial projects; and 3) energy marketing and trading operations.
	DTE Electric and DTE Gas are regulated by the MPSC. Certain activities of DTE Electric and DTE Gas, as well as various other aspects of businesses under DTE Energy are regulated by the FERC. In addition, the Company is regulated by other federal and state regulatory agencies including the NRC, the EPA and the MDEQ.
	References in this Report to “Company” or “DTE” are to DTE Energy and its subsidiaries, collectively.
	Basis of Presentation
	These Consolidated Financial Statements should be read in conjunction with the Notes to Consolidated Financial Statements included in the 2012 Annual Report on Form 10-K.
	The accompanying Consolidated Financial Statements are prepared using accounting principles generally accepted in the United States of America. These accounting principles require management to use estimates and assumptions that impact reported amounts of assets, liabilities, revenues and expenses, and the disclosure of contingent assets and liabilities. Actual results may differ from the Company’s estimates.
	The Consolidated Financial Statements are unaudited, but in the Company's opinion 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 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, 2013.
	Certain prior year balances were reclassified to match the current year's financial statement presentation.
	Principles of Consolidation
	The Company consolidates all majority-owned subsidiaries and investments in entities in which it has controlling influence. Non-majority owned investments are accounted for using the equity method when the Company is able to influence the operating policies of the investee. When the Company does not influence the operating policies of an investee, the cost method is used. These consolidated financial statements also reflect the Company's proportionate interests in certain jointly owned utility plants. The Company eliminates all intercompany balances and transactions.
	The Company evaluates whether an entity is a VIE whenever reconsideration events occur. The Company consolidates VIEs for which it is the primary beneficiary. If the Company is not the primary beneficiary and an ownership interest is held, the VIE is accounted for under the equity method of accounting. When assessing the determination of the primary beneficiary, the Company considers all relevant facts and circumstances, including: the power, through voting or similar rights, to direct the activities of the VIE that most significantly impact the VIE's economic performance and the obligation to absorb the expected losses and/or the right to receive the expected returns of the VIE. The Company performs ongoing reassessments of all VIEs to determine if the primary beneficiary status has changed.
	Legal entities within the Company's Power and Industrial Projects segment enter into long-term contractual arrangements with customers to supply energy-related products or services. The entities are generally designed to pass-through the commodity risk associated with these contracts to the customers, with the Company retaining operational and customer default risk. These entities generally are VIEs and consolidated when the Company is the primary beneficiary. In addition, we have interests in certain VIEs that we share control of all significant activities for those entities with our partners, and therefore are accounted for under the equity method.
	The Company has variable interests in VIEs through certain of its long-term purchase contracts. As of September 30, 2013, the carrying amount of assets and liabilities in the Consolidated Statements of Financial Position that relate to its variable interests under long-term purchase contracts are predominately related to working capital accounts and generally represent the amounts owed by the Company for the deliveries associated with the current billing cycle under the contracts. The Company has not provided any form of financial support associated with these long-term contracts. There is no significant potential exposure to loss as a result of its variable interests through these long-term purchase contracts.
	In 2001, DTE Electric financed a regulatory asset related to Fermi 2 and certain other regulatory assets through the sale of rate reduction bonds by a wholly-owned special purpose entity, Securitization. DTE Electric performs servicing activities including billing and collecting surcharge revenue for Securitization. This entity is a VIE and is consolidated by the Company.
	The maximum risk exposure for consolidated VIEs is reflected on the Company's Consolidated Statements of Financial Position. For non-consolidated VIEs, the maximum risk exposure is generally limited to its investment and amounts which it has guaranteed.
	The following table summarizes the major balance sheet items for consolidated VIEs as of September 30, 2013 and December 31, 2012. All assets and liabilities of a consolidated VIE are presented where it has been determined that a consolidated VIE has either (1) assets that can be used only to settle obligations of the VIE or (2) liabilities for which creditors do not have recourse to the general credit of the primary beneficiary. VIEs, in which the Company holds a majority voting interest and is the primary beneficiary, that meet the definition of a business and whose assets can be used for purposes other than the settlement of the VIE's obligations have been excluded from the table below.
		30-Sep-13						31-Dec-12
		Securitization		Other		Total		Securitization		Other		Total
		(In millions)
	ASSETS
	Cash and cash equivalents	$	—	$	10	$	10	$	—	$	10	$	10
	Restricted cash	44		7		51		102		7		109
	Accounts receivable	39		17		56		34		7		41
	Inventories	—		112		112		—		141		141
	Other current assets	—		1		1		—		1		1
	Property, plant and equipment	—		100		100		—		93		93
	Securitized regulatory assets	280		—		280		413		—		413
	Other assets	5		9		14		7		11		18
		$	368	$	256	$	624	$	556	$	270	$	826
	LIABILITIES
	Accounts payable and accrued current liabilities	$	2	$	35	$	37	$	11	$	14	$	25
	Current portion long-term debt, including capital leases	196		9		205		177		8		185
	Current regulatory liabilities	48		—		48		50		—		50
	Other current liabilities	—		3		3		—		4		4
	Mortgage bonds, notes and other	—		22		22		—		25		25
	Securitization bonds	105		—		105		302		—		302
	Capital lease obligations	—		7		7		—		11		11
	Other long-term liabilities	8		3		11		7		2		9
		$	359	$	79	$	438	$	547	$	64	$	611
	Amounts for non-consolidated VIEs as of September 30, 2013 and December 31, 2012 are as follows:
		30-Sep-13		December 31, 2012
		(In millions)
	Other investments	$	138	$	130
	Notes receivable	$	3	$	6

Significant_Accounting_Policie

Significant Accounting Policies (Notes)	9 Months Ended
	Sep. 30, 2013
Accounting Policies [Abstract]
Significant Accounting Policies [Text Block]	SIGNIFICANT ACCOUNTING POLICIES
	Comprehensive Income
	Comprehensive income is the change in common shareholders’ equity during a period from transactions and events from non-owner sources, including net income. As shown in the following tables, amounts recorded to accumulated other comprehensive loss for the three and nine months ended September 30, 2013 include unrealized gains and losses from derivatives accounted for as cash flow hedges, unrealized gains and losses on available-for-sale securities and the Company’s interest in other comprehensive income of equity investees, which comprise the net unrealized gains and losses on investments, changes in benefit obligations, consisting of deferred actuarial losses, prior service costs and transition amounts related to pension and other postretirement benefit plans, and foreign currency translation adjustments.
		Changes in Accumulated Other Comprehensive Loss by Component (a)
		For The Three Months Ended September 30, 2013
		Net Unrealized Gain/(Loss) on Derivatives			Net Unrealized Gain/(Loss) on Investments			Benefit Obligations (b)			Foreign Currency Translation			Total
		(In millions)
	Beginning balance, June 30, 2013	$	(4	)	$	(8	)	$	(143	)	$	—		$	(155	)
	Other comprehensive income before reclassifications	—			1			—			1			2
	Amounts reclassified from accumulated other comprehensive income	—			—			2			—			2
	Net current-period other comprehensive income	—			1			2			1			4
	Ending balance, September 30, 2013	$	(4	)	$	(7	)	$	(141	)	$	1		$	(151	)
		Changes in Accumulated Other Comprehensive Loss by Component (a)
		For The Nine Months Ended September 30, 2013
		Net Unrealized Gain/(Loss) on Derivatives			Net Unrealized Gain/(Loss) on Investments			Benefit Obligations (b)			Foreign Currency Translation			Total
		(In millions)
	Beginning balance, December 31, 2012	$	(4	)	$	(8	)	$	(148	)	$	2		$	(158	)
	Other comprehensive income before reclassifications	—			1			—			(1		)	—
	Amounts reclassified from accumulated other comprehensive income	—			—			7			—			7
	Net current-period other comprehensive income (loss)	—			1			7			(1		)	7
	Ending balance, September 30, 2013	$	(4	)	$	(7	)	$	(141	)	$	1		$	(151	)
	______________________________________
	(a)	All amounts are net of tax.
	(b)	The amounts reclassified from accumulated other comprehensive income are included in the computation of the net periodic pension cost (see Retirement Benefits and Trusteed Assets Note 13).
	Intangible Assets
	The Company has certain intangible assets relating to emission allowances, renewable energy credits and non-utility contracts as shown below:
		September 30,			December 31,
		2013			2012
		(In millions)
	Emission allowances	$	3		$	6
	Renewable energy credits	48			44
	Contract intangible assets	126			139
		177			189
	Less accumulated amortization	41			34
	Intangible assets, net	136			155
	Less current intangible assets	14			20
		$	122		$	135
	Emission allowances and renewable energy credits are charged to expense, using average cost, as the allowances and credits are consumed in the operation of the business. The Company amortizes contract intangible assets on a straight-line basis over the expected period of benefit, ranging from 3 to 30 years.
	Income Taxes
	The Company's effective tax rate from continuing operations for the three months ended September 30, 2013 was 28 percent as compared to 32 percent for the three months ended September 30, 2012. The Company's effective tax rate from continuing operations for the nine months ended September 30, 2013 was 29 percent as compared to 32 percent for the nine months ended September 30, 2012. The decrease in the effective tax rate in 2013 is due primarily to higher production tax credits.
	The Company had $3 million of unrecognized tax benefits at September 30, 2013, that, if recognized, would favorably impact its effective tax rate. The Company believes that it is possible that there will be a decrease in the unrecognized tax benefits of up to $1 million in the next twelve months.

Fair_Value_Notes

Fair Value (Notes)	9 Months Ended
	Sep. 30, 2013
Fair Value Disclosures [Abstract]
Fair Value Disclosure	FAIR VALUE
	Fair value is defined as the price that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date in a principal or most advantageous market. Fair value is a market-based measurement that is determined based on inputs, which refer broadly to assumptions that market participants use in pricing assets or liabilities. These inputs can be readily observable, market corroborated or generally unobservable inputs. The Company makes certain assumptions it believes that market participants would use in pricing assets or liabilities, including assumptions about risk, and the risks inherent in the inputs to valuation techniques. Credit risk of the Company and its counterparties is incorporated in the valuation of assets and liabilities through the use of credit reserves, the impact of which was immaterial at September 30, 2013 and December 31, 2012. The Company believes it uses valuation techniques that maximize the use of observable market-based inputs and minimize the use of unobservable inputs.
	A fair value hierarchy has been established that prioritizes the inputs to valuation techniques used to measure fair value in three broad levels. The fair value hierarchy gives the highest priority to quoted prices (unadjusted) in active markets for identical assets or liabilities (Level 1) and the lowest priority to unobservable inputs (Level 3). In some cases, the inputs used to measure fair value might fall in different levels of the fair value hierarchy. All assets and liabilities are required to be classified in their entirety based on the lowest level of input that is significant to the fair value measurement in its entirety. Assessing the significance of a particular input may require judgment considering factors specific to the asset or liability, and may affect the valuation of the asset or liability and its placement within the fair value hierarchy. The Company classifies fair value balances based on the fair value hierarchy defined as follows:
	•	Level 1 — Consists of unadjusted quoted prices in active markets for identical assets or liabilities that the Company has the ability to access as of the reporting date.
	•	Level 2 — Consists of inputs other than quoted prices included within Level 1 that are directly observable for the asset or liability or indirectly observable through corroboration with observable market data.
	•	Level 3 — Consists of unobservable inputs for assets or liabilities whose fair value is estimated based on internally developed models or methodologies using inputs that are generally less readily observable and supported by little, if any, market activity at the measurement date. Unobservable inputs are developed based on the best available information and subject to cost-benefit constraints.
	The following table presents assets and liabilities measured and recorded at fair value on a recurring basis as of September 30, 2013 and December 31, 2012:
		30-Sep-13																				31-Dec-12
		Level 1				Level 2				Level 3				Netting (a)				Net Balance				Level 1				Level 2			Level 3			Netting (a)			Net Balance
		(In millions)
	Assets:
	Cash equivalents (b)	$	—			$	68			$	—			$	—			$	68			$	—			$	123		$	—		$	—		$	123
	Nuclear decommissioning trusts	757				382				—				—				1,139				694				343			—			—			1,037
	Other investments (c) (d)	76				48				—				—				124				66				44			—			—			110
	Derivative assets:
	Commodity Contracts:
	Natural Gas	388				61				34				(474		)		9				555				66			24			(605		)	40
	Electricity	—				210				88				(216		)		82				—				226			134			(258		)	102
	Other	48				9				5				(55		)		7				6				3			2			(6		)	5
	Total derivative assets	436				280				127				(745		)		98				561				295			160			(869		)	147
	Total	$	1,269			$	778			$	127			$	(745	)		$	1,429			$	1,321			$	805		$	160		$	(869	)	$	1,417
	Liabilities:
	Derivative liabilities:
	Interest rate contracts	$	—			$	—			$	—			$	—			$	—			$	—			$	(1	)	$	—		$	—		$	(1	)
	Commodity Contracts:
	Natural Gas	(374		)		(49		)		(48		)		445				(26		)		(526		)		(73		)	(62		)	605			(56		)
	Electricity	—				(204		)		(83		)		236				(51		)		—				(240		)	(111		)	258			(93		)
	Other	(52		)		(5		)		—				55				(2		)		(6		)		(1		)	—			6			(1		)
	Total derivative liabilities	(426		)		(258		)		(131		)		736				(79		)		(532		)		(315		)	(173		)	869			(151		)
	Total	$	(426	)		$	(258	)		$	(131	)		$	736			$	(79	)		$	(532	)		$	(315	)	$	(173	)	$	869		$	(151	)
	Net Assets (Liabilities) at the end of the period	$	843			$	520			$	(4	)		$	(9	)		$	1,350			$	789			$	490		$	(13	)	$	—		$	1,266
	Assets:
	Current	$	400			$	285			$	94			$	(639	)		$	140			$	493			$	372		$	120		$	(754	)	$	231
	Noncurrent (e)	869				493				33				(106		)		1,289				828				433			40			(115		)	1,186
	Total Assets	$	1,269			$	778			$	127			$	(745	)		$	1,429			$	1,321			$	805		$	160		$	(869	)	$	1,417
	Liabilities:
	Current	$	(379	)		$	(189	)		$	(100	)		$	610			$	(58	)		$	(466	)		$	(269	)	$	(144	)	$	754		$	(125	)
	Noncurrent	(47		)		(69		)		(31		)		126				(21		)		(66		)		(46		)	(29		)	115			(26		)
	Total Liabilities	$	(426	)		$	(258	)		$	(131	)		$	736			$	(79	)		$	(532	)		$	(315	)	$	(173	)	$	869		$	(151	)
	Net Assets (Liabilities) at the end of the period	$	843			$	520			$	(4	)		$	(9	)		$	1,350			$	789			$	490		$	(13	)	$	—		$	1,266
	_______________________________________
	(a)	Amounts represent the impact of master netting agreements that allow the Company to net gain and loss positions and cash collateral held or placed with the same counterparties.
	(b)	At September 30, 2013, available-for-sale securities of $68 million included $51 million and $17 million of cash equivalents included in Restricted cash and Other investments, respectively, on the Consolidated Statements of Financial Position. At December 31, 2012, available-for-sale securities of $123 million, included $109 million and $14 million of cash equivalents included in Restricted cash and Other investments, respectively, on the Consolidated Statements of Financial Position.
	(c)	Excludes cash surrender value of life insurance investments.
	(d)	Available-for-sale equity securities of $6 million at September 30, 2013 and $5 million at December 31, 2012, are included in Other investments on the Consolidated Statements of Financial Position.
	(e)	Includes $124 million and $110 million at September 30, 2013 and December 31, 2012, respectively, of Other investments that are included in the Consolidated Statements of Financial Position in Other investments.
	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. The fair values of the shares in these investments are based upon observable market prices for similar securities and, therefore, have been categorized as Level 2 in the fair value hierarchy.
	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 which hold exchange-traded equity or debt securities are valued based on the underlying securities, using quoted prices in actively traded markets. Non-exchange-traded fixed income securities are valued based upon quotations available from brokers or pricing services. A primary price source is identified by asset type, class or issue for each security. The trustee monitors prices supplied by pricing services and may use a supplemental price source or change the primary price source of a given security if the trustee determines that another price source is considered to be preferable. DTE Energy has obtained an understanding of how these prices are derived, including the nature and observability of the inputs used in deriving such prices. Additionally, DTE Energy selectively corroborates the fair value of securities by comparison of market-based price sources. Investment policies and procedures are determined by the Company's Trust Investments Department which reports to the Company's Vice President and Treasurer.
	Derivative Assets and Liabilities
	Derivative assets and liabilities are comprised of physical and financial derivative contracts, including futures, forwards, options and swaps that are both exchange-traded and over-the-counter traded contracts. Various inputs are used to value derivatives depending on the type of contract and availability of market data. Exchange-traded derivative contracts are valued using quoted prices in active markets. DTE Energy considers the following criteria in determining whether a market is considered active: frequency in which pricing information is updated, variability in pricing between sources or over time and the availability of public information. Other derivative contracts are valued based upon a variety of inputs including commodity market prices, broker quotes, interest rates, credit ratings, default rates, market-based seasonality and basis differential factors. DTE Energy monitors the prices that are supplied by brokers and pricing services and may use a supplemental price source or change the primary price source of an index if prices become unavailable or another price source is determined to be more representative of fair value. DTE Energy has obtained an understanding of how these prices are derived. Additionally, DTE Energy selectively corroborates the fair value of its transactions by comparison of market-based price sources. Mathematical valuation models are used for derivatives for which external market data is not readily observable, such as contracts which extend beyond the actively traded reporting period. The Company has established a Risk Management Committee whose responsibilities include directly or indirectly ensuring all valuation methods are applied in accordance with predefined policies. The development and maintenance of our forward price curves has been assigned to our Risk Management Department, which is separate and distinct from the trading functions within the Company.
	The following tables present the fair value reconciliation of Level 3 assets and liabilities measured at fair value on a recurring basis for the three months and nine months ended September 30, 2013 and 2012:
		Three Months Ended September 30, 2013																Three Months Ended September 30, 2012
		Natural Gas				Electricity				Other				Total				Natural Gas				Electricity				Other			Total
		(In millions)
	Net Assets (Liabilities) as of June 30	$	(30	)		$	12			$	2			$	(16	)		$	2			$	50			$	5		$	57
	Transfers into Level 3	—				—				—				—				—				—				—			—
	Transfers out of Level 3	—				(1		)		—				(1		)		—				—				—			—
	Total gains (losses):
	Included in earnings	8				17				—				25				(43		)		12				1			(30		)
	Recorded in regulatory assets/liabilities	—				—				3				3				—				—				7			7
	Purchases, issuances and settlements:
	Settlements	8				(23		)		—				(15		)		(3		)		(38		)		(7		)	(48		)
Net Assets (Liabilities) as of September 30	$	(14	)		$	5			$	5			$	(4	)		$	(44	)		$	24			$	6		$	(14	)
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, 2013 and 2012 and reflected in Operating revenues and Fuel, purchased power and gas in the Consolidated Statements of Operations	$	(8	)		$	8			$	—			$	—			$	(43	)		$	5			$	1		$	(37	)
	Nine Months Ended September 30, 2013																Nine Months Ended September 30, 2012
	Natural Gas				Electricity				Other				Total				Natural Gas				Electricity				Other			Total
	(In millions)
Net Assets (Liabilities) as of December 31	$	(38	)		$	23			$	2			$	(13	)		$	6			$	32			$	6		$	44
Transfers into Level 3	—				—				—				—				1				28				—			29
Transfers out of Level 3	(2		)		—				—				(2		)		(2		)		—				—			(2		)
Total gains (losses):
Included in earnings	(1		)		44				—				43				(38		)		53				—			15
Recorded in regulatory assets/liabilities	—				—				7				7				—				—				12			12
Purchases, issuances and settlements:
Purchases	—				(1		)		—				(1		)		—				1				—			1
Settlements	27				(61		)		(4		)		(38		)		(11		)		(90		)		(12		)	(113		)
Net Assets (Liabilities) as of September 30	$	(14	)		$	5			$	5			$	(4	)		$	(44	)		$	24			$	6		$	(14	)
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, 2013 and 2012 and reflected in Operating revenues and Fuel, purchased power and gas in the Consolidated Statements of Operations	$	(14	)		$	36			$	—			$	22			$	(39	)		$	43			$	—		$	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. The following table shows transfers between the levels of the fair value hierarchy for the three months and nine months ended September 30, 2013 and 2012:
	Three Months Ended September 30, 2013											Three Months Ended September 30, 2012
	Level 1			Level 2				Level 3				Level 1			Level 2				Level 3
	(In millions)
Transfers into Level 1 from	$ N/A			$	—			$	—			$ N/A			$	—			$	—
Transfers into Level 2 from	—			N/A				1				—			N/A				—
Transfers into Level 3 from	—			—				N/A				—			—				N/A
	Nine Months Ended September 30, 2013											Nine Months Ended September 30, 2012
	Level 1			Level 2				Level 3				Level 1			Level 2				Level 3
	(In millions)
Transfers into Level 1 from	$ N/A			$	—			$	—			$ N/A			$	—			$	—
Transfers into Level 2 from	—			N/A				2				—			N/A				2
Transfers into Level 3 from	—			—				N/A				—			29				N/A
The following table presents the unobservable inputs related to Level 3 assets and liabilities as of September 30, 2013:
		30-Sep-13
Commodity Contracts		Derivative Assets				Derivative Liabilities				Valuation Techniques		Unobservable Input		Range								Weighted Average
		(In millions)
Natural Gas		$	34			$	(48	)		Discounted Cash Flow		Forward basis price (per MMBtu)		$	(1.10	)	—	$	4.22	/MMBtu		$	0.1	/MMBtu
Electricity		$	88			$	(83	)		Discounted Cash Flow		Forward basis price (per MWh)		$	(8	)	—	$	15	/MWh		$	2	/MWh
The following table presents the unobservable inputs related to Level 3 assets and liabilities as of December 31, 2012:
		31-Dec-12
Commodity Contracts		Derivative Assets				Derivative Liabilities				Valuation Techniques		Unobservable Input		Range								Weighted Average
		(In millions)
Natural Gas		$	24			$	(62	)		Discounted Cash Flow		Forward basis price (per MMBtu)		$	(0.63	)	—	$	1.95	/MMBtu		$	0.03	/MMBtu
Electricity		$	134			$	(111	)		Discounted Cash Flow		Forward basis price (per MWh)		$	(2	)	—	$	16	/MWh		$	3	/MWh
The unobservable inputs used in the fair value measurement of the electricity and natural gas commodity types consist of inputs that are less observable due in part to lack of available broker quotes, supported by little, if any, market activity at the measurement date or are based on internally developed models. Certain basis prices (i.e. the difference in pricing between two locations) included in the valuation of natural gas and electricity contracts were deemed unobservable.
The inputs listed above would have a direct impact on the fair values of the above security types if they were adjusted. A significant increase (decrease) in the basis price would result in a higher (lower) fair value for long positions, with offsetting impacts to short positions.
Fair Value of Financial Instruments
The fair value of financial instruments included in the table below is determined by using quoted market prices when available. When quoted prices are not available, pricing services may be used to determine the fair value with reference to observable interest rate indexes. DTE Energy has obtained an understanding of how the fair values are derived. DTE Energy also selectively corroborates the fair value of its transactions by comparison of market-based price sources. Discounted cash flow analyses based upon estimated current borrowing rates are also used to determine fair value when quoted market prices are not available. The fair values of notes receivable, excluding capital leases, are estimated using discounted cash flow techniques that incorporate market interest rates as well as assumptions about the remaining life of the loans and credit risk. Depending on the information available, other valuation techniques may be used that rely on internal assumptions and models. Valuation policies and procedures are determined by DTE Energy's Treasury Department which reports to the Company's Vice President and Treasurer.
The following table presents the carrying amount and fair value of financial instruments as of September 30, 2013 and December 31, 2012:
	30-Sep-13																31-Dec-12
	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	$	37			$	—			$	—			$	37			$	39			$	—			$	—		$	39
Dividends payable	$	116			$	116			$	—			$	—			$	107			$	107			$	—		$	—
Short-term borrowings	$	271			$	—			$	271			$	—			$	240			$	—			$	240		$	—
Long-term debt	$	7,729			$	436			$	7,067			$	738			$	7,813			$	507			$	7,453		$	933
See Note 4 for further fair value information on financial and derivative instruments.
Nuclear Decommissioning Trust Funds
DTE Electric has a legal obligation to decommission its nuclear power plants following the expiration of their operating licenses. This obligation is reflected as an asset retirement obligation on the Consolidated Statements of Financial Position. Rates approved by the MPSC provide for the recovery of decommissioning costs of Fermi 2 and the disposal of low-level radioactive waste. DTE Electric is continuing to fund FERC jurisdictional amounts for decommissioning even though explicit provisions are not included in FERC rates.
The following table summarizes the fair value of the nuclear decommissioning trust fund assets:
	30-Sep-13				December 31, 2012
	(In millions)
Fermi 2	$	1,120			$	1,021
Fermi 1	3				3
Low level radioactive waste	16				13
Total	$	1,139			$	1,037
The costs of securities sold are determined on the basis of specific identification. The following table sets forth the gains and losses and proceeds from the sale of securities by the nuclear decommissioning trust funds:
	Three Months Ended September 30,								Nine Months Ended September 30,
	2013				2012				2013				2012
	(In millions)
Realized gains	$	11			$	7			$	30			$	21
Realized losses	$	(11	)		$	(6	)		$	(25	)		$	(17	)
Proceeds from sales of securities	$	13			$	12			$	40			$	48
Realized gains and losses from the sale of securities for the Fermi 2 and the low-level radioactive waste funds are recorded to the Regulatory asset and Nuclear decommissioning liability. The following table sets forth the fair value and unrealized gains for the nuclear decommissioning trust funds:
	30-Sep-13								31-Dec-12
	Fair				Unrealized				Fair				Unrealized
	Value				Gains				Value				Gains
	(In millions)
Equity securities	$	732			$	195			$	631			$	122
Debt securities	395				17				399				27
Cash and cash equivalents	12				—				7				—
	$	1,139			$	212			$	1,037			$	149
The debt securities at September 30, 2013 and December 31, 2012 had an average maturity of approximately 7 and 6 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. DTE Electric recognized $38 million and $44 million of unrealized losses as Regulatory assets at September 30, 2013 and December 31, 2012, respectively. Since the decommissioning of Fermi 1 is funded by DTE Electric rather than through a regulatory recovery mechanism, there is no corresponding regulatory asset treatment. Therefore, unrealized losses incurred by the Fermi 1 trust are recognized in earnings immediately. There were no unrealized losses recognized in the three and nine months ended September 30, 2013 and September 30, 2012 for Fermi 1.
Other Securities
At September 30, 2013 and December 31, 2012, the securities were comprised primarily of money market and equity securities. During the three and nine months ended September 30, 2013 and September 30, 2012, no amounts of unrealized losses on available-for-sale securities were reclassified out of other comprehensive income and realized into net income for the periods. Gains related to trading securities held at September 30, 2013 and September 30, 2012 were $14 million and $11 million, respectively.

Financial_and_Other_Derivative

Financial and Other Derivative Instruments (Notes)	9 Months Ended
	Sep. 30, 2013
Derivative Instruments and Hedges, Assets [Abstract]
FINANCIAL AND OTHER DERIVATIVE INSTRUMENTS	NOTE 4 — FINANCIAL AND OTHER DERIVATIVE INSTRUMENTS
	The Company recognizes all derivatives at their fair value as Derivative Assets or Liabilities on the Consolidated Statements of Financial Position unless they qualify for certain scope exceptions, including the normal purchases and normal sales exception. Further, derivatives that qualify and are designated for hedge accounting are classified as either hedges of a forecasted transaction or the variability of cash flows to be received or paid related to a recognized asset or liability (cash flow hedge), or as hedges of the fair value of a recognized asset or liability or of an unrecognized firm commitment (fair value hedge). For cash flow hedges, the portion of the derivative gain or loss that is effective in offsetting the change in the value of the underlying exposure is deferred in Accumulated other comprehensive income and later reclassified into earnings when the underlying transaction occurs. Gains or losses from the ineffective portion of cash flow hedges are recognized in earnings immediately. For fair value hedges, changes in fair values for the derivative and hedged item are recognized in earnings each period. For derivatives that do not qualify or are not designated for hedge accounting, changes in fair value are recognized in earnings each period.
	The Company’s primary market risk exposure is associated with commodity prices, credit, and interest rates. The Company has risk management policies to monitor and manage market risks. The Company uses derivative instruments to manage some of the exposure. The Company uses derivative instruments for trading purposes in its Energy Trading segment. Contracts classified as derivative instruments include power, natural gas, oil and certain coal forwards, futures, options and swaps, and foreign currency exchange contracts. Items not classified as derivatives include natural gas inventory, pipeline transportation contracts, renewable energy credits and natural gas storage assets.
	Electric — DTE Electric generates, purchases, distributes and sells electricity. DTE Electric uses forward energy contracts to manage changes in the price of electricity and fuel. Substantially all of these contracts meet the normal purchases and sales exemption and are therefore accounted for under the accrual method. Other derivative contracts are recoverable through the PSCR mechanism when settled. This results in the deferral of unrealized gains and losses as Regulatory assets or liabilities until realized.
	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 2016. Substantially all of these contracts meet the normal purchases and sales exemption and are therefore accounted for under the accrual method. DTE Gas may also sell forward transportation and storage capacity contracts. Forward transportation and storage contracts are generally not derivatives and are therefore accounted for under the accrual method.
	Gas Storage and Pipelines — This segment is primarily engaged in services related to the transportation and storage of natural gas. Primarily fixed-priced contracts are used in the marketing and management of transportation and storage services. Generally these contracts are not derivatives and are therefore accounted for under the accrual method.
	Power and Industrial Projects — This segment manages and operates onsite 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, coal, natural gas physical products and energy financial instruments, and provides energy and asset management services utilizing energy commodity derivative instruments. Forwards, futures, options and swap agreements are used to manage exposure to the risk of market price and volume fluctuations in its operations. These derivatives are accounted for by recording changes in fair value to earnings unless hedge accounting criteria are met.
	Energy Trading — Foreign Currency Exchange Risk — Energy Trading has foreign currency exchange forward contracts to economically hedge fixed Canadian dollar commitments existing under natural gas and power purchase and sale contracts and natural gas transportation contracts. The Company enters into these contracts to mitigate price volatility with respect to fluctuations of the Canadian dollar relative to the U.S. dollar. These derivatives are accounted for by recording changes in fair value to earnings unless hedge accounting criteria are met.
	Corporate and Other — Interest Rate Risk — The Company uses interest rate swaps, treasury locks and other derivatives to hedge the risk associated with interest rate market volatility. In 2004 and 2000, the Company entered into a series of interest rate derivatives to limit its sensitivity to market interest rate risk associated with the issuance of long-term debt. Such instruments were designated as cash flow hedges. The Company subsequently issued long-term debt and terminated these hedges at a cost that is included in Other comprehensive loss. Amounts recorded in Other comprehensive loss will be reclassified to interest expense through 2033. In 2013, the Company estimates reclassifying less than $1 million of losses to earnings.
	Credit Risk — The utility and non-utility businesses are exposed to credit risk if customers or counterparties do not comply with their contractual obligations. The Company maintains credit policies that significantly minimize overall credit risk. These policies include an evaluation of potential customers’ and counterparties’ financial condition, credit rating, collateral requirements or other credit enhancements such as letters of credit or guarantees. The Company generally uses standardized agreements that allow the netting of positive and negative transactions associated with a single counterparty. The Company maintains a provision for credit losses based on factors surrounding the credit risk of its customers, historical trends, and other information. Based on the Company’s credit policies and its September 30, 2013 provision for credit losses, the Company’s exposure to counterparty nonperformance is not expected to have a material adverse effect on the Company’s financial statements.
	Derivative Activities
	The Company manages its mark-to-market (MTM) risk on a portfolio basis based upon the delivery period of its contracts and the individual components of the risks within each contract. Accordingly, it records and manages the energy purchase and sale obligations under its contracts in separate components based on the commodity (e.g. electricity or natural gas), the product (e.g. electricity for delivery during peak or off-peak hours), the delivery location (e.g. by region), the risk profile (e.g. forward or option), and the delivery period (e.g. by month and year). The following describes the categories of activities represented by their operating characteristics and key risks:
	•	Asset Optimization — Represents derivative activity associated with assets owned and contracted by DTE Energy, including forward natural gas purchases and sales, natural gas transportation and storage capacity. Changes in the value of derivatives in this category typically economically offset changes in the value of underlying non-derivative positions, which do not qualify for fair value accounting. The difference in accounting treatment of derivatives in this category and the underlying non-derivative positions can result in significant earnings volatility.
	•	Marketing and Origination — Represents derivative activity transacted by originating substantially hedged positions with wholesale energy marketers, producers, end users, utilities, retail aggregators and alternative energy suppliers.
	•	Fundamentals Based Trading — Represents derivative activity transacted with the intent of taking a view, capturing market price changes, or putting capital at risk. This activity is speculative in nature as opposed to hedging an existing exposure.
	•	Other — Includes derivative activity at DTE Electric related to FTRs. Changes in the value of derivative contracts at DTE Electric are recorded as Derivative Assets or Liabilities, with an offset to Regulatory Assets or Liabilities as the settlement value of these contracts will be included in the PSCR mechanism when realized.
	The following tables present the fair value of derivative instruments as of September 30, 2013 and December 31, 2012:
		30-Sep-13								31-Dec-12
		Derivative				Derivative Liabilities				Derivative				Derivative Liabilities
		Assets								Assets
		(In millions)
	Derivatives designated as hedging instruments:
	Interest rate contracts	$	—			$	—			$	—			$	(1	)
	Derivatives not designated as hedging instruments:
	Commodity Contracts:
	Natural Gas	$	483			$	(471	)		$	645			$	(661	)
	Electricity	298				(287		)		360				(351		)
	Other	62				(57		)		11				(7		)
	Total derivatives not designated as hedging instruments:	$	843			$	(815	)		$	1,016			$	(1,019	)
	Total derivatives:
	Current	$	711			$	(668	)		$	862			$	(879	)
	Noncurrent	132				(147		)		154				(141		)
	Total derivatives	$	843			$	(815	)		$	1,016			$	(1,020	)
	Certain of the Company's derivative positions are subject to netting arrangements which provide for offsetting of asset and liability positions as well as related cash collateral. Such netting arrangements generally do not have restrictions. Under such netting arrangements, the Company offsets the fair value of derivative instruments with cash collateral received or paid for those contracts executed with the same counterparty, which reduces the Company's total assets and liabilities. Cash collateral is allocated between the fair value of derivative instruments and customer accounts receivable and payable with the same counterparty on a pro rata basis to the extent there is exposure. Any cash collateral remaining, after the exposure is netted to zero, is reflected in accounts receivable and accounts payable as collateral paid or received, respectively.
	The Company also provides and receives collateral in the form of letters of credit which can be offset against net derivative assets and liabilities as well as accounts receivable and payable. The Company had issued letters of credit of approximately $21 million and $63 million at September 30, 2013 and December 31, 2012, respectively, which could be used to offset our net derivative liabilities. Letters of credit received from third parties which could be used to offset our net derivative assets were not material for the periods presented. Such balances of letters of credit are excluded from the tables below and are not netted with the recognized assets and liabilities in the Consolidated Statements of Financial Position.
	For contracts with certain clearing agents the fair value of derivative instruments is netted against realized positions with the net balance reflected as either 1) a derivative asset or liability or 2) an account receivable or payable. Other than certain clearing agents, accounts receivable and accounts payable that are subject to netting arrangements have not been offset against the fair value of derivative assets and liabilities. Certain contracts that have netting arrangements have not been offset in the Consolidated Statements of Financial Position. The impact of netting these derivative instruments and cash collateral related to such contracts is not material. Only the gross amounts for these derivative instruments are included in the table below.
	As of September 30, 2013, the total cash collateral received, net of cash collateral posted, was $30 million. As of December 31, 2012, the total cash collateral received, net of cash collateral posted, was $20 million. As of September 30, 2013, derivative assets and derivative liabilities are shown net of cash collateral of $29 million and $20 million, respectively. There was no cash collateral related to unrealized positions to net against derivative assets and liabilities as of December 31, 2012. The Company recorded cash collateral paid of $3 million and cash collateral received of $24 million not related to unrealized derivative positions as of September 30, 2013. The Company recorded cash collateral paid of $4 million and cash collateral received of $24 million not related to unrealized derivative positions as of December 31, 2012. These amounts are included in accounts receivable and accounts payable and are recorded net by counterparty.
	The following table presents the netting offsets of derivative assets and liabilities at September 30, 2013 and December 31, 2012:
		30-Sep-13												31-Dec-12
		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	$	483			$	(474	)		$	9			$	645			$	(605	)	$	40
	Electricity	298				(216		)		82				360				(258		)	102
	Other	62				(55		)		7				11				(6		)	5
	Total derivative assets	$	843			$	(745	)		$	98			$	1,016			$	(869	)	$	147
	Derivative liabilities:
	Interest rate contracts	$	—			$	—			$	—			$	(1	)		$	—		$	(1	)
	Commodity Contracts:
	Natural Gas	(471		)		445				(26		)		(661		)		605			(56		)
	Electricity	(287		)		236				(51		)		(351		)		258			(93		)
	Other	(57		)		55				(2		)		(7		)		6			(1		)
	Total derivative liabilities	$	(815	)		$	736			$	(79	)		$	(1,020	)		$	869		$	(151	)
	The following table presents the netting offsets of derivative assets and liabilities at September 30, 2013 and December 31, 2012:
		30-Sep-13																31-Dec-12
		Derivative Assets								Derivative Liabilities								Derivative Assets						Derivative Liabilities
		Current				Noncurrent				Current				Noncurrent				Current			Noncurrent			Current			Noncurrent
		(In millions)
	Reconciliation of derivative instruments to Consolidated Statements of Financial Position:
	Total fair value of derivatives	$	711			$	132			$	(668	)		$	(147	)		$	862		$	154		$	(879	)	$	(141	)
	Counterparty netting	(610		)		(106		)		610				106				(754		)	(115		)	754			115
	Collateral adjustment	(29		)		—				—				20				—			—			—			—
Total derivatives as reported	$	72			$	26			$	(58	)		$	(21	)		$	108		$	39		$	(125	)	$	(26	)
The effect of derivatives not designated as hedging instruments on the Consolidated Statements of Operations for the three and nine months ended September 30, 2013 and 2012 is as follows:
		Location of Gain		Gain (Loss)								Gain (Loss)
		(Loss) Recognized		Recognized in								Recognized in
		in Income on Derivatives		Income on								Income on
				Derivatives for								Derivatives for
				the Three Months Ended September 30,								the Nine Months Ended September 30,
Derivatives not Designated as Hedging Instruments				2013				2012				2013				2012
				(In millions)
Foreign currency exchange contracts		Operating Revenue		$	—			$	(2	)		$	(1	)		$	(1	)
Commodity Contracts:
Natural Gas		Operating Revenue		1				(54		)		37				(51		)
Natural Gas		Fuel, purchased power and gas		(1		)		50				(33		)		45
Electricity		Operating Revenue		22				17				52				52
Other		Operating Revenue		1				1				1				12
Total				$	23			$	12			$	56			$	57
Revenues and energy costs related to trading contracts are presented on a net basis in the Consolidated Statements of Operations. Commodity derivatives used for trading purposes, and financial non-trading commodity derivatives, are accounted for using the mark-to-market 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 mark-to-market method with unrealized and realized gains and losses for sales recorded in Operating revenue and purchases recorded in Fuel, purchased power and gas.
The effects of derivative instruments recoverable through the PSCR mechanism when realized on the Consolidated Statements of Financial Position were $3 million and $7 million in unrealized gains related to FTRs recognized in Regulatory liabilities for the three and nine months ended September 30, 2013, respectively.
The following represents the cumulative gross volume of derivative contracts outstanding as of September 30, 2013:
Commodity		Number of Units
Natural Gas (MMBtu)		683,113,433
Electricity (MWh)		59,672,654
Foreign Currency Exchange ($ CAD)		48,741,288
FTR (MWh)		13,005,024
Various subsidiaries of the Company have entered into contracts which contain ratings triggers and are guaranteed by DTE Energy. These contracts contain provisions which allow the counterparties to request that the Company post cash or letters of credit as collateral in the event that DTE Energy’s credit rating is downgraded below investment grade. Certain of these provisions (known as “hard triggers”) state specific circumstances under which the Company can be asked to post collateral upon the occurrence of a credit downgrade, while other provisions (known as “soft triggers”) are not as specific. For contracts with soft triggers, it is difficult to estimate the amount of collateral which may be requested by counterparties and/or which the Company may ultimately be required to post. The amount of such collateral which could be requested fluctuates based on commodity prices (primarily natural gas, power and coal) and the provisions and maturities of the underlying transactions. As of September 30, 2013, DTE Energy's contractual obligation to post collateral in the form of cash or letter of credit in the event of a downgrade to below investment grade, under both hard trigger and soft trigger provisions, was approximately $327 million.

Discontinued_Operations_Notes

Discontinued Operations (Notes)	9 Months Ended
	Sep. 30, 2013
Discontinued Operations and Disposal Groups [Abstract]
Disposal Groups, Including Discontinued Operations, Disclosure [Text Block]	DISCONTINUED OPERATIONS
	Sale of Unconventional Gas Production Business
	In December 2012, the Company sold its 100% equity interest in its Unconventional Gas Production business which consisted of gas and oil production assets in the western Barnett and Marble Falls shale areas of Texas. The activity of the discontinued business for the three and nine months ended September 30, 2012 is shown below. The amounts exclude general corporate overhead costs, and the related tax effects, and no portion of corporate interest costs were allocated to discontinued operations.
		Three Months Ended		Nine Months Ended
		30-Sep-12		30-Sep-12
		(In millions)
	Operating Revenues	$	16	$	38
	Operation and Maintenance	6		16
	Depreciation, Depletion and Amortization	6		17
	Taxes Other Than Income	1		2
	Operating Income	3		3
	Other (Income) and Deductions	1		4
	Income Tax Expense (Benefit)	1		(1		)
	Net Income Attributable to DTE Energy Company	$	1	$	—

Asset_Retirement_Obligations_N

Asset Retirement Obligations (Notes)	9 Months Ended
	Sep. 30, 2013
Asset Retirement Obligation [Abstract]
Asset Retirement Obligations	ASSET RETIREMENT OBLIGATIONS
	A reconciliation of the asset retirement obligations for the nine months ended September 30, 2013 follows:
		(In millions)
	Asset retirement obligations at December 31, 2012	$	1,719
	Accretion	79
	Liabilities incurred	1
	Liabilities settled	(12		)
	Revision in estimated cash flows	13
	Asset retirement obligations at September 30, 2013	$	1,800

Regulatory_Matters_Notes

Regulatory Matters (Notes)	9 Months Ended
	Sep. 30, 2013
Public Utilities, General Disclosures [Abstract]
Regulatory Matters	REGULATORY MATTERS
	Transition of the City of Detroit's Public Lighting Department's (PLD) Customers to DTE Electric's Distribution System
	Accounting Authority
	On June 28, 2013, DTE Electric filed an application for accounting authority to defer certain costs associated with the transition of the City of Detroit's PLD customers to the DTE Electric distribution system over a five to seven year system conversion period. The Company requested authority to defer as a regulatory asset, all net incremental revenue requirement associated with the transition. The net incremental revenue requirement includes costs to install meters and attach customers; system and customer facility upgrades and repairs; and the difference between DTE Electric's tariff rates and any transitional rates approved in the future. On July 11, 2013, the MPSC approved DTE Electric's request to defer, for accounting purposes, the net incremental revenue requirement.
	The approval excludes the request to defer the difference between DTE Electric's tariff rates and any transitional rates that might be approved by the MPSC in the future. The MPSC will address proposed rates and recovery matters in a future contested proceeding. As the accounting order did not provide a regulatory recovery mechanism, a regulatory asset will not be recognized until a regulatory recovery mechanism is put into place and the recovery of the regulatory asset becomes probable.
	Transitional Reconciliation Mechanism (TRM)
	On July 19, 2013, DTE Electric filed its TRM application proposing a transitional tariff option for certain former PLD customers and a modified line extension provision. The application also proposes a recovery mechanism for the deferred incremental revenue requirement described above. The application further discusses that DTE Electric will be requesting recovery, in subsequent PSCR cases, of PLD transmission delivery service costs incurred while DTE Electric is temporarily relying upon PLD to operate and maintain PLD's system during the system conversion period. If the MPSC determines that the transmission costs are not recoverable in the PSCR, the Company requested recovery as part of the TRM.
	2009 Electric Rate Case Filing - Court of Appeals Remand to MPSC
	In April 2012, the Michigan Court of Appeals (COA) issued a decision relating to an appeal of the January 2010 MPSC rate order in DTE Electric's January 2009 rate case filing. The COA found that the record of evidence in the January 2010 rate order was insufficient to support the MPSC's authorization to recover costs for the advanced metering infrastructure (AMI) program and remanded this matter to the MPSC. On October 17, 2013, the MPSC issued an order affirming the approximately $8 million rate increase authorized in the MPSC's January 2010 rate order for the AMI program and further concluded that the evidence presented after remand supports the authorized cost recovery.
	2010 Electric Rate Case Filing - Court of Appeals Decision
	In July 2013, the COA issued a decision relating to an appeal of the October 2011 MPSC order in DTE Electric's October 2010 rate case filing. The COA found that the record of evidence in the 2010 rate case order was insufficient to support the MPSC's authorization to recover costs for the AMI program and remanded this matter to the MPSC. The MPSC had approved $55 million of the average rate base related to the AMI program in the October 2011 order. DTE Electric is currently operating its AMI program pursuant to the MPSC's approval set forth in the October 2011 order. On August 29, 2013, the MPSC reopened the 2010 electric rate case for the limited purpose of addressing the COA's opinion on AMI. The Company is unable to predict the outcome of this matter or the timing of its resolution.
	Power Supply Cost Recovery Proceedings
	The PSCR process is designed to allow DTE Electric to recover all of its power supply costs if incurred under reasonable and prudent policies and practices. DTE Electric's power supply costs include fuel and related transportation costs, purchased and net interchange power costs, nitrogen oxide and sulfur dioxide emission allowances costs, urea costs, transmission costs and MISO costs. The MPSC reviews these costs, policies and practices for prudence in annual plan and reconciliation filings.
	2012 PSCR Year - In March 2013, DTE Electric filed the 2012 PSCR reconciliation calculating a net under-recovery of approximately $87 million that includes an under-recovery of approximately $148 million for the 2011 PSCR year. The reconciliation includes approximately $30 million of purchased power costs related to the manual shutdown of our Fermi 2 nuclear power plant in June 2012 caused by the failure of one of the plant's two non-safety related feed-water pumps. The plant was restarted on July 30, 2012 which restored production to nominal 68% of full capacity. In September 2013, the repair to the plant was completed and production was returned to full capacity. We were able to purchase sufficient power from MISO to continue to provide uninterrupted service to our customers. Certain intervenors in the reconciliation case have challenged the recovery of some or all of the Fermi-related purchased power costs. Resolution of this matter is expected in 2014.
	Low Income Energy Assistance Fund (LIEAF)
	On July 1, 2013, Michigan Public Act 95 was signed into law and created the LIEAF. The legislation allows the use of a LIEAF funding factor to be determined by the MPSC and assessed on all customer classes of Michigan electric utilities to fund the LIEAF. On July 29, 2013, the MPSC adopted a funding factor of $0.99 per meter per month for all Michigan electric utilities that are participating in the program, including DTE Electric, effective with the September 2013 billing month. The surcharge billed by DTE Electric is remitted to the State of Michigan for subsequent distribution through a grant process to social service agencies and utilities to assist low income customers.
	DTE Gas Uncollectible Expense True-Up Mechanism (UETM)
	In March 2013, DTE Gas filed an application with the MPSC for approval of its UETM reconciliation for 2012 requesting authority to refund approximately $20 million. On September 10, 2013, the MPSC approved a settlement agreement approving the requested 2012 UETM refund over a twelve-month period beginning in October 2013.

Common_Stock

Common Stock	9 Months Ended
	Sep. 30, 2013
Stockholders' Equity Note [Abstract]
Common Stock [Text Block]	COMMON STOCK
	During 2013, the Company contributed the following amounts of DTE Energy Common stock to the DTE Energy Company Affiliates Employee Benefit Plans Master Trust:
	Date	Number of Shares	Price Per Share		Amount
					(In millions)
	12-Mar-13	750,075	$	66.66	$	50
	12-Jun-13	753,579	$	66.35	50
	12-Sep-13	1,522,301	$	65.69	100
					$	200
	The shares for all the contributions were valued at the closing market price of DTE Energy common stock on the contribution dates in accordance with fair value measurement and accounting requirements.

Earnings_Per_Share_Notes

Earnings Per Share (Notes)	9 Months Ended
	Sep. 30, 2013
Earnings Per Share [Abstract]
Earnings per Share	EARNINGS PER SHARE
	The Company reports both basic and diluted earnings per share. The calculation of diluted earnings per share assumes the issuance of potentially dilutive common shares outstanding during the period from the exercise of stock options. A reconciliation of both calculations is presented in the following table for the three months and nine months ended September 30:
		Three Months Ended				Nine Months Ended
		September 30,				September 30,
		2013		2012		2013		2012
		(In millions, except per share amounts)
	Basic Earnings per Share
	Net income attributable to DTE Energy Company	$	198	$	227	$	537	$	529
	Average number of common shares outstanding	175		172		174		171
	Weighted average net restricted shares outstanding	—		1		1		1
	Dividends declared — common shares	$	115	$	106	$	337	$	307
	Dividends declared — net restricted shares	1		1		1		2
	Total distributed earnings	$	116	$	107	$	338	$	309
	Net income less distributed earnings	$	82	$	120	$	199	$	220
	Distributed (dividends per common share)	$	0.66	$	0.62	$	1.93	$	1.8
	Undistributed	0.47		0.7		1.14		1.29
	Total Basic Earnings per Common Share	$	1.13	$	1.32	$	3.07	$	3.09
	Diluted Earnings per Share
	Net income attributable to DTE Energy Company	$	198	$	227	$	537	$	529
	Average number of common shares outstanding	176		172		175		171
	Average incremental shares from assumed exercise of options	—		—		—		—
	Common shares for dilutive calculation	176		172		175		171
	Weighted average net restricted shares outstanding	—		1		1		1
	Dividends declared — common shares	$	115	$	106	$	337	$	307
	Dividends declared — net restricted shares	1		1		1		2
	Total distributed earnings	$	116	$	107	$	338	$	309
	Net income less distributed earnings	$	82	$	120	$	199	$	220
	Distributed (dividends per common share)	$	0.66	$	0.62	$	1.93	$	1.8
	Undistributed	0.47		0.69		1.14		1.28
	Total Diluted Earnings per Common Share	$	1.13	$	1.31	$	3.07	$	3.08

LongTerm_Debt_Notes

Long-Term Debt (Notes)	9 Months Ended
	Sep. 30, 2013
Long-term Debt, Unclassified [Abstract]
Long-term Debt [Text Block]	LONG-TERM DEBT
	Debt Issuances
	In 2013, the following debt was issued:
	Company		Month Issued	Type	Interest Rate		Maturity	Amount
								(In millions)
	DTE Electric		March	Mortgage Bonds (a)	4	%	2043	$	375
	DTE Electric		August	Mortgage Bonds (a)	3.65	%	2024	400
								$	775
	_______________________________________
	(a)	Proceeds were used for the redemption of DTE Electric long-term debt, for the repayment of short-term borrowings, and for general corporate purposes.
	In September 2013, DTE Gas agreed to issue $50 million of 3.64%, 10-year mortgage bonds, $70 million of 3.74%, 12-year mortgage bonds, and $50 million of 3.94%, 15-year mortgage bonds to a group of institutional investors in a private placement transaction. The bonds are expected to close and fund in December 2013. The aggregate proceeds are planned to be used for general corporate purposes.
	Debt Redemptions
	In 2013, the following debt was redeemed:
	Company		Month	Type	Interest Rate		Maturity	Amount
								(In millions)
	DTE Electric		March	Securitization Bonds	6.42	%	2013	$	88
	DTE Electric		March	Tax Exempt Revenue Bonds (a)	5.3	%	2030	51
	DTE Electric		April	Other Long-Term Debt	Various		2013	13
	DTE Gas		April	Senior Notes	5.26	%	2013	60
	DTE Energy		Various	Other Long-Term Debt	Various		2013	4
	DTE Energy		June	Senior Notes	Variable		2013	300
	DTE Electric		September	Securitization Bonds	6.62	%	2015	89
	DTE Electric		September	Senior Notes	6.4	%	2013	250
								$	855
	_______________________________________
	(a)	DTE Electric Tax Exempt Revenue Bonds are issued by a public body that loans the proceeds to DTE Electric on terms substantially mirroring the Revenue Bonds.

ShortTerm_Credit_Arrangements_

Short-Term Credit Arrangements and Borrowings (Notes)	9 Months Ended
	Sep. 30, 2013
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 with a syndicate of 19 banks that can be used for general corporate borrowings, but are intended to provide liquidity support for each of the companies’ commercial paper programs. No one bank provides more than 8.7% of the commitment in any facility. Borrowings under the facilities are available at prevailing short-term interest rates. Additionally, DTE Energy has other facilities to support letter of credit issuance.
	The agreements require the Company to maintain a total funded debt to capitalization ratio of no more than 0.65 to 1. In the agreements, “total funded debt” means all indebtedness of the Company and its 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 the Company and its 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, 2013, the total funded debt to total capitalization ratios for DTE Energy, DTE Electric and DTE Gas are 0.48 to 1, 0.53 to 1 and 0.44 to 1, respectively, and are in compliance with this financial covenant. The availability under the facilities in place at September 30, 2013 is shown in the following table:
		DTE Energy		DTE Electric		DTE Gas		Total
		(In millions)
	Unsecured letter of credit facility, expiring in May 2014	$	50	$	—	$	—	$	50
	Unsecured letter of credit facility, expiring in August 2015	125		—		—		125
	Unsecured revolving credit facility, expiring April 2018	1,200		300		300		1,800
	Total credit facilities at September 30, 2013	1,375		300		300		1,975
	Amounts outstanding at September 30, 2013:
	Commercial paper issuances	44		11		216		271
	Letters of credit	235		—		—		235
		279		11		216		506
	Net availability at September 30, 2013	$	1,096	$	289	$	84	$	1,469
	The Company has other outstanding letters of credit which are not included in the above described facilities totaling approximately $47 million which are used for various corporate purposes.
	In conjunction with maintaining certain exchange traded risk management positions, the Company may be required to post cash collateral with its clearing agent. The Company has a demand financing agreement for up to $100 million with its clearing agent. The agreement, as amended, also allows for up to $50 million of additional margin financing provided that the Company posts a letter of credit for the incremental amount. At September 30, 2013, a $40 million letter of credit was in place, raising the capacity under this facility to $140 million. The $40 million letter of credit is included in the table above. The amount outstanding under this agreement was $75 million and $65 million at September 30, 2013 and December 31, 2012, respectively.

Commitments_and_Contingencies_

Commitments and Contingencies (Notes)	9 Months Ended
	Sep. 30, 2013
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	COMMITMENTS AND CONTINGENCIES
	Environmental
	Electric
	Air - DTE Electric is subject to the EPA ozone and fine particulate transport and acid rain regulations that limit power plant emissions of sulfur dioxide and nitrogen oxides. Since 2005, the EPA and the State of Michigan have issued additional emission reduction regulations relating to ozone, fine particulate, regional haze, mercury, and other air pollution. These rules have led to additional controls on fossil-fueled power plants to reduce nitrogen oxide, sulfur dioxide, mercury and other emissions. To comply with these requirements, DTE Electric spent approximately $1.9 billion through 2012. The Company estimates DTE Electric will make capital expenditures of approximately $190 million in 2013 and up to approximately $1.8 billion of additional capital expenditures through 2021 based on current regulations. Further, 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), finalized in July 2011, required further reductions of sulfur dioxide and nitrogen oxides emissions beginning in 2012. On December 30, 2011, the U.S. Court of Appeals for the District of Columbia (D.C.) Circuit granted the motions to stay the rule, leaving DTE Electric temporarily subject to the previously existing Clean Air Interstate Rule (CAIR). On August 21, 2012, the Court issued its decision, vacating CSAPR and leaving CAIR in place. The EPA's petition seeking a rehearing of the U.S. Court of Appeals' decision regarding the CSAPR was denied on January 24, 2013. On June 24, 2013, the U.S. Supreme Court granted EPA's petition asking the Court to review the D.C. Circuit Court's decision on CSAPR. A ruling by the Supreme Court is not expected before 2014. Notwithstanding the appeal filed with the Supreme Court, the EPA and a number of states have started working on the framework of revised CSAPR regulations which we anticipate to be proposed in the next few years.
	The Mercury and Air Toxics Standard (MATS) rule, formerly known as the Electric Generating Unit Maximum Achievable Control Technology (EGU MACT) Rule was finalized on December 16, 2011. The MATS rule requires reductions of mercury and other hazardous air pollutants beginning in April 2015, with a potential extension to April 2016. DTE Electric has requested and been granted compliance date extensions for some units to April 2016. DTE Electric has tested technologies to determine technological and economic feasibility as MATS compliance alternatives to Flue Gas Desulfurization (FGD) systems. Implementation of Dry Sorbent Injection (DSI) and Activated Carbon Injection (ACI) technologies will allow several units that would not have been economical for FGD installations to continue operation in compliance with MATS.
	In July 2009, DTE Energy received a Notice of Violation/Finding of Violation (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. On August 23, 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. On October 20, 2011, the EPA caused to be filed a Notice of Appeal to the U.S. Court of Appeals for the Sixth Circuit. On March 28, 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. On September 3, 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. The EPA and Sierra Club motions are currently pending with the U. S. District Court Judge.
	DTE Energy and DTE Electric believe that the plants identified by the EPA, including Unit 2 of the Monroe Power Plant, have complied with all applicable federal environmental regulations. Depending upon the outcome of discussions with the EPA regarding the two NOVs/FOVs, DTE Electric could be required to install additional pollution control equipment at some or all of the power plants in question, implement early retirement of facilities where control equipment is not economical, engage in supplemental environmental programs, and/or pay fines. The Company cannot predict the financial impact or outcome of this matter, or the timing of its resolution.
	On March 13, 2013, the Sierra Club filed suit against DTE Energy and DTE Electric alleging violations of the Clean Air Act at four of DTE Electric's coal-fired power plants. The plaintiffs allege 1,499 6-minute periods of excess opacity of air emissions from 2007-2012 at those facilities. The suit asks that the court enjoin DTE Energy and DTE Electric from operating the power plants except in complete compliance with applicable laws and permit requirements, pay civil penalties, conduct beneficial environmental mitigation projects, pay attorney fees and require the installation of any necessary pollution controls or to convert and/or operate the plants' boilers on natural gas to avoid additional violations and to off-set historic unlawful emissions. The resolution of this matter is not expected to have a material effect on the Company's operations or financial statements.
	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. The initial rule published in 2004 was subsequently remanded and a proposed rule published in 2011. The proposed rule specified an eight year compliance timeline. In July 2012, the EPA announced that a notice of its final action on the rule will be issued in June 2013. On June 27, 2013, the EPA announced an agreement to extend the deadline for issuance of the final rule until November 4, 2013. On April 19, 2013, the EPA proposed revised steam electric effluent guidelines regulating wastewater streams from coal-fired power plants including multiple possible options for compliance. The rules are expected to be finalized by May 2014. DTE Electric has provided comments to the EPA. However, it is not possible at this time to quantify the impacts of these developing requirements.
	Contaminated and Other Sites — Prior to the construction of major interstate natural gas pipelines, gas for heating and other uses was manufactured locally from processes involving coal, coke or oil. The facilities, which produced gas, have been designated as manufactured gas plant (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 site. In addition to the MGP sites, the Company is also in the process of cleaning up other contaminated sites, including the area surrounding an ash landfill, electrical distribution substations, electric generating power plants, and underground and aboveground storage tank locations. The findings of these investigations indicated that the estimated cost to remediate these sites is expected to be incurred over the next several years. At September 30, 2013 and December 31, 2012, the Company had $9 million accrued for remediation. Any change in assumptions, such as remediation techniques, nature and extent of contamination and regulatory requirements, could impact the estimate of remedial action costs for the sites and affect the Company’s financial position and cash flows. The Company believes that the likelihood of a materially greater liability than the accrued amount is remote based on current knowledge of the conditions at each site.
	DTE Electric owns and operates a permitted engineered ash storage facility at the Monroe Power Plant to dispose of fly ash from the coal fired power plant. The EPA has published proposed rules to regulate coal ash under the authority of the Resources Conservation and Recovery Act (RCRA). The proposed rule published in June 2010 contains two primary regulatory options to regulate coal ash residue. The EPA is currently considering either designating coal ash as a “Hazardous Waste” as defined by RCRA or regulating coal ash as non-hazardous waste under RCRA. Agencies and legislatures have urged the EPA to regulate coal ash as a non-hazardous waste. If the EPA designates coal ash as a hazardous waste, the agency could apply some, or all, of the disposal and reuse standards that have been applied to other existing hazardous wastes to disposal and reuse of coal ash. Some of the regulatory actions currently being contemplated could have a significant impact on our operations and financial position and the rates we charge our customers. It is not possible to quantify the impact of those expected rulemakings at this time.
	Gas
	Contaminated Sites — Gas segment, owns or previously owned, 15 former MGP sites. Investigations have revealed contamination related to the by-products of gas manufacturing at each site. In addition to the MGP sites, the Company is also in the process of cleaning up other contaminated sites. Cleanup activities associated with these sites will be conducted 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. Accordingly, Gas segment recognizes a liability and corresponding Regulatory asset for estimated investigation and remediation costs at former MGP sites. As of September 30, 2013 and December 31, 2012, the Company had $29 million accrued for remediation. Any change in assumptions, such as remediation techniques, nature and extent of contamination and regulatory requirements, could impact the estimate of remedial action costs for the sites and affect the Company’s financial position and cash flows. The Company anticipates the cost amortization methodology approved by the MPSC for DTE Gas, which allows DTE Gas to amortize the MGP costs over a ten-year period beginning with the year subsequent to the year the MGP costs were incurred and the cost deferral and rate recovery mechanism for Citizens Fuel Gas approved by the City of Adrian, will prevent environmental costs from having a material adverse impact on the Company’s results of operations.
	Non-utility
	The Company’s non-utility businesses are subject to a number of environmental laws and regulations dealing with the protection of the environment from various pollutants.
	The Michigan coke battery facility received and responded to information requests from the EPA that resulted in the issuance of a NOV in June 2007 alleging potential maximum achievable control technologies and new source review violations. The EPA is in the process of reviewing the Company’s position of demonstrated compliance and has not initiated escalated enforcement. At this time, the Company cannot predict the impact of this issue. Furthermore, the Michigan coke battery facility is the subject of an investigation by the MDEQ concerning visible emissions readings that resulted from the Company self reporting to MDEQ questionable activities by an employee of a contractor hired by the Company to perform the visible emissions readings. At this time, the Company cannot predict the impact of this investigation.
	The Company received two NOVs from the Pennsylvania Department of Environmental Protection (PADEP) in 2010 alleging violations of the permit for the Pennsylvania coke battery facility in connection with coal pile storm water runoff. The Company has implemented best management practices to address this issue. The Company recently received a permit to upgrade its existing waste water treatment system and is currently seeking a permit from the PADEP to upgrade its wastewater treatment technology to a biological treatment facility. The Company expects to spend less than $7 million on the existing waste water treatment system to comply with existing water discharge requirements and to upgrade its coal pile storm water runoff management program.
	The Company believes that its non-utility businesses are substantially in compliance with all environmental requirements, other than as noted above.
	Other
	In March 2011, the EPA finalized a new set of regulations regarding the identification of non-hazardous secondary materials that are considered solid waste, industrial boiler and process heater maximum achievable control technologies (IBMACT) for major and area sources, and commercial/industrial solid waste incinerator new source performance standard and emission guidelines (CISWI). The effective dates of the major source IBMACT and CISWI regulations were stayed and a re-proposal was issued by the EPA in December 2011. Final IBMACT and CISWI were issued by the EPA in December 2012. The Company is developing compliance plans to upgrade or convert existing industrial boilers to natural gas and to perform required energy assessments in compliance with the applicable new standards. Capital costs for the boiler conversions and the expenses for the one-time energy assessments are not expected to be material.
	In 2010, the EPA finalized a new 1-hour sulfur dioxide ambient air quality standard that requires states to submit plans for non-attainment areas to be in compliance by 2017. Michigan's non-attainment area includes DTE Energy facilities in southwest Detroit and areas of Wayne County. Preliminary modeling runs by the MDEQ suggest that emission reductions may be required by significant sources of sulfur dioxide emissions in these areas, including DTE Electric power plants and our Michigan coke battery. The state implementation plan process is in the information gathering stage and any required emission reductions for DTE Energy sources to meet the standard cannot be estimated currently.
	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. The Nuclear Electric Insurance Limited (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 $500 million in primary coverage and $2.25 billion of excess coverage for stabilization, decontamination, debris removal, repair and/or replacement of property and decommissioning. The combined coverage limit for total property damage is $2.75 billion, subject to a $1 million deductible. As of April 1, 2013, the total limit for property damage for non-nuclear events is $1.8 billion and an aggregate of $327 million of coverage for extra expenses over a two-year period.
	In 2007, the Terrorism Risk Insurance Extension Act of 2005 (TRIA) was extended through December 31, 2014. A major change in the extension is the inclusion of “domestic” acts of terrorism in the definition of covered or “certified” acts. 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 the NEIL policies, DTE Electric could be liable for maximum assessments of up to approximately $34 million per event if the loss associated with any one event at any insured 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 $127.3 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 U.S. Department of Energy (DOE) for the future storage and disposal of spent nuclear fuel from Fermi 2. DTE Electric is obligated to pay the DOE a fee of 1 mill per kWh of Fermi 2 electricity generated and sold. The fee is 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 currently employs a spent nuclear fuel storage strategy utilizing a fuel pool. The Company continues to develop its on-site dry cask storage facility and anticipates initial offload from the spent fuel pool in 2014. 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.
	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 provided for a payment of approximately $48 million, received in August 2012, for delay-related costs experienced by DTE Electric through 2010, and a claims process for submittal of delay-related costs from 2011 through 2013. DTE Electric has begun the claims process and all claims submitted have been accepted. The settlement proceeds reduced the cost of the dry cask storage facility assets. In February 2013, the U.S. Court of Appeals for the District of Columbia granted a motion to reopen the fee adequacy litigation to review the DOE's latest fee adequacy report which was released in January 2013. DTE Electric will continue to pay fees to the U.S. government's nuclear waste fund pending further action by the D.C. Circuit. The federal government continues to maintain its legal obligation to accept spent nuclear fuel from Fermi 2 for permanent storage. Issues relating to long-term waste disposal policy and to the disposition of funds contributed by DTE Electric ratepayers to the federal waste fund await future governmental action.
	Synthetic Fuel Guarantees
	The Company discontinued the operations of its synthetic fuel production facilities throughout the United States as of December 31, 2007. The Company provided certain guarantees and indemnities in conjunction with the sales of interests in its synfuel facilities. The guarantees cover potential commercial, environmental, oil price and tax-related obligations and will survive until 90 days after expiration of all applicable statutes of limitations. The Company estimates that its maximum potential liability under these guarantees at September 30, 2013 is approximately $1.2 billion. Payment under these guarantees is considered remote.
	Reduced Emissions Fuel Guarantees
	The Company has provided certain guarantees and indemnities in conjunction with the sales of interests in its reduced emissions fuel facilities. The guarantees cover potential commercial, environmental, and tax-related obligations and will survive until 90 days after expiration of all applicable statutes of limitations. The Company estimates that its maximum potential liability under these guarantees at September 30, 2013 is approximately $125 million. Payment under these guarantees is considered remote.
	Other Guarantees
	In certain limited circumstances, the Company enters into contractual guarantees. The Company may guarantee another entity’s obligation in the event it fails to perform. The Company may provide guarantees in certain indemnification agreements. Finally, the Company may provide indirect guarantees for the indebtedness of others. The Company’s guarantees are not individually material with maximum potential payments totaling $60 million at September 30, 2013. Payment under these guarantees is considered remote.
	The Company is periodically required to obtain performance surety bonds in support of obligations to various governmental entities and other companies in connection with its operations. As of September 30, 2013, the Company had approximately $41 million of performance bonds outstanding. In the event that such bonds are called for nonperformance, the Company would be obligated to reimburse the issuer of the performance bond. The Company is released from the performance bonds as the contractual performance is completed and does not believe that a material amount of any currently outstanding performance bonds will be called.
	Labor Contracts
	Our contracts with several bargaining units for the majority of our represented employees were due to expire in June 2013, October 2013 and June 2014. Early negotiations resulted in new contracts that became effective in March 2013. The new contracts will expire in March, June and October 2017.
	Purchase Commitments
	As of September 30, 2013, the Company was party to numerous long-term purchase commitments relating to a variety of goods and services required for the Company’s business. These agreements primarily consist of fuel supply commitments, renewable energy contracts and energy trading contracts. The Company estimates that these commitments will be approximately $6.2 billion from 2013 through 2052.
	The Company also estimates that 2013 capital expenditures will be approximately $2.1 billion. The Company has made certain commitments in connection with expected capital expenditures.
	Bankruptcies
	The Company purchases and sells electricity, natural gas, coal, coke and other energy products from and to governmental entities and numerous companies operating in the steel, automotive, energy, retail, financial and other industries. Certain of its customers have filed for bankruptcy protection under the U.S. Bankruptcy Code. The Company regularly reviews contingent matters relating to these customers and its purchase and sale contracts and records provisions for amounts considered at risk of probable loss. The Company believes its accrued amounts are adequate for probable loss.
	The Company's utilities provide services to the city of Detroit, Michigan (Detroit). Detroit filed for Chapter 9 bankruptcy protection on July 18, 2013. The Company had pre-petition accounts receivable of approximately $20 million outstanding as of the bankruptcy filing date. Detroit has been paying amounts owed in a timely manner and its accounts are substantially current. The Company does not expect Detroit's bankruptcy filing to have a material impact on its financial results.
	Other Contingencies
	The Company is involved in certain other legal, regulatory, administrative and environmental proceedings before various courts, arbitration panels and governmental agencies concerning claims arising in the ordinary course of business. These proceedings include certain contract disputes, additional environmental reviews and investigations, audits, inquiries from various regulators, and pending judicial matters. The Company cannot predict the final disposition of such proceedings. The Company regularly reviews legal matters and records provisions for claims that it can estimate and are considered probable of loss. The resolution of these pending proceedings is not expected to have a material effect on the Company’s operations or financial statements in the periods they are resolved.
	See Notes 4 and 7 for a discussion of contingencies related to derivatives and regulatory matters.

Retirement_Benefits_and_Truste

Retirement Benefits and Trusteed Assets (Notes)	9 Months Ended
	Sep. 30, 2013
Defined Benefit Pension Plans and Defined Benefit Postretirement Plans Disclosure [Abstract]
Pension and Other Postretirement Benefits Disclosure [Text Block]	RETIREMENT BENEFITS AND TRUSTEED ASSETS
	The following table details the components of net periodic benefit costs for pension benefits and other postretirement benefits:
		Pension Benefits						Other Postretirement Benefits
		2013			2012			2013			2012
	Three Months Ended September 30	(In millions)
	Service cost	$	22		$	20		$	9		$	15
	Interest cost	49			51			21			29
	Expected return on plan assets	(67		)	(61		)	(28		)	(23		)
	Amortization of:
	Net actuarial loss	55			48			16			21
	Prior service credit	—			—			(36		)	(6		)
	Net periodic benefit cost (credit)	$	59		$	58		$	(18	)	$	36
		Pension Benefits						Other Postretirement Benefits
		2013			2012			2013			2012
	Nine Months Ended September 30	(In millions)
	Service cost	$	71		$	61		$	37		$	51
	Interest cost	144			153			66			90
	Expected return on plan assets	(200		)	(183		)	(82		)	(69		)
	Amortization of:
	Net actuarial loss	156			133			48			60
	Prior service credit	—			—			(95		)	(20		)
	Net transition liability	—			—			—			1
	Settlements	—			2			—			—
	Net periodic benefit cost (credit)	$	171		$	166		$	(26	)	$	113
	Pension and Other Postretirement Contributions
	During the first nine months of 2013, the Company contributed $250 million to its pension plans, including contributions of DTE Energy common stock of $200 million. See Note 8. At the discretion of management, and depending upon financial market conditions, the Company may make up to an additional $25 million contribution to its pension plans in 2013.
	In January 2013, the Company contributed $145 million to its other postretirement benefit plans. At the discretion of management, the Company may make up to an additional $120 million contribution to its other postretirement benefit plans in 2013.
	Re-Measurement of Other Postretirement Benefit Obligation
	In March 2013, the Company reached agreements on new four-year labor contracts with certain represented employees under several bargaining units. As a term of the agreements, the Company replaced sponsored retiree medical, prescription drug and dental coverage for future Medicare eligible retirees with a Retiree Health Care Allowance (RHCA) account of $3,250 per year. The modification in retiree health coverage will reduce future postretirement benefit costs.
	Based on the impact of such benefit cost savings on the financial statements, the Company re-measured its retiree health plan as of March 31, 2013. In performing the re-measurement, the Company updated its significant actuarial assumptions, including an adjustment to the discount rate from 4.15% at December 31, 2012 to 4.30% at March 31, 2013. Plan assets were also updated to reflect fair value as of the re-measurement date. As a result of the re-measurement, the accumulated postretirement benefit obligation (APBO) was reduced by $258 million. The Company's Accrued postretirement benefit liability at March 31, 2013 was $721 million as compared to $1.2 billion at December 31, 2012, a reduction of $439 million. The reduction reflects the impact of the re-measurement of the plan, January 2013 plan contributions and recognition of first quarter 2013 postretirement benefit costs and benefit payments.
	Beginning April 2013, net postretirement benefit costs were recorded based on the updated actuarial assumptions and benefit changes resulting from the new labor contracts. As a result of the re-measurement, fiscal year 2013 postretirement benefit costs are expected to decrease by approximately $69 million to an annual net benefit of approximately $40 million.

StockBased_Compensation_Notes

Stock-Based Compensation (Notes)	9 Months Ended
	Sep. 30, 2013
Share-based Compensation [Abstract]
Stock-based Compensation	STOCK-BASED COMPENSATION
	The following table summarizes the components of stock-based compensation:
		Three Months Ended						Nine Months Ended
		September 30,						September 30,
		2013			2012			2013		2012
		(In millions)
	Stock-based compensation expense	$	18		$	21		$	81	$	61
	Tax benefit	$	7		$	8		$	31	$	23
	Stock-based compensation cost capitalized in property, plant and equipment	$	1		$	1		$	5	$	3
	Stock Options
	The following table summarizes our stock option activity for the nine months ended September 30, 2013:
		Number of		Weighted			Aggregate
		Options		Average			Intrinsic
				Exercise Price			Value (In millions)
	Options outstanding at December 31, 2012	1,192,670		$	41.86
	Exercised	(399,139	)	$	40.54
	Forfeited or expired	(10,370	)	$	41.46
	Options outstanding at September 30, 2013	783,161		$	42.54		$	20
	Options exercisable at September 30, 2013	783,161		$	42.54		$	20
	As of September 30, 2013, the weighted average remaining contractual life for the exercisable shares is 4.17 years. During the nine months ended September 30, 2013, 200,844 options vested. As of September 30, 2013, all options were vested.
	The intrinsic value of options exercised for the nine months ended September 30, 2013 and 2012 was $11 million and $21 million, respectively. No option expense was recognized for the nine months ended September 30, 2013 and $0.5 million of option expense was recognized for the nine months ended September 30, 2012.
	The Company includes both historical and implied share-price volatility in option volatility. Implied volatility is derived from exchange traded options on DTE Energy common stock. The Company’s expected option life estimate is based on historical data.
	Restricted Stock Awards
	The following table summarizes the Company’s restricted stock awards activity for the nine months ended September 30, 2013:
		Restricted		Weighted Average
		Stock		Grant Date
				Fair Value
	Balance at December 31, 2012	597,648		$	48.33
	Grants	127,785		$	64.72
	Forfeitures	(5,621	)	$	53.53
	Vested and issued	(218,600	)	$	45.39
	Balance at September 30, 2013	501,212		$	53.71
	Performance Share Awards
	The following table summarizes the Company’s performance share activity for the nine months ended September 30, 2013:
		Performance Shares
	Balance at December 31, 2012	1,634,364
	Grants	549,360
	Forfeitures	(36,168	)
	Payouts	(548,624	)
	Balance at September 30, 2013	1,598,932
	Unrecognized Compensation Costs
	As of September 30, 2013, there was $72 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 1.18 years.

Segment_Information_Notes

Segment Information (Notes)	9 Months Ended
	Sep. 30, 2013
Segment Reporting [Abstract]
Segment Information	SEGMENT AND RELATED INFORMATION
	The Company sets strategic goals, allocates resources and evaluates performance based on the following structure:
	Electric segment consists principally of DTE Electric, which is engaged in the generation, purchase, distribution and sale of electricity to approximately 2.1 million residential, commercial and industrial customers in southeastern Michigan.
	Gas segment consists of DTE Gas and Citizens.  DTE Gas 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. Citizens distributes natural gas in Adrian, Michigan to approximately 17,000 customers.
	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 reduced emissions fuel (REF) and sell electricity from biomass-fired energy projects.
	Energy Trading consists of energy marketing and trading operations.
	Corporate and Other, includes various holding company activities, holds certain non-utility debt and energy-related investments.
	The federal income tax provisions or benefits of DTE Energy’s subsidiaries are determined on an individual company basis and recognize the tax benefit of production tax credits and net operating losses if applicable. The state and local income tax provisions of the utility subsidiaries is determined on an individual company basis and recognizes 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						Nine Months Ended
		September 30,						September 30,
		2013			2012			2013			2012
		(In millions)
	Inter-segment Revenues
	Electric	$	6		$	7		$	19		$	22
	Gas	2			1			4			3
	Gas Storage and Pipelines	(2		)	1			2			5
	Power and Industrial Projects	231			225			621			608
	Energy Trading	13			10			36			34
	Corporate and Other	(8		)	(11		)	(23		)	(28		)
	Discontinued Operations	—			1			—			1
		$	242		$	234		$	659		$	645
	Financial data of the business segments follows:
		Three Months Ended						Nine Months Ended
		September 30,						September 30,
		2013			2012			2013			2012
		(In millions)
	Operating Revenues
	Electric	$	1,458		$	1,543		$	3,942		$	4,031
	Gas	161			160			1,013			883
	Gas Storage and Pipelines	34			21			92			73
	Power and Industrial Projects	512			477			1,431			1,375
	Energy Trading	463			223			1,307			723
	Corporate & Other	1			—			2			2
	Reconciliation & Eliminations	(242		)	(234		)	(659		)	(645		)
	Total	$	2,387		$	2,190		$	7,128		$	6,442
	Net Income (Loss) Attributable to DTE Energy by Segment:
	Electric	$	179		$	194		$	383		$	417
	Gas	(13		)	4			91			60
	Gas Storage and Pipelines	16			14			49			48
	Power and Industrial Projects	27			22			46			40
	Energy Trading	(6		)	1			(1		)	3
	Corporate & Other	(5		)	(9		)	(31		)	(39		)
	Discontinued operations	—			1			—			—
	Net Income Attributable to DTE Energy	$	198		$	227		$	537		$	529

Significant_Accounting_Policie1

Significant Accounting Policies (Policies)	9 Months Ended
	Sep. 30, 2013
Accounting Policies [Abstract]
Comprehensive Income [Policy Text Block]	Comprehensive Income
	Comprehensive income is the change in common shareholders’ equity during a period from transactions and events from non-owner sources, including net income. As shown in the following tables, amounts recorded to accumulated other comprehensive loss for the three and nine months ended September 30, 2013 include unrealized gains and losses from derivatives accounted for as cash flow hedges, unrealized gains and losses on available-for-sale securities and the Company’s interest in other comprehensive income of equity investees, which comprise the net unrealized gains and losses on investments, changes in benefit obligations, consisting of deferred actuarial losses, prior service costs and transition amounts related to pension and other postretirement benefit plans, and foreign currency translation adjustments.
Intangible Assets [Policy Text Block]	Emission allowances and renewable energy credits are charged to expense, using average cost, as the allowances and credits are consumed in the operation of the business. The Company amortizes contract intangible assets on a straight-line basis over the expected period of benefit
Income Tax [Policy Text Block]	Income Taxes
	The Company's effective tax rate from continuing operations for the three months ended September 30, 2013 was 28 percent as compared to 32 percent for the three months ended September 30, 2012. The Company's effective tax rate from continuing operations for the nine months ended September 30, 2013 was 29 percent as compared to 32 percent for the nine months ended September 30, 2012. The decrease in the effective tax rate in 2013 is due primarily to higher production tax credits.
	The Company had $3 million of unrecognized tax benefits at September 30, 2013, that, if recognized, would favorably impact its effective tax rate. The Company believes that it is possible that there will be a decrease in the unrecognized tax benefits of up to $1 million in the next twelve months.

Organization_and_Basis_of_Pres1

Organization and Basis of Presentation (Tables)	9 Months Ended
	Sep. 30, 2013
Variable Interest Entity, Consolidated, Carrying Amount, Assets and Liabilities, Net [Abstract]
Schedule of Variable Interest Entities [Table Text Block]
		30-Sep-13						31-Dec-12
		Securitization		Other		Total		Securitization		Other		Total
		(In millions)
	ASSETS
	Cash and cash equivalents	$	—	$	10	$	10	$	—	$	10	$	10
	Restricted cash	44		7		51		102		7		109
	Accounts receivable	39		17		56		34		7		41
	Inventories	—		112		112		—		141		141
	Other current assets	—		1		1		—		1		1
	Property, plant and equipment	—		100		100		—		93		93
	Securitized regulatory assets	280		—		280		413		—		413
	Other assets	5		9		14		7		11		18
		$	368	$	256	$	624	$	556	$	270	$	826
	LIABILITIES
	Accounts payable and accrued current liabilities	$	2	$	35	$	37	$	11	$	14	$	25
	Current portion long-term debt, including capital leases	196		9		205		177		8		185
	Current regulatory liabilities	48		—		48		50		—		50
	Other current liabilities	—		3		3		—		4		4
	Mortgage bonds, notes and other	—		22		22		—		25		25
	Securitization bonds	105		—		105		302		—		302
	Capital lease obligations	—		7		7		—		11		11
	Other long-term liabilities	8		3		11		7		2		9
		$	359	$	79	$	438	$	547	$	64	$	611
Summary of Amounts for Non-Consolidated Variable Interest Entities [Table Text Block]	Amounts for non-consolidated VIEs as of September 30, 2013 and December 31, 2012 are as follows:
		30-Sep-13		December 31, 2012
		(In millions)
	Other investments	$	138	$	130
	Notes receivable	$	3	$	6

Significant_Accounting_Policie2

Significant Accounting Policies (Tables)	9 Months Ended
	Sep. 30, 2013
Accounting Policies [Abstract]
Schedule of Accumulated Other Comprehensive Income (Loss) [Table Text Block]
		Changes in Accumulated Other Comprehensive Loss by Component (a)
		For The Three Months Ended September 30, 2013
		Net Unrealized Gain/(Loss) on Derivatives			Net Unrealized Gain/(Loss) on Investments			Benefit Obligations (b)			Foreign Currency Translation			Total
		(In millions)
	Beginning balance, June 30, 2013	$	(4	)	$	(8	)	$	(143	)	$	—		$	(155	)
	Other comprehensive income before reclassifications	—			1			—			1			2
	Amounts reclassified from accumulated other comprehensive income	—			—			2			—			2
	Net current-period other comprehensive income	—			1			2			1			4
	Ending balance, September 30, 2013	$	(4	)	$	(7	)	$	(141	)	$	1		$	(151	)
		Changes in Accumulated Other Comprehensive Loss by Component (a)
		For The Nine Months Ended September 30, 2013
		Net Unrealized Gain/(Loss) on Derivatives			Net Unrealized Gain/(Loss) on Investments			Benefit Obligations (b)			Foreign Currency Translation			Total
		(In millions)
	Beginning balance, December 31, 2012	$	(4	)	$	(8	)	$	(148	)	$	2		$	(158	)
	Other comprehensive income before reclassifications	—			1			—			(1		)	—
	Amounts reclassified from accumulated other comprehensive income	—			—			7			—			7
	Net current-period other comprehensive income (loss)	—			1			7			(1		)	7
	Ending balance, September 30, 2013	$	(4	)	$	(7	)	$	(141	)	$	1		$	(151	)
	______________________________________
	(a)	All amounts are net of tax.
	(b)	The amounts reclassified from accumulated other comprehensive income are included in the computation of the net periodic pension cost (see Retirement Benefits and Trusteed Assets Note 13).
Schedule of Finite-Lived Intangible Assets by Major Class [Table Text Block]	The Company has certain intangible assets relating to emission allowances, renewable energy credits and non-utility contracts as shown below:
		September 30,			December 31,
		2013			2012
		(In millions)
	Emission allowances	$	3		$	6
	Renewable energy credits	48			44
	Contract intangible assets	126			139
		177			189
	Less accumulated amortization	41			34
	Intangible assets, net	136			155
	Less current intangible assets	14			20
		$	122		$	135

Fair_Value_Tables

Fair Value (Tables)	9 Months Ended
	Sep. 30, 2013
Fair Value Disclosures [Abstract]
Assets and liabilities measured and recorded at fair value on a recurring basis	The following table presents assets and liabilities measured and recorded at fair value on a recurring basis as of September 30, 2013 and December 31, 2012:
		30-Sep-13																				31-Dec-12
		Level 1				Level 2				Level 3				Netting (a)				Net Balance				Level 1				Level 2			Level 3			Netting (a)			Net Balance
		(In millions)
	Assets:
	Cash equivalents (b)	$	—			$	68			$	—			$	—			$	68			$	—			$	123		$	—		$	—		$	123
	Nuclear decommissioning trusts	757				382				—				—				1,139				694				343			—			—			1,037
	Other investments (c) (d)	76				48				—				—				124				66				44			—			—			110
	Derivative assets:
	Commodity Contracts:
	Natural Gas	388				61				34				(474		)		9				555				66			24			(605		)	40
	Electricity	—				210				88				(216		)		82				—				226			134			(258		)	102
	Other	48				9				5				(55		)		7				6				3			2			(6		)	5
	Total derivative assets	436				280				127				(745		)		98				561				295			160			(869		)	147
	Total	$	1,269			$	778			$	127			$	(745	)		$	1,429			$	1,321			$	805		$	160		$	(869	)	$	1,417
	Liabilities:
	Derivative liabilities:
	Interest rate contracts	$	—			$	—			$	—			$	—			$	—			$	—			$	(1	)	$	—		$	—		$	(1	)
	Commodity Contracts:
	Natural Gas	(374		)		(49		)		(48		)		445				(26		)		(526		)		(73		)	(62		)	605			(56		)
	Electricity	—				(204		)		(83		)		236				(51		)		—				(240		)	(111		)	258			(93		)
	Other	(52		)		(5		)		—				55				(2		)		(6		)		(1		)	—			6			(1		)
	Total derivative liabilities	(426		)		(258		)		(131		)		736				(79		)		(532		)		(315		)	(173		)	869			(151		)
	Total	$	(426	)		$	(258	)		$	(131	)		$	736			$	(79	)		$	(532	)		$	(315	)	$	(173	)	$	869		$	(151	)
	Net Assets (Liabilities) at the end of the period	$	843			$	520			$	(4	)		$	(9	)		$	1,350			$	789			$	490		$	(13	)	$	—		$	1,266
	Assets:
	Current	$	400			$	285			$	94			$	(639	)		$	140			$	493			$	372		$	120		$	(754	)	$	231
	Noncurrent (e)	869				493				33				(106		)		1,289				828				433			40			(115		)	1,186
	Total Assets	$	1,269			$	778			$	127			$	(745	)		$	1,429			$	1,321			$	805		$	160		$	(869	)	$	1,417
	Liabilities:
	Current	$	(379	)		$	(189	)		$	(100	)		$	610			$	(58	)		$	(466	)		$	(269	)	$	(144	)	$	754		$	(125	)
	Noncurrent	(47		)		(69		)		(31		)		126				(21		)		(66		)		(46		)	(29		)	115			(26		)
	Total Liabilities	$	(426	)		$	(258	)		$	(131	)		$	736			$	(79	)		$	(532	)		$	(315	)	$	(173	)	$	869		$	(151	)
	Net Assets (Liabilities) at the end of the period	$	843			$	520			$	(4	)		$	(9	)		$	1,350			$	789			$	490		$	(13	)	$	—		$	1,266
	_______________________________________
	(a)	Amounts represent the impact of master netting agreements that allow the Company to net gain and loss positions and cash collateral held or placed with the same counterparties.
	(b)	At September 30, 2013, available-for-sale securities of $68 million included $51 million and $17 million of cash equivalents included in Restricted cash and Other investments, respectively, on the Consolidated Statements of Financial Position. At December 31, 2012, available-for-sale securities of $123 million, included $109 million and $14 million of cash equivalents included in Restricted cash and Other investments, respectively, on the Consolidated Statements of Financial Position.
	(c)	Excludes cash surrender value of life insurance investments.
	(d)	Available-for-sale equity securities of $6 million at September 30, 2013 and $5 million at December 31, 2012, are included in Other investments on the Consolidated Statements of Financial Position.
	(e)	Includes $124 million and $110 million at September 30, 2013 and December 31, 2012, respectively, of Other investments that are included in the Consolidated Statements of Financial Position in Other investments.
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Table Text Block]	The following tables present the fair value reconciliation of Level 3 assets and liabilities measured at fair value on a recurring basis for the three months and nine months ended September 30, 2013 and 2012:
		Three Months Ended September 30, 2013																Three Months Ended September 30, 2012
		Natural Gas				Electricity				Other				Total				Natural Gas				Electricity				Other			Total
		(In millions)
	Net Assets (Liabilities) as of June 30	$	(30	)		$	12			$	2			$	(16	)		$	2			$	50			$	5		$	57
	Transfers into Level 3	—				—				—				—				—				—				—			—
	Transfers out of Level 3	—				(1		)		—				(1		)		—				—				—			—
	Total gains (losses):
	Included in earnings	8				17				—				25				(43		)		12				1			(30		)
	Recorded in regulatory assets/liabilities	—				—				3				3				—				—				7			7
	Purchases, issuances and settlements:
	Settlements	8				(23		)		—				(15		)		(3		)		(38		)		(7		)	(48		)
	Net Assets (Liabilities) as of September 30	$	(14	)		$	5			$	5			$	(4	)		$	(44	)		$	24			$	6		$	(14	)
	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, 2013 and 2012 and reflected in Operating revenues and Fuel, purchased power and gas in the Consolidated Statements of Operations	$	(8	)		$	8			$	—			$	—			$	(43	)		$	5			$	1		$	(37	)
		Nine Months Ended September 30, 2013																Nine Months Ended September 30, 2012
		Natural Gas				Electricity				Other				Total				Natural Gas				Electricity				Other			Total
		(In millions)
	Net Assets (Liabilities) as of December 31	$	(38	)		$	23			$	2			$	(13	)		$	6			$	32			$	6		$	44
	Transfers into Level 3	—				—				—				—				1				28				—			29
	Transfers out of Level 3	(2		)		—				—				(2		)		(2		)		—				—			(2		)
	Total gains (losses):
	Included in earnings	(1		)		44				—				43				(38		)		53				—			15
	Recorded in regulatory assets/liabilities	—				—				7				7				—				—				12			12
	Purchases, issuances and settlements:
	Purchases	—				(1		)		—				(1		)		—				1				—			1
	Settlements	27				(61		)		(4		)		(38		)		(11		)		(90		)		(12		)	(113		)
	Net Assets (Liabilities) as of September 30	$	(14	)		$	5			$	5			$	(4	)		$	(44	)		$	24			$	6		$	(14	)
	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, 2013 and 2012 and reflected in Operating revenues and Fuel, purchased power and gas in the Consolidated Statements of Operations	$	(14	)		$	36			$	—			$	22			$	(39	)		$	43			$	—		$	4
Transfers Between Level 1 Level 2 and Level 3 [Table Text Block]	The following table shows transfers between the levels of the fair value hierarchy for the three months and nine months ended September 30, 2013 and 2012:
		Three Months Ended September 30, 2013											Three Months Ended September 30, 2012
		Level 1			Level 2				Level 3				Level 1			Level 2				Level 3
		(In millions)
	Transfers into Level 1 from	$ N/A			$	—			$	—			$ N/A			$	—			$	—
	Transfers into Level 2 from	—			N/A				1				—			N/A				—
	Transfers into Level 3 from	—			—				N/A				—			—				N/A
		Nine Months Ended September 30, 2013											Nine Months Ended September 30, 2012
		Level 1			Level 2				Level 3				Level 1			Level 2				Level 3
		(In millions)
	Transfers into Level 1 from	$ N/A			$	—			$	—			$ N/A			$	—			$	—
	Transfers into Level 2 from	—			N/A				2				—			N/A				2
	Transfers into Level 3 from	—			—				N/A				—			29				N/A
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Table Text Block]	The following table presents the unobservable inputs related to Level 3 assets and liabilities as of September 30, 2013:
			30-Sep-13
	Commodity Contracts		Derivative Assets				Derivative Liabilities				Valuation Techniques		Unobservable Input		Range								Weighted Average
			(In millions)
	Natural Gas		$	34			$	(48	)		Discounted Cash Flow		Forward basis price (per MMBtu)		$	(1.10	)	—	$	4.22	/MMBtu		$	0.1	/MMBtu
	Electricity		$	88			$	(83	)		Discounted Cash Flow		Forward basis price (per MWh)		$	(8	)	—	$	15	/MWh		$	2	/MWh
	The following table presents the unobservable inputs related to Level 3 assets and liabilities as of December 31, 2012:
			31-Dec-12
	Commodity Contracts		Derivative Assets				Derivative Liabilities				Valuation Techniques		Unobservable Input		Range								Weighted Average
			(In millions)
	Natural Gas		$	24			$	(62	)		Discounted Cash Flow		Forward basis price (per MMBtu)		$	(0.63	)	—	$	1.95	/MMBtu		$	0.03	/MMBtu
	Electricity		$	134			$	(111	)		Discounted Cash Flow		Forward basis price (per MWh)		$	(2	)	—	$	16	/MWh		$	3	/MWh
Fair Value of Financial Instruments [Table Text Block]	The following table presents the carrying amount and fair value of financial instruments as of September 30, 2013 and December 31, 2012:
		30-Sep-13																31-Dec-12
		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	$	37			$	—			$	—			$	37			$	39			$	—			$	—		$	39
	Dividends payable	$	116			$	116			$	—			$	—			$	107			$	107			$	—		$	—
	Short-term borrowings	$	271			$	—			$	271			$	—			$	240			$	—			$	240		$	—
	Long-term debt	$	7,729			$	436			$	7,067			$	738			$	7,813			$	507			$	7,453		$	933
Fair Value of Nuclear Decommissioning Trust Fund Assets [Table Text Block]	The following table summarizes the fair value of the nuclear decommissioning trust fund assets:
		30-Sep-13				December 31, 2012
		(In millions)
	Fermi 2	$	1,120			$	1,021
	Fermi 1	3				3
	Low level radioactive waste	16				13
	Total	$	1,139			$	1,037
Schedule of Realized Gain (Loss) [Table Text Block]	The following table sets forth the 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,
		2013				2012				2013				2012
		(In millions)
	Realized gains	$	11			$	7			$	30			$	21
	Realized losses	$	(11	)		$	(6	)		$	(25	)		$	(17	)
	Proceeds from sales of securities	$	13			$	12			$	40			$	48
Fair Value and Unrealized Gains for Nuclear Decommissioning Trust Fund [Table Text Block]	The following table sets forth the fair value and unrealized gains for the nuclear decommissioning trust funds:
		30-Sep-13								31-Dec-12
		Fair				Unrealized				Fair				Unrealized
		Value				Gains				Value				Gains
		(In millions)
	Equity securities	$	732			$	195			$	631			$	122
	Debt securities	395				17				399				27
	Cash and cash equivalents	12				—				7				—
		$	1,139			$	212			$	1,037			$	149

Financial_and_Other_Derivative1

Financial and Other Derivative Instruments (Tables)	9 Months Ended
	Sep. 30, 2013
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Fair value of derivative instruments	The following tables present the fair value of derivative instruments as of September 30, 2013 and December 31, 2012:
		30-Sep-13								31-Dec-12
		Derivative				Derivative Liabilities				Derivative				Derivative Liabilities
		Assets								Assets
		(In millions)
	Derivatives designated as hedging instruments:
	Interest rate contracts	$	—			$	—			$	—			$	(1	)
	Derivatives not designated as hedging instruments:
	Commodity Contracts:
	Natural Gas	$	483			$	(471	)		$	645			$	(661	)
	Electricity	298				(287		)		360				(351		)
	Other	62				(57		)		11				(7		)
	Total derivatives not designated as hedging instruments:	$	843			$	(815	)		$	1,016			$	(1,019	)
	Total derivatives:
	Current	$	711			$	(668	)		$	862			$	(879	)
	Noncurrent	132				(147		)		154				(141		)
	Total derivatives	$	843			$	(815	)		$	1,016			$	(1,020	)
Netting Offsets of Derivative Assets and Liabilities [Table Text Block]	The following table presents the netting offsets of derivative assets and liabilities at September 30, 2013 and December 31, 2012:
		30-Sep-13												31-Dec-12
		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	$	483			$	(474	)		$	9			$	645			$	(605	)	$	40
	Electricity	298				(216		)		82				360				(258		)	102
	Other	62				(55		)		7				11				(6		)	5
	Total derivative assets	$	843			$	(745	)		$	98			$	1,016			$	(869	)	$	147
	Derivative liabilities:
	Interest rate contracts	$	—			$	—			$	—			$	(1	)		$	—		$	(1	)
	Commodity Contracts:
	Natural Gas	(471		)		445				(26		)		(661		)		605			(56		)
	Electricity	(287		)		236				(51		)		(351		)		258			(93		)
	Other	(57		)		55				(2		)		(7		)		6			(1		)
	Total derivative liabilities	$	(815	)		$	736			$	(79	)		$	(1,020	)		$	869		$	(151	)
Netting Offsets of Derivative Assets and Liabilities Reconciliation to the Statements of Financial Position [Table Text Block]	The following table presents the netting offsets of derivative assets and liabilities at September 30, 2013 and December 31, 2012:
		30-Sep-13																31-Dec-12
		Derivative Assets								Derivative Liabilities								Derivative Assets						Derivative Liabilities
		Current				Noncurrent				Current				Noncurrent				Current			Noncurrent			Current			Noncurrent
		(In millions)
	Reconciliation of derivative instruments to Consolidated Statements of Financial Position:
	Total fair value of derivatives	$	711			$	132			$	(668	)		$	(147	)		$	862		$	154		$	(879	)	$	(141	)
	Counterparty netting	(610		)		(106		)		610				106				(754		)	(115		)	754			115
	Collateral adjustment	(29		)		—				—				20				—			—			—			—
	Total derivatives as reported	$	72			$	26			$	(58	)		$	(21	)		$	108		$	39		$	(125	)	$	(26	)
Gain (Loss) Recognized in Income on Derivative	The effect of derivatives not designated as hedging instruments on the Consolidated Statements of Operations for the three and nine months ended September 30, 2013 and 2012 is as follows:
			Location of Gain		Gain (Loss)								Gain (Loss)
			(Loss) Recognized		Recognized in								Recognized in
			in Income on Derivatives		Income on								Income on
					Derivatives for								Derivatives for
					the Three Months Ended September 30,								the Nine Months Ended September 30,
	Derivatives not Designated as Hedging Instruments				2013				2012				2013				2012
					(In millions)
	Foreign currency exchange contracts		Operating Revenue		$	—			$	(2	)		$	(1	)		$	(1	)
	Commodity Contracts:
	Natural Gas		Operating Revenue		1				(54		)		37				(51		)
	Natural Gas		Fuel, purchased power and gas		(1		)		50				(33		)		45
	Electricity		Operating Revenue		22				17				52				52
	Other		Operating Revenue		1				1				1				12
	Total				$	23			$	12			$	56			$	57
Volume of Commodity Contracts [Table Text Block]	The following represents the cumulative gross volume of derivative contracts outstanding as of September 30, 2013:
	Commodity		Number of Units
	Natural Gas (MMBtu)		683,113,433
	Electricity (MWh)		59,672,654
	Foreign Currency Exchange ($ CAD)		48,741,288
	FTR (MWh)		13,005,024

Discontinued_Operations_Discon

Discontinued Operations Discontinued Operations (Tables)	9 Months Ended
	Sep. 30, 2013
Discontinued Operations and Disposal Groups [Abstract]
Schedule of Disposal Groups, Including Discontinued Operations, Income Statement, Balance Sheet and Additional Disclosures [Table Text Block]
		Three Months Ended		Nine Months Ended
		30-Sep-12		30-Sep-12
		(In millions)
	Operating Revenues	$	16	$	38
	Operation and Maintenance	6		16
	Depreciation, Depletion and Amortization	6		17
	Taxes Other Than Income	1		2
	Operating Income	3		3
	Other (Income) and Deductions	1		4
	Income Tax Expense (Benefit)	1		(1		)
	Net Income Attributable to DTE Energy Company	$	1	$	—

Asset_Retirement_Obligations_T

Asset Retirement Obligations (Tables)	9 Months Ended
	Sep. 30, 2013
Asset Retirement Obligation Disclosure [Abstract]
Schedule of Change in Asset Retirement Obligation [Table Text Block]	A reconciliation of the asset retirement obligations for the nine months ended September 30, 2013 follows:
		(In millions)
	Asset retirement obligations at December 31, 2012	$	1,719
	Accretion	79
	Liabilities incurred	1
	Liabilities settled	(12		)
	Revision in estimated cash flows	13
	Asset retirement obligations at September 30, 2013	$	1,800

Common_Stock_Common_Stock_Tabl

Common Stock Common Stock (Tables)	9 Months Ended
	Sep. 30, 2013
Stockholders' Equity Note [Abstract]
Common Stock Issued [Table Text Block]	During 2013, the Company contributed the following amounts of DTE Energy Common stock to the DTE Energy Company Affiliates Employee Benefit Plans Master Trust:
	Date	Number of Shares	Price Per Share		Amount
					(In millions)
	12-Mar-13	750,075	$	66.66	$	50
	12-Jun-13	753,579	$	66.35	50
	12-Sep-13	1,522,301	$	65.69	100
					$	200

Earnings_Per_Share_Tables

Earnings Per Share (Tables)	9 Months Ended
	Sep. 30, 2013
Earnings Per Share [Abstract]
Schedule of Earnings Per Share, Basic and Diluted [Table Text Block]	A reconciliation of both calculations is presented in the following table for the three months and nine months ended September 30:
		Three Months Ended				Nine Months Ended
		September 30,				September 30,
		2013		2012		2013		2012
		(In millions, except per share amounts)
	Basic Earnings per Share
	Net income attributable to DTE Energy Company	$	198	$	227	$	537	$	529
	Average number of common shares outstanding	175		172		174		171
	Weighted average net restricted shares outstanding	—		1		1		1
	Dividends declared — common shares	$	115	$	106	$	337	$	307
	Dividends declared — net restricted shares	1		1		1		2
	Total distributed earnings	$	116	$	107	$	338	$	309
	Net income less distributed earnings	$	82	$	120	$	199	$	220
	Distributed (dividends per common share)	$	0.66	$	0.62	$	1.93	$	1.8
	Undistributed	0.47		0.7		1.14		1.29
	Total Basic Earnings per Common Share	$	1.13	$	1.32	$	3.07	$	3.09
	Diluted Earnings per Share
	Net income attributable to DTE Energy Company	$	198	$	227	$	537	$	529
	Average number of common shares outstanding	176		172		175		171
	Average incremental shares from assumed exercise of options	—		—		—		—
	Common shares for dilutive calculation	176		172		175		171
	Weighted average net restricted shares outstanding	—		1		1		1
	Dividends declared — common shares	$	115	$	106	$	337	$	307
	Dividends declared — net restricted shares	1		1		1		2
	Total distributed earnings	$	116	$	107	$	338	$	309
	Net income less distributed earnings	$	82	$	120	$	199	$	220
	Distributed (dividends per common share)	$	0.66	$	0.62	$	1.93	$	1.8
	Undistributed	0.47		0.69		1.14		1.28
	Total Diluted Earnings per Common Share	$	1.13	$	1.31	$	3.07	$	3.08

LongTerm_Debt_Tables

Long-Term Debt (Tables)	9 Months Ended
	Sep. 30, 2013
Long-term Debt, Unclassified [Abstract]
Schedule of Issued Debt [Table Text Block]	In 2013, the following debt was issued:
	Company		Month Issued	Type	Interest Rate		Maturity	Amount
								(In millions)
	DTE Electric		March	Mortgage Bonds (a)	4	%	2043	$	375
	DTE Electric		August	Mortgage Bonds (a)	3.65	%	2024	400
								$	775
	_______________________________________
	(a)	Proceeds were used for the redemption of DTE Electric long-term debt, for the repayment of short-term borrowings, and for general corporate purposes.
Schedule of Extinguishment of Debt [Table Text Block]	In 2013, the following debt was redeemed:
	Company		Month	Type	Interest Rate		Maturity	Amount
								(In millions)
	DTE Electric		March	Securitization Bonds	6.42	%	2013	$	88
	DTE Electric		March	Tax Exempt Revenue Bonds (a)	5.3	%	2030	51
	DTE Electric		April	Other Long-Term Debt	Various		2013	13
	DTE Gas		April	Senior Notes	5.26	%	2013	60
	DTE Energy		Various	Other Long-Term Debt	Various		2013	4
	DTE Energy		June	Senior Notes	Variable		2013	300
	DTE Electric		September	Securitization Bonds	6.62	%	2015	89
	DTE Electric		September	Senior Notes	6.4	%	2013	250
								$	855
	_______________________________________
	(a)	DTE Electric Tax Exempt Revenue Bonds are issued by a public body that loans the proceeds to DTE Electric on terms substantially mirroring the Revenue Bonds.

ShortTerm_Credit_Arrangements_1

Short-Term Credit Arrangements and Borrowings (Tables)	9 Months Ended
	Sep. 30, 2013
Short-term Debt [Abstract]
Schedule of Line of Credit Facilities [Table Text Block]	The availability under the facilities in place at September 30, 2013 is shown in the following table:
		DTE Energy		DTE Electric		DTE Gas		Total
		(In millions)
	Unsecured letter of credit facility, expiring in May 2014	$	50	$	—	$	—	$	50
	Unsecured letter of credit facility, expiring in August 2015	125		—		—		125
	Unsecured revolving credit facility, expiring April 2018	1,200		300		300		1,800
	Total credit facilities at September 30, 2013	1,375		300		300		1,975
	Amounts outstanding at September 30, 2013:
	Commercial paper issuances	44		11		216		271
	Letters of credit	235		—		—		235
		279		11		216		506
	Net availability at September 30, 2013	$	1,096	$	289	$	84	$	1,469

Retirement_Benefits_and_Truste1

Retirement Benefits and Trusteed Assets (Tables)	9 Months Ended
	Sep. 30, 2013
Defined Benefit Pension Plans and Defined Benefit Postretirement Plans Disclosure [Abstract]
Schedule of Costs of Retirement Plans [Table Text Block]	The following table details the components of net periodic benefit costs for pension benefits and other postretirement benefits:
		Pension Benefits						Other Postretirement Benefits
		2013			2012			2013			2012
	Three Months Ended September 30	(In millions)
	Service cost	$	22		$	20		$	9		$	15
	Interest cost	49			51			21			29
	Expected return on plan assets	(67		)	(61		)	(28		)	(23		)
	Amortization of:
	Net actuarial loss	55			48			16			21
	Prior service credit	—			—			(36		)	(6		)
	Net periodic benefit cost (credit)	$	59		$	58		$	(18	)	$	36
		Pension Benefits						Other Postretirement Benefits
		2013			2012			2013			2012
	Nine Months Ended September 30	(In millions)
	Service cost	$	71		$	61		$	37		$	51
	Interest cost	144			153			66			90
	Expected return on plan assets	(200		)	(183		)	(82		)	(69		)
	Amortization of:
	Net actuarial loss	156			133			48			60
	Prior service credit	—			—			(95		)	(20		)
	Net transition liability	—			—			—			1
	Settlements	—			2			—			—
	Net periodic benefit cost (credit)	$	171		$	166		$	(26	)	$	113

StockBased_Compensation_Tables

Stock-Based Compensation (Tables)	9 Months Ended
	Sep. 30, 2013
Share-based Compensation [Abstract]
Schedule of Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Table Text Block]	The following table summarizes the components of stock-based compensation:
		Three Months Ended						Nine Months Ended
		September 30,						September 30,
		2013			2012			2013		2012
		(In millions)
	Stock-based compensation expense	$	18		$	21		$	81	$	61
	Tax benefit	$	7		$	8		$	31	$	23
	Stock-based compensation cost capitalized in property, plant and equipment	$	1		$	1		$	5	$	3
Schedule of Share-based Compensation, Stock Options, Activity [Table Text Block]	The following table summarizes our stock option activity for the nine months ended September 30, 2013:
		Number of		Weighted			Aggregate
		Options		Average			Intrinsic
				Exercise Price			Value (In millions)
	Options outstanding at December 31, 2012	1,192,670		$	41.86
	Exercised	(399,139	)	$	40.54
	Forfeited or expired	(10,370	)	$	41.46
	Options outstanding at September 30, 2013	783,161		$	42.54		$	20
	Options exercisable at September 30, 2013	783,161		$	42.54		$	20
Schedule of Share-based Compensation Arrangements by Share-based Payment Award [Table Text Block]	Restricted Stock Awards
	The following table summarizes the Company’s restricted stock awards activity for the nine months ended September 30, 2013:
		Restricted		Weighted Average
		Stock		Grant Date
				Fair Value
	Balance at December 31, 2012	597,648		$	48.33
	Grants	127,785		$	64.72
	Forfeitures	(5,621	)	$	53.53
	Vested and issued	(218,600	)	$	45.39
	Balance at September 30, 2013	501,212		$	53.71
	Performance Share Awards
	The following table summarizes the Company’s performance share activity for the nine months ended September 30, 2013:
		Performance Shares
	Balance at December 31, 2012	1,634,364
	Grants	549,360
	Forfeitures	(36,168	)
	Payouts	(548,624	)
	Balance at September 30, 2013	1,598,932

Segment_Information_Tables

Segment Information (Tables)	9 Months Ended
	Sep. 30, 2013
Segment Reporting [Abstract]
Reconciliation of Revenue from Segments to Consolidated [Table Text Block]	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						Nine Months Ended
		September 30,						September 30,
		2013			2012			2013			2012
		(In millions)
	Inter-segment Revenues
	Electric	$	6		$	7		$	19		$	22
	Gas	2			1			4			3
	Gas Storage and Pipelines	(2		)	1			2			5
	Power and Industrial Projects	231			225			621			608
	Energy Trading	13			10			36			34
	Corporate and Other	(8		)	(11		)	(23		)	(28		)
	Discontinued Operations	—			1			—			1
		$	242		$	234		$	659		$	645
	Financial data of the business segments follows:
		Three Months Ended						Nine Months Ended
		September 30,						September 30,
		2013			2012			2013			2012
		(In millions)
	Operating Revenues
	Electric	$	1,458		$	1,543		$	3,942		$	4,031
	Gas	161			160			1,013			883
	Gas Storage and Pipelines	34			21			92			73
	Power and Industrial Projects	512			477			1,431			1,375
	Energy Trading	463			223			1,307			723
	Corporate & Other	1			—			2			2
	Reconciliation & Eliminations	(242		)	(234		)	(659		)	(645		)
	Total	$	2,387		$	2,190		$	7,128		$	6,442
Reconciliation of Operating Profit (Loss) from Segments to Consolidated [Table Text Block]
	Net Income (Loss) Attributable to DTE Energy by Segment:
	Electric	$	179		$	194		$	383		$	417
	Gas	(13		)	4			91			60
	Gas Storage and Pipelines	16			14			49			48
	Power and Industrial Projects	27			22			46			40
	Energy Trading	(6		)	1			(1		)	3
	Corporate & Other	(5		)	(9		)	(31		)	(39		)
	Discontinued operations	—			1			—			—
	Net Income Attributable to DTE Energy	$	198		$	227		$	537		$	529

Organization_and_Basis_of_Pres2

Organization and Basis of Presentation (Details) (USD $)	Sep. 30, 2013	Dec. 31, 2012	Sep. 30, 2012	Dec. 31, 2011
In Millions, unless otherwise specified
Assets [Abstract]
Cash and cash equivalents	$71	$65	$59	$68
Restricted cash	64	122
Accounts receivable	1,239	1,336
Other current assets	248	194
Property, plant and equipment	15,511	14,684
Securitized regulatory assets	280	413
Other assets	198	197
Total Assets	26,231	26,339
Liabilities [Abstract]
Current portion long-term debt, including, capital leases	896	817
Current regulatory liabilities	230	89
Other current liabilities	457	449
Mortgage bonds, notes and other	6,253	6,220
Securitization bonds	105	302
Capital lease obligations	8	12
Other long term liabilities	290	306
Variable Interest Entity Securitization [Member]
Assets [Abstract]
Cash and cash equivalents	0	0
Restricted cash	44	102
Accounts receivable	39	34
Inventories	0	0
Other current assets	0	0
Property, plant and equipment	0	0
Securitized regulatory assets	280	413
Other assets	5	7
Total Assets	368	556
Liabilities [Abstract]
Accounts payable and accrued current liabilities	2	11
Current portion long-term debt, including, capital leases	196	177
Current regulatory liabilities	48	50
Other current liabilities	0	0
Mortgage bonds, notes and other	0	0
Securitization bonds	105	302
Capital lease obligations	0	0
Other long term liabilities	8	7
Total Liabilities	359	547
Variable Interest Entity, Primary Beneficiary [Member]
Assets [Abstract]
Cash and cash equivalents	10	10
Restricted cash	7	7
Accounts receivable	17	7
Inventories	112	141
Other current assets	1	1
Property, plant and equipment	100	93
Securitized regulatory assets	0	0
Other assets	9	11
Total Assets	256	270
Liabilities [Abstract]
Accounts payable and accrued current liabilities	35	14
Current portion long-term debt, including, capital leases	9	8
Current regulatory liabilities	0	0
Other current liabilities	3	4
Mortgage bonds, notes and other	22	25
Securitization bonds	0	0
Capital lease obligations	7	11
Other long term liabilities	3	2
Total Liabilities	79	64
Consolidated Variable Interest Entity [Member]
Assets [Abstract]
Cash and cash equivalents	10	10
Restricted cash	51	109
Accounts receivable	56	41
Inventories	112	141
Other current assets	1	1
Property, plant and equipment	100	93
Securitized regulatory assets	280	413
Other assets	14	18
Total Assets	624	826
Liabilities [Abstract]
Accounts payable and accrued current liabilities	37	25
Current portion long-term debt, including, capital leases	205	185
Current regulatory liabilities	48	50
Other current liabilities	3	4
Mortgage bonds, notes and other	22	25
Securitization bonds	105	302
Capital lease obligations	7	11
Other long term liabilities	11	9
Total Liabilities	$438	$611

Organization_and_Basis_of_Pres3

Organization and Basis of Presentation (Details 1) (USD $)	Sep. 30, 2013	Dec. 31, 2012
In Millions, unless otherwise specified
Variable Interest Entity, Nonconsolidated, Carrying Amount, Assets and Liabilities, Net [Abstract]
Notes receivable	$104	$112
Unconsolidated Variable Interest Entity [Member]
Variable Interest Entity, Nonconsolidated, Carrying Amount, Assets and Liabilities, Net [Abstract]
Other investments	138	130
Notes receivable	$3	$6

Organization_and_Basis_of_Pres4

Organization and Basis of Presentation (Details Textuals) (USD $)	Sep. 30, 2013
In Millions, unless otherwise specified	customers
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Number of Electric Customers	2,100,000
Number of Gas Customers	1,200,000
Significant Potential Exposure to Loss Due to VIE Long-Term Purchase Contracts	$0

Significant_Accounting_Policie3

Significant Accounting Policies (Details) (USD $)	3 Months Ended		9 Months Ended
In Millions, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated Other Comprehensive Loss	($155)		($158)
Other Comprehensive Income Before Reclassifications	2		0
Amounts Reclassified From Accumulated Other Comprehensive Income	2		7
Other Comprehensive Income (Loss), Net of Tax	4	4	7	11
Accumulated Other Comprehensive Loss	-151		-151
Accumulated Net Gain (Loss) from Designated or Qualifying Cash Flow Hedges [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated Other Comprehensive Loss	-4		-4
Other Comprehensive Income Before Reclassifications	0		0
Amounts Reclassified From Accumulated Other Comprehensive Income	0		0
Other Comprehensive Income (Loss), Net of Tax	0		0
Accumulated Other Comprehensive Loss	-4		-4
Accumulated Net Unrealized Investment Gain (Loss) [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated Other Comprehensive Loss	-8		-8
Other Comprehensive Income Before Reclassifications	1		1
Amounts Reclassified From Accumulated Other Comprehensive Income	0		0
Other Comprehensive Income (Loss), Net of Tax	1		1
Accumulated Other Comprehensive Loss	-7		-7
Accumulated Defined Benefit Plans Adjustment [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated Other Comprehensive Loss	-143		-148
Other Comprehensive Income Before Reclassifications	0		0
Amounts Reclassified From Accumulated Other Comprehensive Income	2		7
Other Comprehensive Income (Loss), Net of Tax	2		7
Accumulated Other Comprehensive Loss	-141		-141
Accumulated Translation Adjustment [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated Other Comprehensive Loss	0		2
Other Comprehensive Income Before Reclassifications	1		-1
Amounts Reclassified From Accumulated Other Comprehensive Income	0		0
Other Comprehensive Income (Loss), Net of Tax	-1		-1
Accumulated Other Comprehensive Loss	$1		$1

Significant_Accounting_Policie4

Significant Accounting Policies (Details 1) (USD $)	Sep. 30, 2013	Dec. 31, 2012
In Millions, unless otherwise specified
Finite-Lived Intangible Assets [Line Items]
Intangible Assets, Gross	$177	$189
Less: Accumulated Amortization	41	34
Intangible Assets, Net	136	155
Less current intangible assets	14	20
Finite-Lived Intangible Assets, Net	122	135
Emission Allowances [Member]
Finite-Lived Intangible Assets [Line Items]
Intangible Assets, Gross	3	6
Renewable Energy Credits [Member]
Finite-Lived Intangible Assets [Line Items]
Intangible Assets, Gross	48	44
Contractual Rights [Member]
Finite-Lived Intangible Assets [Line Items]
Intangible Assets, Gross	$126	$139

Significant_Accounting_Policie5

Significant Accounting Policies (Details Textuals) (USD $)	3 Months Ended		9 Months Ended
In Millions, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Significant Accounting Policies [Line Items]
Effective Income Tax Rate, Continuing Operations	28.00%	32.00%	29.00%	32.00%
Unrecognized Tax Benefits	$3		$3
Time Period of Decrease in Unrecognized Tax Benefits			12 months
Minimum [Member]
Significant Accounting Policies [Line Items]
Finite Lived Asset Useful Life			3 years
Maximum [Member]
Significant Accounting Policies [Line Items]
Finite Lived Asset Useful Life			30 years
Unrecognized Tax Benefits, Decreases Resulting from Settlements with Taxing Authorities			$1

Fair_Value_Details

Fair Value (Details) (USD $)	Sep. 30, 2013	Dec. 31, 2012
In Millions, unless otherwise specified
Assets [Abstract]
Nuclear decommissioning trusts	($1,139)	($1,037)
Liabilities [Abstract]
Derivative Liabilities, Current	58	125
Derivative Liabilities, Noncurrent	21	26
Fair Value, Measurements, Recurring [Member]
Assets [Abstract]
Cash and Cash Equivalents, Fair Value Disclosure	-68	-123
Nuclear decommissioning trusts	-1,139	-1,037
Other investments	-124	-110
Derivative assets [Abstract]
Derivative Assets	-98	-147
Assets, Fair Value Disclosure	-1,429	-1,417
Liabilities [Abstract]
Interest Rate Derivative Liabilities, at Fair Value	0	1
Derivative Liabilities	79	151
Financial and Nonfinancial Liabilities, Fair Value Disclosure	1,350	1,266
Fair Value, Measurements, Recurring [Member] | Natural Gas Commodity Contract [Member]
Derivative assets [Abstract]
Derivative Assets	-9	-40
Liabilities [Abstract]
Derivative Liabilities	26	56
Fair Value, Measurements, Recurring [Member] | Electricity [Member]
Derivative assets [Abstract]
Derivative Assets	-82	-102
Liabilities [Abstract]
Derivative Liabilities	51	93
Fair Value, Measurements, Recurring [Member] | Other Commodity Contract [Member]
Derivative assets [Abstract]
Derivative Assets	-7	-5
Liabilities [Abstract]
Derivative Liabilities	2	1
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member]
Assets [Abstract]
Cash and Cash Equivalents, Fair Value Disclosure	0	0
Nuclear decommissioning trusts	-757	-694
Other investments	-76	-66
Derivative assets [Abstract]
Derivative Assets	-436	-561
Assets, Fair Value Disclosure	-1,269	-1,321
Liabilities [Abstract]
Interest Rate Derivative Liabilities, at Fair Value	0	0
Derivative Liabilities	426	532
Financial and Nonfinancial Liabilities, Fair Value Disclosure	843	789
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member] | Natural Gas Commodity Contract [Member]
Derivative assets [Abstract]
Derivative Assets	-388	-555
Liabilities [Abstract]
Derivative Liabilities	374	526
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member] | Electricity [Member]
Derivative assets [Abstract]
Derivative Assets	0	0
Liabilities [Abstract]
Derivative Liabilities	0	0
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member] | Other Commodity Contract [Member]
Derivative assets [Abstract]
Derivative Assets	-48	-6
Liabilities [Abstract]
Derivative Liabilities	52	6
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member]
Assets [Abstract]
Cash and Cash Equivalents, Fair Value Disclosure	-68	-123
Nuclear decommissioning trusts	-382	-343
Other investments	-48	-44
Derivative assets [Abstract]
Derivative Assets	-280	-295
Assets, Fair Value Disclosure	-778	-805
Liabilities [Abstract]
Interest Rate Derivative Liabilities, at Fair Value	0	1
Derivative Liabilities	258	315
Financial and Nonfinancial Liabilities, Fair Value Disclosure	520	490
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member] | Natural Gas Commodity Contract [Member]
Derivative assets [Abstract]
Derivative Assets	-61	-66
Liabilities [Abstract]
Derivative Liabilities	49	73
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member] | Electricity [Member]
Derivative assets [Abstract]
Derivative Assets	-210	-226
Liabilities [Abstract]
Derivative Liabilities	204	240
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member] | Other Commodity Contract [Member]
Derivative assets [Abstract]
Derivative Assets	-9	-3
Liabilities [Abstract]
Derivative Liabilities	5	1
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 3 [Member]
Assets [Abstract]
Cash and Cash Equivalents, Fair Value Disclosure	0	0
Nuclear decommissioning trusts	0	0
Other investments	0	0
Derivative assets [Abstract]
Derivative Assets	-127	-160
Assets, Fair Value Disclosure	-127	-160
Liabilities [Abstract]
Interest Rate Derivative Liabilities, at Fair Value	0	0
Derivative Liabilities	131	173
Financial and Nonfinancial Liabilities, Fair Value Disclosure	-4	-13
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 3 [Member] | Natural Gas Commodity Contract [Member]
Derivative assets [Abstract]
Derivative Assets	-34	-24
Liabilities [Abstract]
Derivative Liabilities	48	62
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 3 [Member] | Electricity [Member]
Derivative assets [Abstract]
Derivative Assets	-88	-134
Liabilities [Abstract]
Derivative Liabilities	83	111
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 3 [Member] | Other Commodity Contract [Member]
Derivative assets [Abstract]
Derivative Assets	-5	-2
Liabilities [Abstract]
Derivative Liabilities	0	0
Fair Value, Measurements, Recurring [Member] | Netting [Member]
Assets [Abstract]
Cash and Cash Equivalents, Fair Value Disclosure	0	0
Nuclear decommissioning trusts	0	0
Other investments	0	0
Derivative assets [Abstract]
Derivative Assets	-745	-869
Assets, Fair Value Disclosure	-745	-869
Liabilities [Abstract]
Interest Rate Derivative Liabilities, at Fair Value	0	0
Derivative Liabilities	736	869
Financial and Nonfinancial Liabilities, Fair Value Disclosure	9	0
Fair Value, Measurements, Recurring [Member] | Netting [Member] | Natural Gas Commodity Contract [Member]
Derivative assets [Abstract]
Derivative Assets	-474	-605
Liabilities [Abstract]
Derivative Liabilities	445	605
Fair Value, Measurements, Recurring [Member] | Netting [Member] | Electricity [Member]
Derivative assets [Abstract]
Derivative Assets	-216	-258
Liabilities [Abstract]
Derivative Liabilities	236	258
Fair Value, Measurements, Recurring [Member] | Netting [Member] | Other Commodity Contract [Member]
Derivative assets [Abstract]
Derivative Assets	-55	-6
Liabilities [Abstract]
Derivative Liabilities	55	6
Current Asset [Member] | Fair Value, Measurements, Recurring [Member]
Derivative assets [Abstract]
Assets, Fair Value Disclosure	-140	-231
Current Asset [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member]
Derivative assets [Abstract]
Assets, Fair Value Disclosure	-400	-493
Current Asset [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member]
Derivative assets [Abstract]
Assets, Fair Value Disclosure	-285	-372
Current Asset [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 3 [Member]
Derivative assets [Abstract]
Assets, Fair Value Disclosure	-94	-120
Current Asset [Member] | Fair Value, Measurements, Recurring [Member] | Netting [Member]
Derivative assets [Abstract]
Assets, Fair Value Disclosure	-639	-754
Non Current Asset [Member] | Fair Value, Measurements, Recurring [Member]
Derivative assets [Abstract]
Assets, Fair Value Disclosure	-1,289	-1,186
Non Current Asset [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member]
Derivative assets [Abstract]
Assets, Fair Value Disclosure	-869	-828
Non Current Asset [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member]
Derivative assets [Abstract]
Assets, Fair Value Disclosure	-493	-433
Non Current Asset [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 3 [Member]
Derivative assets [Abstract]
Assets, Fair Value Disclosure	-33	-40
Non Current Asset [Member] | Fair Value, Measurements, Recurring [Member] | Netting [Member]
Derivative assets [Abstract]
Assets, Fair Value Disclosure	-106	-115
Current Liability [Member] | Fair Value, Measurements, Recurring [Member]
Liabilities [Abstract]
Derivative Liabilities, Current	58	125
Current Liability [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member]
Liabilities [Abstract]
Derivative Liabilities, Current	379	466
Current Liability [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member]
Liabilities [Abstract]
Derivative Liabilities, Current	189	269
Current Liability [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 3 [Member]
Liabilities [Abstract]
Derivative Liabilities, Current	100	144
Current Liability [Member] | Fair Value, Measurements, Recurring [Member] | Netting [Member]
Liabilities [Abstract]
Derivative Liabilities, Current	610	754
Noncurrent Liability [Member] | Fair Value, Measurements, Recurring [Member]
Liabilities [Abstract]
Derivative Liabilities, Noncurrent	21	26
Noncurrent Liability [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member]
Liabilities [Abstract]
Derivative Liabilities, Noncurrent	47	66
Noncurrent Liability [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member]
Liabilities [Abstract]
Derivative Liabilities, Noncurrent	69	46
Noncurrent Liability [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 3 [Member]
Liabilities [Abstract]
Derivative Liabilities, Noncurrent	31	29
Noncurrent Liability [Member] | Fair Value, Measurements, Recurring [Member] | Netting [Member]
Liabilities [Abstract]
Derivative Liabilities, Noncurrent	126	115
Other Investments [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member]
Assets [Abstract]
Cash and Cash Equivalents, Fair Value Disclosure	-17	-14
Other Investments [Member] | Equity [Member] | Fair Value, Measurements, Recurring [Member]
Assets [Abstract]
Other investments	($124)	($110)

Fair_Value_Details_1

Fair Value (Details 1) (USD $)	3 Months Ended		9 Months Ended
In Millions, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Fair value reconciliation of Level 3 assets and liabilities measured at fair value on a recurring basis
Beginning Balance	($16)	$57	($13)	$44
Transfers into Level 3	0	0	0	29
Transfer out of Level 3	1	0	2	-2
Total gains (losses): [Abstract]
Included in earnings	25	-30	43	15
Recorded in regulatory assets/liabilities	3	7	7	12
Purchases issuances and settlements [Abstract]
Purchases			-1	1
Settlements	-15	-48	-38	-113
Ending Balance	-4	-14	-4	-14
The amount of total gains (losses) included in net income attributed to the change in unrealized gains or losses related to assets still held at the end of the period	0	-37	22	4
Natural Gas Commodity Contract [Member]
Fair value reconciliation of Level 3 assets and liabilities measured at fair value on a recurring basis
Beginning Balance	-30	2	-38	6
Transfers into Level 3	0	0	0	1
Transfer out of Level 3	0	0	2	-2
Total gains (losses): [Abstract]
Included in earnings	8	-43	-1	-38
Recorded in regulatory assets/liabilities	0	0	0	0
Purchases issuances and settlements [Abstract]
Purchases			0	0
Settlements	8	-3	27	-11
Ending Balance	-14	-44	-14	-44
The amount of total gains (losses) included in net income attributed to the change in unrealized gains or losses related to assets still held at the end of the period	-8	-43	-14	-39
Electricity [Member]
Fair value reconciliation of Level 3 assets and liabilities measured at fair value on a recurring basis
Beginning Balance	12	50	23	32
Transfers into Level 3	0	0	0	28
Transfer out of Level 3	1	0	0	0
Total gains (losses): [Abstract]
Included in earnings	17	12	44	53
Recorded in regulatory assets/liabilities	0	0	0	0
Purchases issuances and settlements [Abstract]
Purchases			-1	1
Settlements	-23	-38	-61	-90
Ending Balance	5	24	5	24
The amount of total gains (losses) included in net income attributed to the change in unrealized gains or losses related to assets still held at the end of the period	8	5	36	43
Other Commodity Contract [Member]
Fair value reconciliation of Level 3 assets and liabilities measured at fair value on a recurring basis
Beginning Balance	2	5	2	6
Transfers into Level 3	0	0	0	0
Transfer out of Level 3	0	0	0	0
Total gains (losses): [Abstract]
Included in earnings	0	1	0	0
Recorded in regulatory assets/liabilities	3	7	7	12
Purchases issuances and settlements [Abstract]
Purchases			0	0
Settlements	0	-7	-4	-12
Ending Balance	5	6	5	6
The amount of total gains (losses) included in net income attributed to the change in unrealized gains or losses related to assets still held at the end of the period	$0	$1	$0	$0

Fair_Value_Fair_Value_Details_

Fair Value Fair Value (Details 2) (USD $)	3 Months Ended		9 Months Ended
In Millions, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Fair Value Transfers Between Level 1, Level 2 and Level 3 [Line Items]
Transfers from Level 2 to Level 1	$0	$0	$0	$0
Transfers from Level 3 to Level 1	0	0	0	0
Transfers from Level 1 to Level 2	0	0	0	0
Transfers from Level 3 to Level 2	1	0	2	2
Transfers from Level 1 to Level 3	0	0	0	0
Transfers from Level 2 to Level 3	$0	$0	$0	$29

Fair_Value_Fair_Value_Details_1

Fair Value Fair Value (Details 3) (USD $)	Sep. 30, 2013	Dec. 31, 2012
In Millions, unless otherwise specified	MMBTU	MMBTU
Fair Value, Inputs, Level 3 [Member] | Natural Gas Commodity Contract [Member]
Unobservable Inputs Valuation Techniques [Line Items]
Derivative Weighted Average Forward Basis Price	0.1	0.03
Fair Value, Inputs, Level 3 [Member] | Electricity [Member]
Unobservable Inputs Valuation Techniques [Line Items]
Derivative Weighted Average Forward Basis Price	2	3
Minimum [Member] | Fair Value, Inputs, Level 3 [Member] | Natural Gas Commodity Contract [Member]
Unobservable Inputs Valuation Techniques [Line Items]
Forward basis price	-1.1	-0.63
Minimum [Member] | Fair Value, Inputs, Level 3 [Member] | Electricity [Member]
Unobservable Inputs Valuation Techniques [Line Items]
Forward basis price	-8	-2
Maximum [Member] | Fair Value, Inputs, Level 3 [Member] | Natural Gas Commodity Contract [Member]
Unobservable Inputs Valuation Techniques [Line Items]
Forward basis price	4.22	1.95
Maximum [Member] | Fair Value, Inputs, Level 3 [Member] | Electricity [Member]
Unobservable Inputs Valuation Techniques [Line Items]
Forward basis price	15	16
Fair Value, Measurements, Recurring [Member]
Unobservable Inputs Valuation Techniques [Line Items]
Derivative Assets	98	147
Derivative Liabilities	-79	-151
Fair Value, Measurements, Recurring [Member] | Natural Gas Commodity Contract [Member]
Unobservable Inputs Valuation Techniques [Line Items]
Derivative Assets	9	40
Derivative Liabilities	-26	-56
Fair Value, Measurements, Recurring [Member] | Electricity [Member]
Unobservable Inputs Valuation Techniques [Line Items]
Derivative Assets	82	102
Derivative Liabilities	-51	-93
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 3 [Member]
Unobservable Inputs Valuation Techniques [Line Items]
Derivative Assets	127	160
Derivative Liabilities	-131	-173
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 3 [Member] | Natural Gas Commodity Contract [Member]
Unobservable Inputs Valuation Techniques [Line Items]
Derivative Assets	34	24
Derivative Liabilities	-48	-62
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 3 [Member] | Electricity [Member]
Unobservable Inputs Valuation Techniques [Line Items]
Derivative Assets	88	134
Derivative Liabilities	-83	-111

Fair_Value_Fair_Value_Details_2

Fair Value Fair Value (Details 4) (USD $)	Sep. 30, 2013	Dec. 31, 2012
In Millions, unless otherwise specified
Fair Value of Financial Instruments [Line Items]
Notes Receivable Excudling Capital Leases	$37	$39
Dividends payable	116	107
Short-term Debt	271	240
Long-term Debt	7,729	7,813
Fair Value, Inputs, Level 1 [Member]
Fair Value of Financial Instruments [Line Items]
Notes Receivable, Fair Value Disclosure	0	0
Dividends Payable Fair Value Disclosure	116	107
Short-term Debt, Fair Value	0	0
Long-term Debt, Fair Value	436	507
Fair Value, Inputs, Level 2 [Member]
Fair Value of Financial Instruments [Line Items]
Notes Receivable, Fair Value Disclosure	0	0
Dividends Payable Fair Value Disclosure	0	0
Short-term Debt, Fair Value	271	240
Long-term Debt, Fair Value	7,067	7,453
Fair Value, Inputs, Level 3 [Member]
Fair Value of Financial Instruments [Line Items]
Notes Receivable, Fair Value Disclosure	37	39
Dividends Payable Fair Value Disclosure	0	0
Short-term Debt, Fair Value	0	0
Long-term Debt, Fair Value	$738	$933

Fair_Value_Details_5

Fair Value (Details 5) (USD $)	Sep. 30, 2013	Dec. 31, 2012
In Millions, unless otherwise specified
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Decommissioning Fund Investments	$1,139	$1,037
Fermi 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Decommissioning Fund Investments	1,120	1,021
Fermi 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Decommissioning Fund Investments	3	3
Low level radioactive waste [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Decommissioning Fund Investments	$16	$13

Fair_Value_Details_6

Fair Value (Details 6) (Nuclear Decommissioning Trust Fund [Member], USD $)	3 Months Ended		9 Months Ended
In Millions, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Nuclear Decommissioning Trust Fund [Member]
Fair Value, Option, Quantitative Disclosures [Line Items]
Realized gains	$11	$7	$30	$21
Realized losses	-11	-6	-25	-17
Proceeds from sales of securities	$13	$12	$40	$48

Fair_Value_Details_7

Fair Value (Details 7) (USD $)	9 Months Ended	12 Months Ended
In Millions, unless otherwise specified	Sep. 30, 2013	Dec. 31, 2012
Fair Value, Option, Quantitative Disclosures [Line Items]
Nuclear decommissioning trusts	$1,139	$1,037
Unrealized Gains	212	149
Nuclear Decommissioning Trust Fund [Member]
Fair Value, Option, Quantitative Disclosures [Line Items]
Cash and Cash Equivalents	12	7
Nuclear Decommissioning Trust Fund [Member] | Equity securities [Member]
Fair Value, Option, Quantitative Disclosures [Line Items]
Equity securities	732	631
Unrealized Gains	195	122
Nuclear Decommissioning Trust Fund [Member] | Debt securities [Member]
Fair Value, Option, Quantitative Disclosures [Line Items]
Debt securities	395	399
Unrealized Gains	17	27
Nuclear Decommissioning Trust Fund [Member] | Cash and cash equivalents [Member]
Fair Value, Option, Quantitative Disclosures [Line Items]
Unrealized Gains	$0	$0

Fair_Value_Details_Textuals

Fair Value (Details Textuals) (USD $)

3 Months Ended

9 Months Ended

9 Months Ended

12 Months Ended

3 Months Ended

9 Months Ended

Sep. 30, 2013

Sep. 30, 2012

Sep. 30, 2013

Sep. 30, 2012

Sep. 30, 2013

Dec. 31, 2012

Sep. 30, 2013

Dec. 31, 2012

Sep. 30, 2013

Dec. 31, 2012

Sep. 30, 2013

Dec. 31, 2012

Sep. 30, 2013

Dec. 31, 2012

Sep. 30, 2013

Dec. 31, 2012

Sep. 30, 2013

Dec. 31, 2012

Sep. 30, 2013

Sep. 30, 2012

Sep. 30, 2013

Sep. 30, 2012

Fair Value, Measurements, Recurring [Member]

Fair Value, Measurements, Recurring [Member]

Fair Value, Inputs, Level 2 [Member]

Fair Value, Inputs, Level 2 [Member]

Restricted Assets [Member]

Restricted Assets [Member]

Other Investments [Member]

Other Investments [Member]

Other Investments [Member]

Other Investments [Member]

Nuclear Decommissioning Trust Fund [Member]

Nuclear Decommissioning Trust Fund [Member]

Fermi 2 [Member]

Fermi 2 [Member]

Fermi 1 [Member]

Fermi 1 [Member]

Fermi 1 [Member]

Fermi 1 [Member]

Fair Value, Measurements, Recurring [Member]

Fair Value, Measurements, Recurring [Member]

Fair Value, Inputs, Level 2 [Member]

Fair Value, Inputs, Level 2 [Member]

Fair Value, Measurements, Recurring [Member]

Fair Value, Measurements, Recurring [Member]

Fair Value, Inputs, Level 2 [Member]

Fair Value, Inputs, Level 2 [Member]

Fair Value, Measurements, Recurring [Member]

Fair Value, Measurements, Recurring [Member]

Equity [Member]

Equity [Member]

Fair Value, Measurements, Recurring [Member]

Fair Value, Measurements, Recurring [Member]

Fair Value, Option, Quantitative Disclosures [Line Items]

Cash and Cash Equivalents, Fair Value Disclosure

$68,000,000

$123,000,000

$68,000,000

$123,000,000

$51,000,000

$109,000,000

$17,000,000

$14,000,000

$12,000,000

$7,000,000

Available-for-sale Securities, Fair Value Disclosure

6,000,000

5,000,000

Other investments

124,000,000

110,000,000

48,000,000

44,000,000

124,000,000

110,000,000

Average Maturity of Debt Securities

7 years

6 years

Unrealized losses recognized as regulatory assets

38,000,000

44,000,000

Fermi I Corresponding Regulatory Asset Treatment

0

0

Unrealized losses recognized in earnings

0

0

0

0

Unrealized on Available for Sale Securities

0

0

0

0

Trading Securities, Change in Unrealized Holding Gain (Loss)

$14,000,000

$11,000,000

Financial_and_Other_Derivative2

Financial and Other Derivative Instruments (Details) (USD $)	Sep. 30, 2013	Dec. 31, 2012
In Millions, unless otherwise specified
Derivatives designated as hedging instruments:
Derivative Asset Fair Value Gross Asset	$843	$1,016
Derivative Liability Fair Value Gross Liability	-815	-1,020
Derivative Assets, Current	72	108
Derivative Assets, Noncurrent	26	39
Derivative Liabilities, Current	-58	-125
Derivative Liabilities, Noncurrent	-21	-26
Estimate of Fair Value, Fair Value Disclosure [Member]
Derivatives designated as hedging instruments:
Derivative Assets, Current	711	862
Derivative Assets, Noncurrent	132	154
Derivative Liabilities, Current	-668	-879
Derivative Liabilities, Noncurrent	-147	-141
Interest rate contracts [Member]
Derivatives designated as hedging instruments:
Derivative Liability Fair Value Gross Liability	0	-1
Natural Gas Commodity Contract [Member]
Derivatives designated as hedging instruments:
Derivative Asset Fair Value Gross Asset	483	645
Derivative Liability Fair Value Gross Liability	-471	-661
Electricity [Member]
Derivatives designated as hedging instruments:
Derivative Asset Fair Value Gross Asset	298	360
Derivative Liability Fair Value Gross Liability	-287	-351
Designated as Hedging Instrument [Member] | Interest rate contracts [Member]
Derivatives designated as hedging instruments:
Derivative Asset Fair Value Gross Asset	0	0
Derivative Liability Fair Value Gross Liability	0	-1
Not Designated as Hedging Instrument [Member]
Derivatives designated as hedging instruments:
Derivative Asset Fair Value Gross Asset	843	1,016
Derivative Liability Fair Value Gross Liability	-815	-1,019
Not Designated as Hedging Instrument [Member] | Natural Gas Commodity Contract [Member]
Derivatives designated as hedging instruments:
Derivative Asset Fair Value Gross Asset	483	645
Derivative Liability Fair Value Gross Liability	-471	-661
Not Designated as Hedging Instrument [Member] | Electricity [Member]
Derivatives designated as hedging instruments:
Derivative Asset Fair Value Gross Asset	298	360
Derivative Liability Fair Value Gross Liability	-287	-351
Not Designated as Hedging Instrument [Member] | Other [Member]
Derivatives designated as hedging instruments:
Derivative Asset Fair Value Gross Asset	62	11
Derivative Liability Fair Value Gross Liability	($57)	($7)

Financial_and_Other_Derivative3

Financial and Other Derivative Instruments Financial and Other Derivative Instruments (Details 1) (USD $)	Sep. 30, 2013	Dec. 31, 2012
In Millions, unless otherwise specified
Netting Offsets of Derivative Assets and Liabilities [Line Items]
Derivative Asset, Fair Value, Gross Asset	$843	$1,016
Gross Amounts Offset in the Statements of Financial Position	-745	-869
Net Amounts of Assets Presented in the Statements of Financial Position	98	147
Fair Value Gross Amounts of Recognized Liabilities	-815	-1,020
Gross Amounts Offset in the Statement of Financial Position	736	869
Net Amounts of Liabilities Presented in the Statements of Financial Position	-79	-151
Natural Gas Commodity Contract [Member]
Netting Offsets of Derivative Assets and Liabilities [Line Items]
Derivative Asset, Fair Value, Gross Asset	483	645
Gross Amounts Offset in the Statements of Financial Position	-474	-605
Net Amounts of Assets Presented in the Statements of Financial Position	9	40
Fair Value Gross Amounts of Recognized Liabilities	-471	-661
Gross Amounts Offset in the Statement of Financial Position	445	605
Net Amounts of Liabilities Presented in the Statements of Financial Position	-26	-56
Electricity [Member]
Netting Offsets of Derivative Assets and Liabilities [Line Items]
Derivative Asset, Fair Value, Gross Asset	298	360
Gross Amounts Offset in the Statements of Financial Position	-216	-258
Net Amounts of Assets Presented in the Statements of Financial Position	82	102
Fair Value Gross Amounts of Recognized Liabilities	-287	-351
Gross Amounts Offset in the Statement of Financial Position	236	258
Net Amounts of Liabilities Presented in the Statements of Financial Position	-51	-93
Other Contract [Member]
Netting Offsets of Derivative Assets and Liabilities [Line Items]
Derivative Asset, Fair Value, Gross Asset	62	11
Gross Amounts Offset in the Statements of Financial Position	-55	-6
Net Amounts of Assets Presented in the Statements of Financial Position	7	5
Fair Value Gross Amounts of Recognized Liabilities	-57	-7
Gross Amounts Offset in the Statement of Financial Position	55	6
Net Amounts of Liabilities Presented in the Statements of Financial Position	-2	-1
Interest rate contracts [Member]
Netting Offsets of Derivative Assets and Liabilities [Line Items]
Fair Value Gross Amounts of Recognized Liabilities	0	-1
Gross Amounts Offset in the Statement of Financial Position	0	0
Net Amounts of Liabilities Presented in the Statements of Financial Position	$0	($1)

Financial_and_Other_Derivative4

Financial and Other Derivative Instruments Financial and Other Derivative Instruments (Details 2) (USD $)	Sep. 30, 2013	Dec. 31, 2012
In Millions, unless otherwise specified
Derivative [Line Items]
Derivative Assets, Current	$72	$108
Derivative Assets, Noncurrent	26	39
Derivative Liabilities, Current	-58	-125
Derivative Liabilities, Noncurrent	-21	-26
Derivative Asset [Member]
Derivative [Line Items]
Derivative Assets, Current	711	862
Derivative Assets, Noncurrent	132	154
Derivative Liabilities [Member]
Derivative [Line Items]
Derivative Liabilities, Current	-668	-879
Derivative Liabilities, Noncurrent	-147	-141
Counterparty Netting [Member]
Derivative [Line Items]
Derivative Assets, Current	-610	-754
Derivative Assets, Noncurrent	-106	-115
Derivative Liabilities, Current	-610	-754
Derivative Liabilities, Noncurrent	-106	-115
Collateral Adjustment [Member]
Derivative [Line Items]
Derivative Assets, Current	-29	0
Derivative Assets, Noncurrent	0	0
Derivative Liabilities, Current	0	0
Derivative Liabilities, Noncurrent	-20	0
Derivative [Member]
Derivative [Line Items]
Derivative Assets, Current	72	108
Derivative Assets, Noncurrent	26	39
Derivative Liabilities, Current	-58	-125
Derivative Liabilities, Noncurrent	($21)	($26)

Financial_and_Other_Derivative5

Financial and Other Derivative Instruments (Details 3) (USD $)	3 Months Ended		9 Months Ended
In Millions, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Derivative Instruments, Gain (Loss) [Line Items]
Derivative Instruments Not Designated as Hedging Instruments, Gain (Loss), Net	$23	$12	$56	$57
Foreign currency exchange contracts [Member] | Operating Revenue [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative Instruments Not Designated as Hedging Instruments, Gain (Loss), Net	0	-2	-1	-1
Natural Gas Commodity Contract [Member] | Operating Revenue [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative Instruments Not Designated as Hedging Instruments, Gain (Loss), Net	1	-54	37	-51
Natural Gas Commodity Contract [Member] | Fuel, purchased power and gas [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative Instruments Not Designated as Hedging Instruments, Gain (Loss), Net	-1	50	-33	45
Electricity [Member] | Operating Revenue [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative Instruments Not Designated as Hedging Instruments, Gain (Loss), Net	22	17	52	52
Other [Member] | Operating Revenue [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative Instruments Not Designated as Hedging Instruments, Gain (Loss), Net	$1	$1	$1	$12

Financial_and_Other_Derivative6

Financial and Other Derivative Instruments (Details 4)	Sep. 30, 2013
	dte.volumes
Natural Gas Commodity Contract [Member]
Derivative [Line Items]
Volume of Commodity Contracts	683,113,433
Electricity [Member]
Derivative [Line Items]
Volume of Commodity Contracts	59,672,654
Foreign currency exchange contracts [Member]
Derivative [Line Items]
Volume of Commodity Contracts	48,741,288
FTR [Member]
Derivative [Line Items]
Volume of Commodity Contracts	13,005,024

Financial_and_Other_Derivative7

Financial and Other Derivative Instruments (Details Textuals) (USD $)	Sep. 30, 2013	Dec. 31, 2012	Sep. 30, 2013	Sep. 30, 2013
			FTR [Member]	FTR [Member]
Derivative [Line Items]
Interest Rate Cash Flow Hedge Gain (Loss) to be Reclassified During Next 12 Months, Net	$1,000,000
Letters of Credit Outstanding, Amount	21,000,000	63,000,000
Cash Collateral Posted Net of Cash Collateral Received	30,000,000
Collateral Already Posted, Aggregate Fair Value		20,000,000
Cash Collateral Paid or Received for Derivative Assets	29,000,000	0
Cash Collateral Paid or Received for Derivative Liabilities	20,000,000
Cash Collateral Received	24,000,000	24,000,000
Cash Collateral Paid	3,000,000	4,000,000
Effect of Derivative Instruments Recoverable Through PSCR Mechanism			3,000,000	7,000,000
Value of Transactions Company Would Have Been Exposed to if Credit Rating Below Investment Grade	$327,000,000

Discontinued_Operations_Discon1

Discontinued Operations Discontinued Operations (Details) (Discontinued Operations [Member], USD $)	3 Months Ended	9 Months Ended
In Millions, unless otherwise specified	Sep. 30, 2012	Sep. 30, 2012
Discontinued Operations [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Operating Revenue	$16	$38
Operation and Maintenance	6	16
Depreciation, Depletion and Amortization	6	17
Taxes, Other	1	2
Operating Income (Loss)	3	3
Other (Income) and Deductions	-1	-4
Taxes other than Income	1	-1
Income (Loss) from Discontinued Operations, Net of Tax, Attributable to Parent	$1	$0

Discontinued_Operations_Discon2

Discontinued Operations Discontinued Operations (Details Textuals)	Dec. 31, 2012
Discontinued Operations and Disposal Groups [Abstract]
Percentage of Equity Sold	100.00%

Asset_Retirement_Obligations_D

Asset Retirement Obligations (Details) (USD $)	9 Months Ended
In Millions, unless otherwise specified	Sep. 30, 2013
Asset Retirement Obligation Disclosure [Abstract]
Asset retirement obligations	$1,719
Accretion	79
Liabilities Incurred	1
Liabilities Settled	-12
Revision in estimated cash flows	13
Asset retirement obligations	$1,800

Regulatory_Matters_Details_Tex

Regulatory Matters (Details Textuals) (USD $)	Jul. 29, 2013	Mar. 31, 2013	Sep. 30, 2013	Oct. 17, 2013	Jul. 30, 2012	Sep. 30, 2013	Mar. 31, 2013	Jun. 30, 2013	Jun. 30, 2013
		MPSC [Member]	MPSC [Member]	MPSC [Member]	MPSC [Member]	MPSC [Member]	MPSC [Member]	Five Year (Minimum) [Member]	Seven Year (Maximum) [Member]
		Electric [Member]	Electric [Member]	Electric [Member]	Electric [Member]	Gas [Member]	Gas [Member]
Regulatory Asset and Liability [Line Items]
Years to transition PLD customers to DTE Electric distribution system								5 years	7 years
Rate increase previously authorized by the MPSC challeged by Court of Appeals affirmed by the MPSC				$8,000,000
Rate Base Amount related to Advanced Metering Infrasctructure Program reopened related to previously approved order			55,000,000
PSCR under-recovery from One Plan Year Prior		87,000,000
PSCR Under-Recovery from Two Plan Years Prior		148,000,000
Two Plan Years Prior PSCR Reconciliation included amount of Purchased Power Cost Related to Manual Shutdown of Fermi 2		30,000,000
Fermi 2 Production Level of Full Capacity					68.00%
Monthly Funding Factor for all Michigan Electric utilities participating in Low Income Energy Assistance Fund	0.99
Requesting Authority to Refund Uncollectible Expense to Customers							$20,000,000
Time Period to Refund the UETM Overrecovery						12 months

Common_Stock_Details

Common Stock (Details) (Pension Plan, Defined Benefit [Member], USD $)	3 Months Ended			9 Months Ended
In Millions, except Share data, unless otherwise specified	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Sep. 30, 2013	Sep. 12, 2013
Class of Stock [Line Items]
Pension Contributions				$250
Common Stock [Member]
Class of Stock [Line Items]
Pension Contributions	$100	$50	$50	$200
Contribution of Common Stock to Pension Plan Shares	1,522,301	753,579	750,075
Contribution of Common Stock to Pension Plans Amount Per Share		$66.35	$66.66		$65.69

Earnings_Per_Share_Details

Earnings Per Share (Details) (USD $)	3 Months Ended		9 Months Ended
In Millions, except Per Share data, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Basic Earnings per Share
Net Income Attributable to DTE Energy Company	$198	$227	$537	$529
Average number of common shares outstanding	175	172	174	171
Weighted average net restricted shares outstanding	0	1	1	1
Dividends declared on common stock	115	106	337	307
Dividends declared - net restricted shares	1	1	1	2
Total distributed earnings	116	107	338	309
Net income less distributed earnings	82	120	199	220
Distributed (dividends per common share)	$0.66	$0.62	$1.93	$1.80
Undistributed	$0.47	$0.70	$1.14	$1.29
Total Basic Earnings per Common Share	$1.13	$1.32	$3.07	$3.09
Diluted Earnings per Share
Net Income Attributable to DTE Energy Company	198	227	537	529
Average number of common shares outstanding	175	172	174	171
Average incremental shares from assumed exercise of options	0	0	0	0
Common shares for dilutive calculation	176	172	175	171
Weighted average net restricted shares outstanding	0	1	1	1
Dividends declared on common stock	115	106	337	307
Dividends declared - net restricted shares	1	1	1	2
Total distributed earnings	116	107	338	309
Net income less distributed earnings	$82	$120	$199	$220
Distributed (dividends per common share)	$0.66	$0.62	$1.93	$1.80
Undistributed	$0.47	$0.69	$1.14	$1.28
Total Diluted Earnings per Common Share	$1.13	$1.31	$3.07	$3.08

LongTerm_Debt_Details

Long-Term Debt (Details) (USD $)	Sep. 30, 2013	Mar. 31, 2013
In Millions, unless otherwise specified
Debt Instrument [Line Items]
Debt Instrument, Face Amount	$775
Electric [Member] | Mortgages [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	3.65%	4.00%
Debt Instrument, Face Amount	$400	$375

LongTerm_Debt_Details_1

Long-Term Debt (Details 1) (USD $)	9 Months Ended		3 Months Ended
In Millions, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2013	Jun. 30, 2013	Sep. 30, 2013	Mar. 31, 2013	Mar. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Jun. 30, 2013
		DTE Energy [Member]	DTE Energy [Member]	Electric [Member]	Electric [Member]	Electric [Member]	Electric [Member]	Electric [Member]	Gas [Member]
		Long-term Debt [Member]	Senior Notes [Member]	Securitization Bonds [Member]	Securitization Bonds [Member]	Tax Exempt Revenue Bonds [Member]	Senior Notes [Member]	Long Term Debt, Other [Member]	Senior Notes [Member]
Extinguishment of Debt [Line Items]
Debt Instrument, Interest Rate, Stated Percentage				6.62%	6.42%	5.30%	6.40%		5.26%
Extinguishment of Debt, Amount	$855	$4	$300	$89	$88	$51	$250	$13	$60

LongTerm_Debt_LongTerm_Debt_De

Long-Term Debt Long-Term Debt (Details Textuals) (Gas [Member], Mortgages [Member], USD $)	Sep. 30, 2013
In Millions, unless otherwise specified
Ten Years [Member]
Debt Instrument [Line Items]
Debt Instrument, Face Amount, Future Issuance	$50
Future Debt Instrument, Interest Rate, Stated Percentage	3.64%
Twelve Years [Member]
Debt Instrument [Line Items]
Debt Instrument, Face Amount, Future Issuance	70
Future Debt Instrument, Interest Rate, Stated Percentage	3.74%
Fifteen Years [Member]
Debt Instrument [Line Items]
Debt Instrument, Face Amount, Future Issuance	$50
Future Debt Instrument, Interest Rate, Stated Percentage	3.94%

ShortTerm_Credit_Arrangements_2

Short-Term Credit Arrangements and Borrowings (Details) (USD $)	Sep. 30, 2013
In Millions, unless otherwise specified
Availability under combined facilities
Line of Credit Facility, Maximum Borrowing Capacity	$1,975
Amounts Outstanding	506
Net availability	1,469
DTE Energy [Member]
Availability under combined facilities
Line of Credit Facility, Maximum Borrowing Capacity	1,375
Amounts Outstanding	279
Net availability	1,096
DTE Electric [Member]
Availability under combined facilities
Line of Credit Facility, Maximum Borrowing Capacity	300
Amounts Outstanding	11
Net availability	289
DTE Gas [Member]
Availability under combined facilities
Line of Credit Facility, Maximum Borrowing Capacity	300
Amounts Outstanding	216
Net availability	84
Letter of Credit [Member]
Availability under combined facilities
Amounts Outstanding	235
Letter of Credit [Member] | Unsecured letter of credit facility expiring in May 2014 [Member]
Availability under combined facilities
Line of Credit Facility, Maximum Borrowing Capacity	50
Letter of Credit [Member] | Unsecured letter of credit facility expiring in August 2015 [Member]
Availability under combined facilities
Line of Credit Facility, Maximum Borrowing Capacity	125
Letter of Credit [Member] | DTE Energy [Member]
Availability under combined facilities
Amounts Outstanding	235
Letter of Credit [Member] | DTE Energy [Member] | Unsecured letter of credit facility expiring in May 2014 [Member]
Availability under combined facilities
Line of Credit Facility, Maximum Borrowing Capacity	50
Letter of Credit [Member] | DTE Energy [Member] | Unsecured letter of credit facility expiring in August 2015 [Member]
Availability under combined facilities
Line of Credit Facility, Maximum Borrowing Capacity	125
Letter of Credit [Member] | DTE Electric [Member]
Availability under combined facilities
Amounts Outstanding	0
Letter of Credit [Member] | DTE Electric [Member] | Unsecured letter of credit facility expiring in May 2014 [Member]
Availability under combined facilities
Line of Credit Facility, Maximum Borrowing Capacity	0
Letter of Credit [Member] | DTE Electric [Member] | Unsecured letter of credit facility expiring in August 2015 [Member]
Availability under combined facilities
Line of Credit Facility, Maximum Borrowing Capacity	0
Letter of Credit [Member] | DTE Gas [Member]
Availability under combined facilities
Amounts Outstanding	0
Letter of Credit [Member] | DTE Gas [Member] | Unsecured letter of credit facility expiring in May 2014 [Member]
Availability under combined facilities
Line of Credit Facility, Maximum Borrowing Capacity	0
Letter of Credit [Member] | DTE Gas [Member] | Unsecured letter of credit facility expiring in August 2015 [Member]
Availability under combined facilities
Line of Credit Facility, Maximum Borrowing Capacity	0
Revolving Credit Facility [Member] | Unsecured revolving credit facility expiring in April 2018 [Member]
Availability under combined facilities
Line of Credit Facility, Maximum Borrowing Capacity	1,800
Revolving Credit Facility [Member] | DTE Energy [Member] | Unsecured revolving credit facility expiring in April 2018 [Member]
Availability under combined facilities
Line of Credit Facility, Maximum Borrowing Capacity	1,200
Revolving Credit Facility [Member] | DTE Electric [Member] | Unsecured revolving credit facility expiring in April 2018 [Member]
Availability under combined facilities
Line of Credit Facility, Maximum Borrowing Capacity	300
Revolving Credit Facility [Member] | DTE Gas [Member] | Unsecured revolving credit facility expiring in April 2018 [Member]
Availability under combined facilities
Line of Credit Facility, Maximum Borrowing Capacity	300
Commercial Paper [Member]
Availability under combined facilities
Amounts Outstanding	271
Commercial Paper [Member] | DTE Energy [Member]
Availability under combined facilities
Amounts Outstanding	44
Commercial Paper [Member] | DTE Electric [Member]
Availability under combined facilities
Amounts Outstanding	11
Commercial Paper [Member] | DTE Gas [Member]
Availability under combined facilities
Amounts Outstanding	$216

ShortTerm_Credit_Arrangements_3

Short-Term Credit Arrangements and Borrowings (Details Textuals) (USD $)	Sep. 30, 2013	Dec. 31, 2012
In Millions, unless otherwise specified
Short-term Debt [Line Items]
Revolving Credit Facilities with a Syndicate Number of Banks	19
Number of Banks that Provide Percentage of Commitment in any Facility	1
Maximum Percentage of Commitment to Bank in any Facility	8.70%
Maximum Total Funded Debt to Total Capitalization Ratio	0.65
Other outstanding letters of credit	$506
DTE Energy [Member]
Short-term Debt [Line Items]
Total Funded Debt to Total Capitalization Ratio, Amount	0.48
Other outstanding letters of credit	279
DTE Electric [Member]
Short-term Debt [Line Items]
Total Funded Debt to Total Capitalization Ratio, Amount	0.53
Other outstanding letters of credit	11
DTE Gas [Member]
Short-term Debt [Line Items]
Total Funded Debt to Total Capitalization Ratio, Amount	0.44
Other outstanding letters of credit	216
Letter of Credit [Member]
Short-term Debt [Line Items]
Other outstanding letters of credit	235
Letter of Credit [Member] | DTE Energy [Member]
Short-term Debt [Line Items]
Other outstanding letters of credit	235
Letter of Credit [Member] | DTE Electric [Member]
Short-term Debt [Line Items]
Other outstanding letters of credit	0
Letter of Credit [Member] | DTE Gas [Member]
Short-term Debt [Line Items]
Other outstanding letters of credit	0
Demand Financing Agreement with Newedge plus letter of credit [Member] | DTE Energy [Member]
Short-term Debt [Line Items]
Financing Agreement, Maximum Borrowing Capacity	140
Demand Financing Agreement with Newedge [Member] | DTE Energy [Member]
Short-term Debt [Line Items]
Financing Agreement, Maximum Borrowing Capacity	100
Financing Agreement, Amount Outstanding	75	65
Maximum Additional Margin Financing	50
Other outstanding letters of credit [Member] | Letter of Credit [Member] | DTE Energy [Member]
Short-term Debt [Line Items]
Other outstanding letters of credit	47
Demand Financing Agreement with Newedge letter of credit to raise capacity [Member] | Letter of Credit [Member] | DTE Energy [Member]
Short-term Debt [Line Items]
Financing Agreement, Maximum Borrowing Capacity	$40

Commitments_and_Contingencies_1

Commitments and Contingencies (Details Textuals) (USD $)

9 Months Ended

9 Months Ended

9 Months Ended

9 Months Ended

12 Months Ended

Sep. 30, 2013

Aug. 31, 2013

Dec. 31, 2010

Sep. 30, 2013

Dec. 31, 2012

Aug. 31, 2012

Sep. 30, 2013

Dec. 31, 2012

Sep. 30, 2013

Sep. 30, 2013

Sep. 30, 2013

Dec. 31, 2011

dte_instances

Electric [Member]

Electric [Member]

Electric [Member]

Gas [Member]

Gas [Member]

Synthetic Fuel [Member]

Emissions [Member]

Other Guarantees [Member]

Eight Year [Member]

facilities

facilities

kWh

dte_instances

Loss Contingencies [Line Items]

Environmental Capital Expenditures Through Current Year

$1,900,000,000

Environmental Capital Expenditures in Current Year

190,000,000

Environmental Capital Expenditures In Future Years

1,800,000,000

EPA is Alleging Detroit Edison Power Plants Violated New Source Performance Standards

5

Number of NOVs/FOVs currently being discussed with the EPA

2

Sierra Club is Alleging DTE Electric Coal Fired Power Plants Violated the Clean Air Act

4

Exceedances of Opacity Standard

1,499

Period of excess opacity of air emissions at alleged facilities

6 minutes

2004 EPA proposed compliance timeline in years

8 years

Number of Former MGP Sites

3

15

Accrual for Environmental Loss Contingencies, Gross

9,000,000

9,000,000

29,000,000

29,000,000

Number of Options to Regulate Coal Ash Residue

2

Period Gas Utility Can Amortize MGP Costs

10 years

Number of NOVs

2

Possible Environmental Capital Expenditures to Comply with Requirements

7,000,000

EPA Sulfur Dioxide Ambient Air Quality Standard

1 hour

Waiting Period of Policy

P12W

Insurance Coverage for Extra ExpenseWhen to Necessitate Power Plant when Unavailable

490,000,000

Period of Coverage of Policy for Extra Expenses

3 years

Primary Coverage

500,000,000

Coverage for Stabilization Decontamination Debris Removal Repair and Replacement of Property and Decommissioning

2,250,000,000

Combined Coverage Limit for Total Property Damage

2,750,000,000

Insurance Deductible for Nuclear Power Plant

1,000,000

Total Limit for Property Damage for Non-Nuclear Events

1,800,000,000

Limit for Property Damage for Non-Nuclear Events Aggregate of Extra Expenses

327,000,000

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

34,000,000

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 Leviied Against Each Licensed Nuclear Facility

127,300,000

Limit Deferred Premium Charges Per Year

19,000,000

Company Obligated to Pay DOE Fee of Fermi 2 Electricity Generated and Sold

1

Settlement Provided for Delay-Related Costs

48,000,000

Days Obligations will Survive After Expiration of All Applicable Statutes of Limiations

90 days

90 days

Guarantor Obligations, Maximum Exposure, Undiscounted

1,200,000,000

125,000,000

60,000,000

Performance Bonds Outstanding

41,000,000

Long-term Purchase Commitment, Amount

6,200,000,000

Purchase Obligation, Future Minimum Payments, Remainder of Fiscal Year

2,100,000,000

Bankruptcy Claims, Accounts Receivable under Review by Management

$20,000,000

Retirement_Benefits_and_Truste2

Retirement Benefits and Trusteed Assets (Details) (USD $)	3 Months Ended		9 Months Ended
In Millions, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Pension Plan, Defined Benefit [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Service Cost	$22	$20	$71	$61
Interest Cost	49	51	144	153
Expected Return on Plan Assets	-67	-61	-200	-183
Amortization of Net Actuarial Losses	55	48	156	133
Amortization of Prior Service Cost (Credit)	0	0	0	0
Amortization of Net Transition Liability			0	0
Settlements			0	2
Net Periodic Benefit Cost	59	58	171	166
Other Postretirement Benefit Plan, Defined Benefit [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Service Cost	9	15	37	51
Interest Cost	21	29	66	90
Expected Return on Plan Assets	-28	-23	-82	-69
Amortization of Net Actuarial Losses	16	21	48	60
Amortization of Prior Service Cost (Credit)	-36	-6	-95	-20
Amortization of Net Transition Liability			0	1
Settlements			0	0
Net Periodic Benefit Cost	($18)	$36	($26)	$113

Retirement_Benefits_and_Truste3

Retirement Benefits and Trusteed Assets Retirement Benefits and Trusteed Assets (Details Textuals) (USD $)

9 Months Ended

3 Months Ended

9 Months Ended

3 Months Ended

9 Months Ended

3 Months Ended

9 Months Ended

Sep. 30, 2013

Jun. 30, 2013

Dec. 31, 2012

Sep. 30, 2013

Sep. 30, 2012

Sep. 30, 2013

Sep. 30, 2012

Jun. 30, 2013

Dec. 31, 2012

Sep. 30, 2013

Sep. 30, 2012

Sep. 30, 2013

Sep. 30, 2012

Sep. 30, 2013

Jun. 30, 2013

Mar. 31, 2013

Sep. 30, 2013

Other Postretirement Benefit Plan, Defined Benefit [Member]

Other Postretirement Benefit Plan, Defined Benefit [Member]

Other Postretirement Benefit Plan, Defined Benefit [Member]

Other Postretirement Benefit Plan, Defined Benefit [Member]

Other Postretirement Benefit Plan, Defined Benefit [Member]

Other Postretirement Benefit Plan, Defined Benefit [Member]

Pension Plan, Defined Benefit [Member]

Pension Plan, Defined Benefit [Member]

Pension Plan, Defined Benefit [Member]

Pension Plan, Defined Benefit [Member]

Common Stock [Member]

Common Stock [Member]

Common Stock [Member]

Common Stock [Member]

Pension Plan, Defined Benefit [Member]

Pension Plan, Defined Benefit [Member]

Pension Plan, Defined Benefit [Member]

Pension Plan, Defined Benefit [Member]

Defined Benefit Plans and Other Postretirement Benefit Plans [Line Items]

Service Cost

$9,000,000

$15,000,000

$37,000,000

$51,000,000

$22,000,000

$20,000,000

$71,000,000

$61,000,000

Pension Contributions

250,000,000

100,000,000

50,000,000

50,000,000

200,000,000

Estimated Future Employer Contributions in Current Fiscal Year

120,000,000

25,000,000

Contributions by Employer

145,000,000

Retiree Health Care Allowance

3,250

Assumptions Used Calculating Benefit Obligation, Discount Rate

4.30%

4.15%

Remeasurement Reduction to Post Retirement Benefit Obligation

258,000,000

439,000,000

Remeasurement Reduction to Post Retirement Benefit Obligation Liability

721,000,000

1,200,000,000

Remeasurement Decrease in Benefit Cost for Postretirement Plans

69,000,000

Annual Decrease in Other Postretirement Benefits Costs due to Remeasurement

$40,000,000

StockBased_Compensation_Detail

Stock-Based Compensation (Details) (USD $)	3 Months Ended		9 Months Ended
In Millions, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock-based compensation expense	$18	$21	$81	$61
Tax benefit	7	8	31	23
Stock-based compensation cost capitalized in property, plant and equipment	$1	$1	$5	$3

StockBased_Compensation_Detail1

Stock-Based Compensation (Details 1) (USD $)	9 Months Ended
In Millions, except Share data, unless otherwise specified	Sep. 30, 2013
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Options outstanding	1,192,670
Exercised	399,139
Forfeitured or expired	10,370
Options outstanding	783,161
Options exercisable	783,161
Weighted Average Exercise Price Per Share - Options outstanding	$41.86
Weighted Average Exercise Price Per Share - Exercised	$40.54
Weighted Average Exercise Price Per Share - Forfeitured or expired	$41.46
Weighted Average Exercise Price Per Share - Options outstanding	$42.54
Weighted Average Exercise Price Per Share - Options exercisable	$42.54
Aggregate Intrinsic Value - Options outstanding	$20
Aggregate Intrinsic Value - Options exercisable	$20

StockBased_Compensation_StockB

Stock-Based Compensation Stock-Based Compensation (Details 2) (USD $)	9 Months Ended
	Sep. 30, 2013
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Restricted Stock Award Activity Forfeitures	-10,370
Restricted Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Number	597,648
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period	127,785
Restricted Stock Award Activity Forfeitures	-5,621
Restricted Stock Award Activity Vested and Issued	-218,600
Share-based Compensation Arrangement by Share-based Payment Award, Non-Option Equity Instruments, Outstanding, Number	501,212
Weighted Average Grant Date Fair Value Per Share Balance	48.33
Weighted Average Grant Date Fair Value, Grants	64.72
Weighted Average Grant Date Fair Value, Forfeitures	53.53
Weighted Average Fair Value Per Share, Vested and issued	45.39
Weighted Average Grant Date Fair Value Per Share Balance	53.71
Performance Shares [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Number	1,634,364
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period	549,360
Restricted Stock Award Activity Forfeitures	-36,168
Share Based Compensation Arrangements Other than options payout in period	-548,624
Share-based Compensation Arrangement by Share-based Payment Award, Non-Option Equity Instruments, Outstanding, Number	1,598,932

StockBased_Compensation_Detail2

Stock-Based Compensation (Details Textuals) (USD $)	9 Months Ended
In Millions, except Share data, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012
Share-based Compensation [Abstract]
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Weighted Average Remaining Contractual Term	4 years 2 months 2 days
Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested and Expected to Vest, Exercisable, Number	200,844
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period, Total Intrinsic Value	$11	$21
Stock or Unit Option Plan Expense	0	0.5
Unrecognized Compensation Cost	$72
Weighted Average to be Recognized	1 year 2 months 6 days

Segment_Information_Details

Segment Information (Details) (USD $)	3 Months Ended		9 Months Ended
In Millions, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Segment Reporting, Revenue Reconciling Item [Line Items]
Operating Revenues	$2,387	$2,190	$7,128	$6,442
Operating Segments [Member] | Electric [Member]
Segment Reporting, Revenue Reconciling Item [Line Items]
Operating Revenues	1,458	1,543	3,942	4,031
Operating Segments [Member] | Gas [Member]
Segment Reporting, Revenue Reconciling Item [Line Items]
Operating Revenues	161	160	1,013	883
Operating Segments [Member] | Gas Storage and Pipelines [Member]
Segment Reporting, Revenue Reconciling Item [Line Items]
Operating Revenues	34	21	92	73
Operating Segments [Member] | Power and Industrial Projects [Member]
Segment Reporting, Revenue Reconciling Item [Line Items]
Operating Revenues	512	477	1,431	1,375
Operating Segments [Member] | Energy Trading [Member]
Segment Reporting, Revenue Reconciling Item [Line Items]
Operating Revenues	463	223	1,307	723
Operating Segments [Member] | Corporate and Other [Member]
Segment Reporting, Revenue Reconciling Item [Line Items]
Operating Revenues	1	0	2	2
Intersegment Eliminations [Member]
Segment Reporting, Revenue Reconciling Item [Line Items]
Inter-segment Revenues	242	234	659	645
Intersegment Eliminations [Member] | Electric [Member]
Segment Reporting, Revenue Reconciling Item [Line Items]
Inter-segment Revenues	6	7	19	22
Intersegment Eliminations [Member] | Gas [Member]
Segment Reporting, Revenue Reconciling Item [Line Items]
Inter-segment Revenues	2	1	4	3
Intersegment Eliminations [Member] | Gas Storage and Pipelines [Member]
Segment Reporting, Revenue Reconciling Item [Line Items]
Inter-segment Revenues	-2	1	2	5
Intersegment Eliminations [Member] | Power and Industrial Projects [Member]
Segment Reporting, Revenue Reconciling Item [Line Items]
Inter-segment Revenues	231	225	621	608
Intersegment Eliminations [Member] | Energy Trading [Member]
Segment Reporting, Revenue Reconciling Item [Line Items]
Inter-segment Revenues	13	10	36	34
Intersegment Eliminations [Member] | Corporate and Other [Member]
Segment Reporting, Revenue Reconciling Item [Line Items]
Inter-segment Revenues	-8	-11	-23	-28
Intersegment Eliminations [Member] | Discontinued Operations [Member]
Segment Reporting, Revenue Reconciling Item [Line Items]
Inter-segment Revenues	$0	$1	$0	$1

Segment_Information_Details_1

Segment Information (Details 1) (USD $)	3 Months Ended		9 Months Ended
In Millions, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Net Income (Loss) Attributable to Parent	$198	$227	$537	$529
Electric [Member]
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Net Income (Loss) Attributable to Parent	179	194	383	417
Gas [Member]
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Net Income (Loss) Attributable to Parent	-13	4	91	60
Gas Storage and Pipelines [Member]
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Net Income (Loss) Attributable to Parent	16	14	49	48
Power and Industrial Projects [Member]
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Net Income (Loss) Attributable to Parent	27	22	46	40
Energy Trading [Member]
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Net Income (Loss) Attributable to Parent	-6	1	-1	3
Corporate and Other [Member]
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Net Income (Loss) Attributable to Parent	-5	-9	-31	-39
Discontinued Operations [Member]
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Net Income (Loss) Attributable to Parent	$0	$1	$0	$0

Segment_Information_Details_Te

Segment Information (Details Textuals)	Sep. 30, 2013
	customers
Entity Information [Line Items]
Number of Electric Customers	2,100,000
Number of Gas Customers	1,200,000
Number of Citizens Gas Customers	17,000