Document and Entity Information Document and Entity Information - USD ($) $ in Billions	12 Months Ended
	Dec. 31, 2019	Jan. 24, 2020	Jun. 28, 2019
Entity Information [Line Items]
Document Type	10-K
Document Annual Report	true
Document Period End Date	Dec. 31, 2019
Document Transition Report	false
Entity File Number	1-11607
Entity Registrant Name	DTE Energy Co
Entity Incorporation, State or Country Code	MI
Entity Tax Identification Number	38-3217752
Entity Address, Address Line One	One Energy Plaza
Entity Address, City or Town	Detroit
Entity Address, State or Province	MI
Entity Address, Postal Zip Code	48226-1279
City Area Code	313
Local Phone Number	235-4000
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Public Float			$ 23.1
Entity Common Stock, Shares Outstanding		192,234,700
Documents Incorporated by Reference	Certain information in DTE Energy's definitive Proxy Statement for its 2020 Annual Meeting of Common Shareholders to be held May 7, 2020, which will be filed with the Securities and Exchange Commission pursuant to Regulation 14A, not later than 120 days after the end of the registrant’s fiscal year covered by this report on Form 10-K, is incorporated herein by reference to Part III (Items 10, 11, 12, 13, and 14) of this Form 10-K. This combined Form 10-K is filed separately by two registrants: DTE Energy and DTE Electric. Information contained herein relating to any individual registrant is filed by such registrant solely on its own behalf. DTE Electric makes no representation as to information relating exclusively to DTE Energy. DTE Electric, a wholly-owned subsidiary of DTE Energy, meets the conditions set forth in General Instructions I(1)(a) and (b) of Form 10-K and is therefore filing this form with the reduced disclosure format specified in General Instruction I(2) of Form 10-K.
Entity Central Index Key	0000936340
Current Fiscal Year End Date	--12-31
Document Fiscal Year Focus	2019
Document Fiscal Period Focus	FY
Amendment Flag	false
Common stock, without par value
Entity Information [Line Items]
Title of 12(b) Security	Common stock, without par value
Trading Symbol	DTE
Security Exchange Name	NYSE
2012 Series C 5.25% Junior Subordinated Debentures due 2062
Entity Information [Line Items]
Title of 12(b) Security	2012 Series C 5.25% Junior Subordinated Debentures due 2062
Trading Symbol	DTQ
Security Exchange Name	NYSE
2016 Series B 5.375% Junior Subordinated Debentures due 2076
Entity Information [Line Items]
Title of 12(b) Security	2016 Series B 5.375% Junior Subordinated Debentures due 2076
Trading Symbol	DTJ
Security Exchange Name	NYSE
2016 Series F 6.00% Junior Subordinated Debentures due 2076
Entity Information [Line Items]
Title of 12(b) Security	2016 Series F 6.00% Junior Subordinated Debentures due 2076
Trading Symbol	DTY
Security Exchange Name	NYSE
2017 Series E 5.25% Junior Subordinated Debentures due 2077
Entity Information [Line Items]
Title of 12(b) Security	2017 Series E 5.25% Junior Subordinated Debentures due 2077
Trading Symbol	DTW
Security Exchange Name	NYSE
2019 6.25% Corporate Units
Entity Information [Line Items]
Title of 12(b) Security	2019 6.25% Corporate Units
Trading Symbol	DTP
Security Exchange Name	NYSE
DTE Electric
Entity Information [Line Items]
Entity File Number	1-2198
Entity Registrant Name	DTE Electric Co
Entity Incorporation, State or Country Code	MI
Entity Tax Identification Number	38-0478650
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Non-accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		138,632,324
Entity Central Index Key	0000028385

Consolidated Statements of Operations - USD ($) shares in Millions, $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Operating Revenues
Utility operations	$ 6,638	$ 6,670	$ 6,434
Non-utility operations	6,031	7,542	6,173
Operating Revenues	12,669	14,212	12,607
Operating Expenses
Fuel, purchased power, and gas — utility	1,798	1,981	1,881
Fuel, purchased power, and gas — non-utility	5,053	6,630	5,283
Operation and maintenance	2,419	2,451	2,270
Depreciation and amortization	1,263	1,124	1,030
Taxes other than income	414	405	391
Asset (gains) losses and impairments, net	15	27	41
Operating Expenses	10,962	12,618	10,896
Operating Income	1,707	1,594	1,711
Other (Income) and Deductions
Interest expense	641	559	536
Interest income	(17)	(12)	(12)
Non-operating retirement benefits, net	39	37	65
Other income	(350)	(333)	(268)
Other expenses	70	127	103
Other (Income) and Deductions	383	378	424
Income Before Income Taxes	1,324	1,216	1,287
Income Tax Expense	152	98	175
Net Income	1,172	1,118	1,112
Less: Net Income (Loss) Attributable to Noncontrolling Interests	3	(2)	(22)
Net Income Attributable to DTE Energy Company/DTE Electric Company	$ 1,169	$ 1,120	$ 1,134
Basic Earnings per Common Share
Net income attributable to DTE Energy Company (in dollars per share)	$ 6.32	$ 6.18	$ 6.32
Diluted Earnings per Common Share
Net income attributable to DTE Energy Company (in dollars per share)	$ 6.31	$ 6.17	$ 6.32
Weighted Average Common Shares Outstanding
Basic (in shares)	185	181	179
Diluted (in shares)	185	181	179
DTE Electric
Operating Revenues
Utility operations	$ 5,224	$ 5,298	$ 5,102
Operating Revenues	5,224	5,298
Operating Expenses
Fuel, purchased power, and gas — utility	1,390	1,552	1,454
Operation and maintenance	1,452	1,470	1,428
Depreciation and amortization	946	836	753
Taxes other than income	310	307	302
Asset (gains) losses and impairments, net	13	(1)	0
Operating Expenses	4,111	4,164	3,937
Operating Income	1,113	1,134	1,165
Other (Income) and Deductions
Interest expense	313	283	274
Interest income	(2)	0	0
Non-operating retirement benefits, net	(1)	0	0
Other income	(107)	(83)	(77)
Other expenses	56	77	40
Other (Income) and Deductions	259	277	237
Income Before Income Taxes	854	857	928
Income Tax Expense	138	193	327
Net Income Attributable to DTE Energy Company/DTE Electric Company	$ 716	$ 664	$ 601

Consolidated Statements of Comprehensive Income - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Net Income	$ 1,172	$ 1,118	$ 1,112
Net Income	1,169	1,120	1,134
Other comprehensive income (loss), net of tax:
Benefit obligations, net of taxes	8	8	10
Net unrealized gains (losses) on derivatives during the period, net of taxes	(12)
Net unrealized gains (losses) on derivatives during the period, net of taxes		(1)	1
Net unrealized gains on investments during the period, net of taxes	0	0	1
Foreign currency translation	1	(2)	1
Other comprehensive income (loss)	(3)	5	13
Comprehensive income	1,169	1,123	1,125
Less: Comprehensive income (loss) attributable to noncontrolling interests	3	(2)	(22)
Comprehensive Income Attributable to DTE Energy Company/DTE Electric Company	1,166	1,125	1,147
DTE Electric
Net Income	716	664	601
Other comprehensive income (loss), net of tax:
Net unrealized gains on investments during the period, net of taxes	0	0	1
Other comprehensive income (loss)	0	0	1
Comprehensive Income Attributable to DTE Energy Company/DTE Electric Company	$ 716	$ 664	$ 602

Consolidated Statements of Comprehensive Income (Parenthetical) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Tax effect on benefit obligation	$ 2	$ 2	$ 5
Tax effect on net unrealized gains (losses) on derivatives during the period	(4)
Tax effect on net unrealized gains (losses) on derivatives during the period		0	0
Tax effect on net unrealized gains (losses) on investments during the period	0	0	1
DTE Electric
Tax effect on net unrealized gains (losses) on investments during the period	$ 0	$ 0	$ 1

Consolidated Statements of Financial Position - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018
Current Assets
Cash and cash equivalents	$ 93	$ 71
Restricted cash	0	5
Accounts receivable (less allowance for doubtful accounts)
Customer	1,642	1,789
Other	245	108
Inventories
Fuel and gas	373	406
Materials and supplies	386	405
Derivative assets	133	102
Regulatory assets	5	153
Other	209	221
Total Current Assets	3,086	3,260
Investments
Nuclear decommissioning trust funds	1,661	1,378
Investments in equity method investees	1,862	1,771
Other	265	219
Total Investments	3,788	3,368
Property
Property, plant, and equipment	35,072	31,810
Accumulated depreciation and amortization	(9,755)	(10,160)
Property, plant and equipment, net	25,317	21,650
Other Assets
Goodwill	2,464	2,293
Regulatory assets	4,171	4,568
Intangible assets	2,393	849
Notes receivable	202	64
Derivative assets	41	31
Prepaid postretirement costs	69	45
Operating lease right-of-use assets	169
Other	182	160
Total Other Assets	9,691	8,010
Total Assets	41,882	36,288
Current Liabilities
Accounts payable	1,076	1,329
Accounts payable
Accrued interest	147	127
Dividends payable	195	172
Short-term borrowings	828	609
Current portion long-term debt, including finance leases	687	1,499
Derivative liabilities	83	67
Regulatory liabilities	65	126
Short-term borrowings
Operating lease liabilities	33
Acquisition related deferred payment	379	0
Other	504	509
Total Current Liabilities	3,997	4,438
Long-Term Debt (net of current portion)
Mortgage bonds, notes, and other	14,778	10,982
Junior subordinated debentures	1,146	1,145
Finance lease obligations	11
Finance lease obligations		7
Total Long-Term Debt (net of current portion)	15,935	12,134
Other Liabilities
Deferred income taxes	2,315	1,975
Regulatory liabilities	3,264	2,922
Asset retirement obligations	2,672	2,469
Unamortized investment tax credit	166	138
Derivative liabilities	86	89
Accrued pension liability	808	837
Nuclear decommissioning	249	205
Operating lease liability	127
Other	427	364
Total Other Liabilities	10,114	8,999
Commitments and Contingencies (Notes 10 and 19)
Equity
Common stock	5,233	4,245
Retained earnings	6,587	6,112
Accumulated other comprehensive loss	(148)	(120)
Total DTE Energy Company/DTE Electric Company Equity	11,672	10,237
Noncontrolling interests	164	480
Total Equity	11,836	10,717
Total Liabilities and Equity	41,882	36,288
DTE Electric
Current Assets
Cash and cash equivalents	12	18
Accounts receivable (less allowance for doubtful accounts)
Customer	729	750
Affiliates	25	11
Other	41	54
Inventories
Fuel and gas	187	171
Materials and supplies	280	279
Regulatory assets	5	148
Other	78	89
Total Current Assets	1,357	1,520
Investments
Nuclear decommissioning trust funds	1,661	1,378
Other	38	34
Total Investments	1,699	1,412
Property
Property, plant, and equipment	24,279	22,747
Accumulated depreciation and amortization	(6,706)	(7,310)
Property, plant and equipment, net	17,573	15,437
Other Assets
Regulatory assets	3,448	3,829
Intangible assets	15	21
Prepaid postretirement costs — affiliates	266	189
Operating lease right-of-use assets	87
Other	143	121
Total Other Assets	3,959	4,160
Total Assets	24,588	22,529
Accounts payable
Affiliates	59	71
Other	406	441
Accrued interest	84	74
Current portion long-term debt, including finance leases	636	4
Regulatory liabilities	40	98
Short-term borrowings
Affiliates	97	101
Other	354	149
Operating lease liabilities	12
Other	155	139
Total Current Liabilities	1,843	1,077
Long-Term Debt (net of current portion)
Mortgage bonds, notes, and other	6,548	6,538
Finance lease obligations	4
Finance lease obligations		7
Total Long-Term Debt (net of current portion)	6,552	6,545
Other Liabilities
Deferred income taxes	2,355	2,246
Regulatory liabilities	2,546	2,171
Asset retirement obligations	2,447	2,271
Unamortized investment tax credit	166	137
Nuclear decommissioning	249	205
Accrued pension liability — affiliates	717	718
Accrued postretirement liability — affiliates	367	278
Operating lease liability	67
Other	84	88
Total Other Liabilities	8,998	8,114
Commitments and Contingencies (Notes 10 and 19)
Equity
Common stock	4,811	4,631
Retained earnings	2,384	2,162
Total DTE Energy Company/DTE Electric Company Equity	7,195	6,793
Total Liabilities and Equity	$ 24,588	$ 22,529

Consolidated Statements of Financial Position (Parenthetical) - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018
Current Assets:
Allowance for doubtful accounts	$ 91	$ 91
Stockholders' Equity:
Common stock, shares authorized (in shares)	400,000,000	400,000,000
Common stock, shares issued (in shares)	192,208,533	181,925,281
Common stock, shares outstanding (in shares)	192,208,533	181,925,281
DTE Electric
Current Assets:
Allowance for doubtful accounts	$ 46	$ 53
Stockholders' Equity:
Common stock, par value (in dollars per share)	$ 10	$ 10
Common stock, shares authorized (in shares)	400,000,000	400,000,000
Common stock, shares issued (in shares)	138,632,324	138,632,324
Common stock, shares outstanding (in shares)	138,632,324	138,632,324

Consolidated Statements of Cash Flows - USD ($)
$ in Millions

12 Months Ended

Dec. 31, 2019

Dec. 31, 2018

Dec. 31, 2017

Operating Activities

Net Income

$ 1,172

$ 1,118

$ 1,112

Net Income

1,169

1,120

1,134

Adjustments to reconcile Net Income to Net cash from operating activities:

Depreciation and amortization

1,263

1,124

1,030

Nuclear fuel amortization

60

45

53

Allowance for equity funds used during construction

(24)

(28)

(23)

Deferred income taxes

329

114

196

Equity earnings of equity method investees

(111)

(132)

(102)

Dividends from equity method investees

160

74

Asset (gains) losses and impairments, net

14

29

38

Changes in assets and liabilities:

Accounts receivable, net

49

(44)

(252)

Inventories

59

(32)

(4)

Prepaid postretirement benefit costs

(24)

(45)

0

Accounts payable

(288)

146

129

Accrued pension liability

(29)

(87)

(228)

Accrued postretirement liability

0

(61)

25

Derivative assets and liabilities

(28)

31

(94)

Regulatory assets and liabilities

160

15

217

Other current and noncurrent assets and liabilities

(113)

413

(54)

Net cash from operating activities

2,649

2,680

2,117

Investing Activities

Plant and equipment expenditures — utility

(2,724)

(2,439)

(2,037)

Plant and equipment expenditures — non-utility

(273)

(274)

(213)

Acquisition, net of cash acquired

(2,470)

0

Proceeds from sale of nuclear decommissioning trust fund assets

788

1,203

1,240

Investment in nuclear decommissioning trust funds

(794)

(1,188)

(1,226)

Distributions from equity method investees

10

9

10

Contributions to equity method investees

(149)

(637)

(299)

Notes receivable

(98)

Notes receivable

2

1

Other

(22)

(23)

(38)

Net cash used for investing activities

(5,732)

(3,347)

(2,562)

Financing Activities

Issuance of long-term debt, net of issuance costs

2,506

1,432

1,398

Redemption of long-term debt

(821)

(105)

(385)

Issuance of equity units, net of issuance costs

1,265

0

Short-term borrowings, net

219

122

Short-term borrowings, net

(12)

Issuance of common stock

1,023

0

Repurchase of common stock

0

(51)

Dividends on common stock

(692)

(620)

(592)

Contributions from noncontrolling interests, principally REF entities

38

53

50

Distributions to noncontrolling interests

(59)

(48)

(40)

Purchases of noncontrolling interest, principally SGG

(300)

0

Other

(79)

(46)

(81)

Net cash from (used for) financing activities

3,100

654

421

Net Increase (Decrease) in Cash, Cash Equivalents, and Restricted Cash

17

(13)

(24)

Cash, Cash Equivalents, and Restricted Cash at Beginning of Period

76

89

113

Cash, Cash Equivalents, and Restricted Cash at End of Period

93

76

89

Supplemental disclosure of cash information

Cash paid (received) for: Interest, net of interest capitalized

595

572

495

Cash paid (received) for: Income taxes

18

(26)

4

Supplemental disclosure of non-cash investing and financing activities

Plant and equipment expenditures in accounts payable

^[1]

311

307

295

Premium on equity units

^[1]

150

0

DTE Electric

Operating Activities

Net Income

716

664

601

Adjustments to reconcile Net Income to Net cash from operating activities:

Depreciation and amortization

946

836

753

Nuclear fuel amortization

60

45

53

Allowance for equity funds used during construction

(22)

(19)

(18)

Deferred income taxes

97

189

345

Asset (gains) losses and impairments, net

13

0

Changes in assets and liabilities:

Accounts receivable, net

20

33

(80)

Inventories

(17)

15

31

Prepaid postretirement benefit costs — affiliates

(77)

(76)

1

Accounts payable

(57)

54

(2)

Accrued pension liability — affiliates

(1)

(93)

(197)

Accrued postretirement liability — affiliates

89

(33)

42

Regulatory assets and liabilities

139

4

202

Other current and noncurrent assets and liabilities

(197)

101

(147)

Net cash from operating activities

1,709

1,720

1,584

Investing Activities

Plant and equipment expenditures

(2,200)

(1,989)

(1,574)

Proceeds from sale of nuclear decommissioning trust fund assets

788

1,203

1,240

Investment in nuclear decommissioning trust funds

(794)

(1,188)

(1,226)

Other

(21)

(15)

18

Net cash used for investing activities

(2,227)

(1,989)

(1,542)

Financing Activities

Issuance of long-term debt, net of issuance costs

643

519

435

Redemption of long-term debt

0

(300)

Capital contribution by parent company

180

325

100

Short-term borrowings, net — affiliate

(4)

(15)

(1)

Short-term borrowings, net — other

205

(89)

176

Dividends on common stock

(494)

(461)

(432)

Other

(18)

(7)

(18)

Net cash from (used for) financing activities

512

272

(40)

Net Increase (Decrease) in Cash, Cash Equivalents, and Restricted Cash

(6)

3

2

Cash, Cash Equivalents, and Restricted Cash at Beginning of Period

18

15

13

Cash, Cash Equivalents, and Restricted Cash at End of Period

12

18

15

Supplemental disclosure of cash information

Cash paid (received) for: Interest, net of interest capitalized

295

283

252

Cash paid (received) for: Income taxes

46

0

(16)

Supplemental disclosure of non-cash investing and financing activities

Plant and equipment expenditures in accounts payable

$ 192

$ 181

$ 191

[1]	See Note 15 to the Consolidated Financial Statements, "Long-Term Debt" for additional non-cash financing activity related to the remarketing of RSNs.

Consolidated Statements of Changes in Equity - USD ($) $ in Millions	Total	Common Stock	Retained Earnings	Accumulated Other Comprehensive Income (Loss)	Noncontrolling Interests	DTE Electric	DTE Electric Common Stock	DTE Electric Additional Paid-in Capital	DTE Electric Retained Earnings	DTE Electric Accumulated Other Comprehensive Income (Loss)
Beginning balance (in shares) at Dec. 31, 2016		179,433,000					138,632,000
Beginning balance at Dec. 31, 2016	$ 9,499	$ 4,030	$ 5,114	$ (133)	$ 488
Beginning balance at Dec. 31, 2016						$ 5,995	$ 1,386	$ 2,820	$ 1,787	$ 2
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net Income (Loss)	1,112		1,134		(22)
Net Income	1,134					601			601
Dividends declared on common stock	(602)		(602)			(432)			(432)
Repurchase of common stock (in shares)		(524,000)
Repurchase of common stock	(51)	$ (51)
Other comprehensive income (loss), net of tax	13			13		1				1
Stock-based compensation, net contributions from (distributions to) noncontrolling interests, and other (in shares)		478,000
Stock-based compensation, net contributions from (distributions to) noncontrolling interests, and other	19	$ 10	(3)		12
Capital contribution by parent company						100		100
Ending balance (in shares) at Dec. 31, 2017		179,387,000					138,632,000
Ending balance at Dec. 31, 2017	9,990	$ 3,989	5,643	(120)	478
Ending balance at Dec. 31, 2017						6,265	$ 1,386	2,920	1,956	3
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net Income (Loss)	1,118		1,120		(2)
Net Income	1,120					664			664
Dividends declared on common stock	(653)		(653)			(461)			(461)
Issuance of common stock (in shares)		255,000
Issuance of common stock	26	$ 26
Contribution of common stock to pension plan (in shares)		1,751,000
Contribution of common stock to pension plan	175	$ 175
Other comprehensive income (loss), net of tax	5			5		0
Stock-based compensation, net contributions from (distributions to) noncontrolling interests, and other (in shares)		532,000
Stock-based compensation, net contributions from (distributions to) noncontrolling interests, and other	$ 56	$ 55	(3)		4
Capital contribution by parent company						$ 325		325
Ending balance (in shares) at Dec. 31, 2018	181,925,281	181,925,000				138,632,324	138,632,000
Ending balance at Dec. 31, 2018	$ 10,717	$ 4,245	6,112	(120)	480
Ending balance at Dec. 31, 2018	10,237					$ 6,793	$ 1,386	3,245	2,162	0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net Income (Loss)	1,172		1,169		3
Net Income	1,169					716			716
Dividends declared on common stock	(714)		(714)			(494)			(494)
Issuance of common stock (in shares)		8,634,000
Issuance of common stock	1,014	$ 1,014
Premium on equity units	(150)	(150)
Issuance costs of equity units	(30)	$ (30)
Contribution of common stock to pension plan (in shares)		815,000
Contribution of common stock to pension plan	100	$ 100
Other comprehensive income (loss), net of tax	(3)			(3)		0
Purchase of noncontrolling interests, principally SGG	(300)	$ (3)			(297)
Stock-based compensation, net contributions from (distributions to) noncontrolling interests, and other (in shares)		835,000
Stock-based compensation, net contributions from (distributions to) noncontrolling interests, and other	$ 30	$ 57	(5)		(22)
Capital contribution by parent company						$ 180		180
Ending balance (in shares) at Dec. 31, 2019	192,208,533	192,209,000				138,632,324	138,632,000
Ending balance at Dec. 31, 2019	$ 11,836	$ 5,233	$ 6,587	$ (148)	$ 164
Ending balance at Dec. 31, 2019	$ 11,672					$ 7,195	$ 1,386	$ 3,425	$ 2,384	$ 0

Consolidated Statements of Changes in Equity (Parenthetical) - $ / shares	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Statement of Stockholders' Equity [Abstract]
Dividends declared on common stock (in dollars per share)	$ 3.85	$ 3.60	$ 3.36

Organization and Basis of Presentation

12 Months Ended

Dec. 31, 2019

Organization, Consolidation and Presentation of Financial Statements [Abstract]

Organization and Basis of Presentation

ORGANIZATION AND BASIS OF PRESENTATION

Corporate Structure

DTE Energy owns the following businesses:


•	DTE Electric is a public utility engaged in the generation, purchase, distribution, and sale of electricity to approximately 2.2 million customers in southeastern Michigan;


•	DTE Gas is a public utility engaged in the purchase, storage, transportation, distribution, and sale of natural gas to approximately 1.3 million customers throughout Michigan and the sale of storage and transportation capacity; and


•	Other businesses primarily involved in 1) services related to the gathering, transportation, and storage of natural gas; 2) power and industrial projects; and 3) energy marketing and trading operations.

DTE Electric and DTE Gas are regulated by the MPSC. Certain activities of DTE Electric and DTE Gas, as well as various other aspects of businesses under DTE Energy are regulated by the FERC. In addition, the Registrants are regulated by other federal and state regulatory agencies including the NRC, the EPA, the EGLE, and for DTE Energy, the CFTC.

Basis of Presentation

The accompanying Consolidated Financial Statements of the Registrants are prepared using accounting principles generally accepted in the United States of America. These accounting principles require management to use estimates and assumptions that impact reported amounts of assets, liabilities, revenues and expenses, and the disclosure of contingent assets and liabilities. Actual results may differ from the Registrants' estimates.

The information in these combined notes relates to each of the Registrants as noted in the Index of Combined Notes to Consolidated Financial Statements. However, DTE Electric does not make any representation as to information related solely to DTE Energy or the subsidiaries of DTE Energy other than itself.

Certain prior year balances for the Registrants were reclassified to match the current year's Consolidated Financial Statements presentation.

Principles of Consolidation

The Registrants consolidate all majority-owned subsidiaries and investments in entities in which they have controlling influence. Non-majority owned investments are accounted for using the equity method when the Registrants are able to significantly influence the operating policies of the investee. When the Registrants do not influence the operating policies of an investee, the cost method is used. These Consolidated Financial Statements also reflect the Registrants' proportionate interests in certain jointly-owned utility plants. The Registrants eliminate all intercompany balances and transactions.

The Registrants evaluate whether an entity is a VIE whenever reconsideration events occur. The Registrants consolidate VIEs for which they are the primary beneficiary. If a Registrant is not the primary beneficiary and an ownership interest is held, the VIE is accounted for under the equity method of accounting. When assessing the determination of the primary beneficiary, a Registrant considers all relevant facts and circumstances, including: the power, through voting or similar rights, to direct the activities of the VIE that most significantly impact the VIE's economic performance and the obligation to absorb the expected losses and/or the right to receive the expected returns of the VIE. The Registrants perform ongoing reassessments of all VIEs to determine if the primary beneficiary status has changed.

Legal entities within DTE Energy's Power and Industrial Projects segment enter into long-term contractual arrangements with customers to supply energy-related products or services. The entities are generally designed to pass-through the commodity risk associated with these contracts to the customers, with DTE Energy retaining operational and customer default risk. These entities generally are VIEs and consolidated when DTE Energy is the primary beneficiary. In addition, DTE Energy has interests in certain VIEs through which control of all significant activities is shared with partners, and therefore are generally accounted for under the equity method.

DTE Energy currently owns an 85% interest in SGG, which owns and operates midstream natural gas assets. SGG has contracts through which certain construction risk is designed to pass-through to the customers, with DTE Energy retaining operational and customer default risk. SGG is a VIE with DTE Energy as the primary beneficiary.

The Registrants have variable interests in NEXUS, which include DTE Energy's 50% ownership interest and DTE Electric's transportation services contract. NEXUS is a joint venture which owns a 256-mile pipeline to transport Utica and Marcellus shale gas to Ohio, Michigan, and Ontario market centers. NEXUS also owns Generation Pipeline, LLC, a 23-mile regulated pipeline system located in northern Ohio, which was acquired in September 2019. Refer to Note 4, "Acquisitions," for additional information. NEXUS is a VIE as it has insufficient equity at risk to finance its activities. The Registrants are not the primary beneficiaries, as the power to direct significant activities is shared between the owners of the equity interests. DTE Energy accounts for its ownership interest in NEXUS under the equity method.

The Registrants hold ownership interests in certain limited partnerships. The limited partnerships include investment funds which support regional development and economic growth, as well as an operational business providing energy-related products. These entities are generally VIEs as a result of certain characteristics of the limited partnership voting rights. The ownership interests are accounted for under the equity method as the Registrants are not the primary beneficiaries.

DTE Energy has variable interests in VIEs through certain of its long-term purchase and sale contracts. DTE Electric has variable interests in VIEs through certain of its long-term purchase contracts. As of December 31, 2019, the carrying amount of assets and liabilities in DTE Energy's Consolidated Statements of Financial Position that relate to its variable interests under long-term purchase and sale contracts are predominantly related to working capital accounts and generally represent the amounts owed by or to DTE Energy for the deliveries associated with the current billing cycle under the contracts. As of December 31, 2019, the carrying amount of assets and liabilities in DTE Electric's Consolidated Statements of Financial Position that relate to its variable interests under long-term purchase contracts are predominantly related to working capital accounts and generally represent the amounts owed by DTE Electric for the deliveries associated with the current billing cycle under the contracts. The Registrants have not provided any significant form of financial support associated with these long-term contracts. There is no material potential exposure to loss as a result of DTE Energy's variable interests through these long-term purchase and sale contracts. In addition, there is no material potential exposure to loss as a result of DTE Electric's variable interests through these long-term purchase contracts.

The maximum risk exposure for consolidated VIEs is reflected on the Registrants' Consolidated Statements of Financial Position and for DTE Energy, in Note 19 to the Consolidated Financial Statements, "Commitments and Contingencies," related to the REF guarantees and indemnities. For non-consolidated VIEs, the maximum risk exposure of the Registrants is generally limited to their investment, notes receivable, future funding commitments, and amounts which DTE Energy has guaranteed. See Note 19 to the Consolidated Financial Statements, "Commitments and Contingencies," for further discussion of the NEXUS guarantee arrangements.

The following table summarizes the major Consolidated Statements of Financial Position items for consolidated VIEs as of December 31, 2019 and 2018. 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 DTE Energy holds a majority voting interest and is the primary beneficiary, that meet the definition of a business and whose assets can be used for purposes other than the settlement of the VIE's obligations have been excluded from the table below.

Amounts for DTE Energy's consolidated VIEs are as follows:



	December 31, 2019						December 31, 2018
	SGG^(a)		Other		Total		SGG^(a)		Other		Total
	(In millions)
ASSETS
Cash and cash equivalents	$	16	$	11	$	27	$	25	$	14	$	39
Restricted cash	—		—		—		—		5		5
Accounts receivable	8		19		27		9		37		46
Inventories	—		74		74		1		92		93
Property, plant, and equipment, net	410		33		443		395		46		441
Goodwill	25		—		25		25		—		25
Intangible assets	542		—		542		557		—		557
Other current and long-term assets	2		—		2		3		—		3
	$	1,003	$	137	$	1,140	$	1,015	$	194	$	1,209

LIABILITIES
Accounts payable and accrued current liabilities	$	2	$	13	$	15	$	3	$	31	$	34
Other current and long-term liabilities	7		7		14		9		10		19
	$	9	$	20	$	29	$	12	$	41	$	53

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(a)	Amounts shown are 100% of SGG's assets and liabilities, of which DTE Energy owns 85% at December 31, 2019 and 55% at December 31, 2018.

Amounts for DTE Energy's non-consolidated VIEs are as follows:



	December 31,
	2019		2018
	(In millions)
Investments in equity method investees	$	1,503	$	1,425
Notes receivable	$	21	$	15
Future funding commitments	$	63	$	55

Equity Method Investments

Investments in non-consolidated affiliates that are not controlled by the Registrants, but over which they have significant influence, are accounted for using the equity method. Certain of the equity method investees are also considered VIEs and disclosed in the non-consolidated VIEs table above. At December 31, 2019 and 2018, DTE Energy's share of the underlying equity in the net assets of the investees exceeded the carrying amounts of Investments in equity method investees by $74 million and $59 million, respectively. The difference is being amortized over the life of the underlying assets.

DTE Energy equity method investees are described below:



	Investments				% Owned
Segment	2019		2018		2019	2018	Description
	(In millions)
Significant Equity Method Investees
Gas Storage and Pipelines
NEXUS Pipeline	$	1,345	$	1,260	50%	50%	256-mile pipeline to transport Utica and Marcellus shale gas to Ohio, Michigan, and Ontario market centers. Also includes Generation Pipeline, a 23-mile pipeline located in northern Ohio
Vector Pipeline	131		123		40%	40%	348-mile pipeline connecting Chicago, Michigan, and Ontario market centers
Millennium Pipeline	209		202		26%	26%	263-mile pipeline serving markets in the Northeast
	1,685		1,585
Other Equity Method Investees
Other Segments	177		186
	$	1,862	$	1,771

The balances in Other Equity Method Investees are individually insignificant and are primarily from the Power and Industrial Projects segment. These investments are comprised of projects that deliver energy and utility-type products and services to an industrial customer, sell electricity from renewable energy projects under long-term power purchase agreements, and produce and sell metallurgical coke.

For further information by segment, see Note 23 to the Consolidated Financial Statements, "Segment and Related Information."

The following table presents summarized financial information of subsidiaries not consolidated and 50 percent or less owned by DTE Energy. The amounts included in the table below represents 100% of the results of continuing operations of such entities accounted for under the equity method of accounting.

Summarized balance sheet data is as follows:



	December 31,
	2019		2018
	(In millions)
Current Assets	$	374	$	358
Non-current assets	$	5,260	$	5,101
Current Liabilities	$	414	$	391
Non-current liabilities	$	698	$	762

Summarized income statement data is as follows:



	December 31,
	2019		2018		2017
	(In millions)
Operating Revenues	$	1,210	$	883	$	756
Operating Expenses	$	853	$	622	$	561
Net Income	$	313	$	365	$	254

Significant Accounting Policies

12 Months Ended

Dec. 31, 2019

Accounting Policies [Abstract]

Significant Accounting Policies

SIGNIFICANT ACCOUNTING POLICIES

Other Income

Other income for the Registrants is recognized for non-operating income such as equity earnings of equity method investees, allowance for equity funds used during construction, contract services, and gains (losses) from trading securities. DTE Energy's Power and Industrial Projects segment also recognizes Other income in connection with the sale of membership interests in reduced emissions fuel facilities to investors. In exchange for the cash received, the investors will receive a portion of the economic attributes of the facilities, including income tax attributes. The transactions are not treated as a sale of membership interests for financial reporting purposes. Other income related to fixed non-refundable cash payments received from investors for which the earnings process is not contingent upon production of refined coal is recognized on a straight-line basis over the non-cancelable contract term as the economic benefit from the ownership of the facility is transferred to investors. Other income related to cash payments that is contingent upon production of refined coal is considered earned and recognized when the contingency regarding the timing and amount of payment is resolved, generally as refined coal is produced and tax credits are generated.

The following is a summary of DTE Energy's Other income:



	2019		2018		2017
	(In millions)
Income from REF entities	$	130	$	98	$	77
Equity earnings of equity method investees	111		132		102
Gains from equity securities	37		6		26
Contract services	29		51		19
Allowance for equity funds used during construction	24		28		23
Other	19		18		21
	$	350	$	333	$	268

The following is a summary of DTE Electric's Other income:



	2019		2018		2017
	(In millions)
Gains from equity securities allocated from DTE Energy	$	37	$	6	$	26
Contract services	32		51		21
Allowance for equity funds used during construction	22		19		18
Other	16		7		12
	$	107	$	83	$	77

For information on equity earnings of equity method investees by segment, see Note 23 to the Consolidated Financial Statements, "Segment and Related Information."

Accounting for ISO Transactions

DTE Electric participates in the energy market through MISO. MISO requires that DTE Electric submit hourly day-ahead, real-time, and FTR bids and offers for energy at locations across the MISO region. DTE Electric accounts for MISO transactions on a net hourly basis in each of the day-ahead, real-time, and FTR markets. In any single hour, transactions in each of the MISO energy markets are netted based on MWh to determine if DTE Electric is in a net sale or purchase position. Net purchases are recorded in Fuel, purchased power, and gas — utility and net sales are recorded in Operating Revenues — Utility operations on the Registrants' Consolidated Statements of Operations.

The Energy Trading segment participates in the energy markets through various ISOs and RTOs. These markets require that Energy Trading submits hourly day-ahead, real-time bids and offers for energy at locations across each region. Energy Trading submits bids in the annual and monthly auction revenue rights and FTR auctions to the RTOs. Energy Trading accounts for these transactions on a net hourly basis for the day-ahead, real-time, and FTR markets. These transactions are related to trading contracts which, if derivatives, are presented on a net basis in Operating Revenues — Non-utility operations, and if non-derivatives, the realized gains and losses for sales are recorded in Operating Revenues — Non-utility operations and purchases are recorded in Fuel, purchased power, and gas — non-utility in the DTE Energy Consolidated Statements of Operations.

DTE Electric and Energy Trading record accruals for future net purchases adjustments based on historical experience and reconcile accruals to actual costs when invoices are received from MISO and other ISOs and RTOs.

Derivatives

Energy Trading classifies derivative transactions as revenue or expense based on the intent of the transaction (buy or sell). Revenues are recorded on a gross or net basis within the income statement depending upon whether it represents a non-trading activity or trading activity, respectively. For additional information, refer to Note 14 to the Consolidated Financial Statements, "Financial and Other Derivative Instruments".

Changes in Accumulated Other Comprehensive Income (Loss)

Comprehensive income (loss) is the change in common shareholders’ equity during a period from transactions and events from non-owner sources, including Net Income. The amounts recorded to Accumulated other comprehensive income (loss) for DTE Energy include changes in benefit obligations, consisting of deferred actuarial losses and prior service costs, unrealized gains and losses from derivatives accounted for as cash flow hedges, DTE Energy's interest in other comprehensive income of equity investees which comprise the net unrealized gains and losses on investments, and foreign currency translation adjustments. DTE Energy releases income tax effects from accumulated other comprehensive income when the circumstances upon which they are premised cease to exist.

Changes in Accumulated other comprehensive income (loss) are presented in DTE Energy's Consolidated Statements of Changes in Equity and DTE Electric's Consolidated Statements of Changes in Shareholder's Equity. For further discussion regarding changes in Accumulated other comprehensive income (loss), see Note 3 to the Consolidated Financial Statements, "New Accounting Pronouncements." For the years ended December 31, 2019 and 2018, reclassifications out of Accumulated other comprehensive income (loss) not relating to the adoption of new accounting pronouncements for DTE Energy were not material.

The following table summarizes the changes in DTE Energy's Accumulated other comprehensive income (loss) by component^(a) for the years ended December 31, 2019 and 2018:



	Net Unrealized Gain (Loss) on Derivatives			Net Unrealized Loss on Investments			Benefit Obligations^(b)			Foreign Currency Translation			Total
	(In millions)
Balance, December 31, 2017	$	(3	)	$	(2	)	$	(110	)	$	(5	)	$	(120	)
Other comprehensive loss before reclassifications	(2		)	—			(1		)	(2		)	(5		)
Amounts reclassified from Accumulated other comprehensive income (loss)	1			—			9			—			10
Net current-period Other comprehensive income (loss)	(1		)	—			8			(2		)	5
Implementation of ASU 2016-01	(7		)	2			—			—			(5		)
Balance, December 31, 2018	$	(11	)	$	—		$	(102	)	$	(7	)	$	(120	)
Other comprehensive income (loss) before reclassifications	(14		)	—			(7		)	1			(20		)
Amounts reclassified from Accumulated other comprehensive income (loss)	2			—			15			—			17
Net current-period Other comprehensive income (loss)	(12		)	—			8			1			(3		)
Implementation of ASU 2018-02	(2		)	—			(23		)	—			(25		)
Balance, December 31, 2019	$	(25	)	$	—		$	(117	)	$	(6	)	$	(148	)

______________________________________


(a)	All amounts are net of tax, except for Foreign currency translation.


(b)	The amounts reclassified from Accumulated other comprehensive income (loss) are included in the computation of the net periodic pension and other postretirement benefit costs (see Note 21 to the Consolidated Financial Statements, "Retirement Benefits and Trusteed Assets").

Cash, Cash Equivalents, and Restricted Cash

Cash and cash equivalents include cash on hand, cash in banks, and temporary investments purchased with remaining maturities of three months or less. Restricted cash consists of funds held to satisfy requirements of certain debt and DTE Energy partnership operating agreements. Restricted cash designated for interest and principal payments within one year is classified as a Current Asset.

Receivables

Accounts receivable are primarily composed of trade receivables and unbilled revenue. The Registrants' Accounts receivable are stated at net realizable value.

The allowance for doubtful accounts for DTE Electric and DTE Gas is generally calculated using the aging approach that utilizes rates developed in reserve studies. DTE Electric and DTE Gas establish an allowance for uncollectible accounts based on historical losses and management’s assessment of existing economic conditions, customer trends, and other factors. Customer accounts are generally considered delinquent if the amount billed is not received by the due date, which is typically in 21 days, however, factors such as assistance programs may delay aggressive action. DTE Electric and DTE Gas assess late payment fees on trade receivables based on past-due terms with customers. Customer accounts are written off when collection efforts have been exhausted. The time period for write-off is 150 days after service has been terminated.

The customer allowance for doubtful accounts for DTE Energy's other businesses is calculated based on specific review of probable future collections based on receivable balances generally in excess of 30 days.

DTE Energy unbilled revenues of $0.9 billion and $1.0 billion at December 31, 2019 and 2018, respectively, include $263 million and $264 million of DTE Electric unbilled revenues, respectively, included in Customer Accounts receivable.

Notes Receivable

Notes receivable, or financing receivables, for DTE Energy are primarily comprised of finance lease receivables and loans and are included in Notes receivable and Other current assets on DTE Energy’s Consolidated Statements of Financial Position. Notes receivable, or financing receivables, for DTE Electric are primarily comprised of loans.

Notes receivable are typically considered delinquent when payment is not received for periods ranging from 60 to 120 days. The Registrants cease accruing interest (nonaccrual status), consider a note receivable impaired, and establish an allowance for credit loss when it is probable that all principal and interest amounts due will not be collected in accordance with the contractual terms of the note receivable. Cash payments received on nonaccrual status notes receivable, that do not bring the account contractually current, are first applied to contractually owed past due interest, with any remainder applied to principal. Accrual of interest is generally resumed when the note receivable becomes contractually current.

In determining the allowance for credit losses for notes receivable, the Registrants consider the historical payment experience and other factors that are expected to have a specific impact on the counterparty’s ability to pay. In addition, the Registrants monitor the credit ratings of the counterparties from which they have notes receivable.

Inventories

Inventory related to utility operations is generally valued at average cost. Inventory related to non-utility operations is valued at the lower of cost or net realizable value.

DTE Gas' natural gas inventory of $40 million and $48 million as of December 31, 2019 and 2018, respectively, is determined using the last-in, first-out (LIFO) method. The replacement cost of gas in inventory exceeded the LIFO cost by $49 million and $113 million at December 31, 2019 and 2018, respectively.

Property, Retirement and Maintenance, and Depreciation and Amortization

Property is stated at cost and includes construction-related labor, materials, overheads, and AFUDC for utility property. The cost of utility properties retired is charged to accumulated depreciation. Expenditures for maintenance and repairs are charged to expense when incurred.

Utility property at DTE Electric and DTE Gas is depreciated over its estimated useful life using straight-line rates approved by the MPSC. DTE Energy's non-utility property is depreciated over its estimated useful life using the straight-line method. Depreciation and amortization expense also includes the amortization of certain regulatory assets for the Registrants.

The cost of nuclear fuel is capitalized. The amortization of nuclear fuel is included within Fuel, purchased power, and gas — utility in the DTE Energy Consolidated Statements of Operations, and Fuel and purchased power in the DTE Electric Consolidated Statements of Operations, and is recorded using the units-of-production method.

See Note 7 to the Consolidated Financial Statements, "Property, Plant, and Equipment."

Long-Lived Assets

Long-lived assets are reviewed for impairment whenever events or changes in circumstances indicate the carrying amount of an asset may not be recoverable. If the carrying amount of the asset exceeds the expected undiscounted future cash flows generated by the asset, an impairment loss is recognized resulting in the asset being written down to its estimated fair value. Assets to be disposed of are reported at the lower of the carrying amount or fair value, less costs to sell.

Intangible Assets

The Registrants have certain Intangible assets as shown below:



		December 31, 2019							December 31, 2018
	Useful Lives	Gross Carrying Value		Accumulated Amortization			Net Carrying Value		Gross Carrying Value		Accumulated Amortization			Net Carrying Value
		(In millions)
Intangible assets subject to amortization
Customer relationships	25 to 40 years^(a)	$	2,252	$	(66	)	$	2,186	$	779	$	(44	)	$	735
Contract intangibles	6 to 26 years	268		(76		)	192		159		(66		)	93
		2,520		(142		)	2,378		938		(110		)	828

DTE Electric renewable energy credits	(b)	15		—			15		20		—			20
DTE Electric emission allowances	(b)	—		—			—		1		—			1
DTE Electric Long-term intangible assets		15		—			15		21		—			21

DTE Energy Long-term intangible assets		$	2,535	$	(142	)	$	2,393	$	959	$	(110	)	$	849

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(a)	The useful lives of the customer relationship intangible assets are based on the number of years in which the assets are expected to economically contribute to the business. The expected economic benefit incorporates existing customer contracts and expected renewal rates based on the estimated volume and production lives of gas resources in the region.


(b)	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 following table summarizes DTE Energy's estimated customer relationship and contract intangible amortization expense expected to be recognized during each year through 2024:



	2020		2021		2022		2023		2024
	(In millions)
Estimated amortization expense	$	82	$	86	$	86	$	86	$	86

DTE Energy amortizes customer relationship and contract intangible assets on a straight-line basis over the expected period of benefit. DTE Energy's Intangible assets amortization expense was $33 million in 2019, $27 million in 2018, and $29 million in 2017.

Excise and Sales Taxes

The Registrants record the billing of excise and sales taxes as a receivable with an offsetting payable to the applicable taxing authority, with no net impact on the Registrants’ Consolidated Statements of Operations.

Deferred Debt Costs

The costs related to the issuance of long-term debt are deferred and amortized over the life of each debt issue. The deferred amounts are included as a direct deduction from the carrying amount of each debt issue in Mortgage bonds, notes, and other and Junior subordinated debentures on DTE Energy's Consolidated Statements of Financial Position and in Mortgage bonds, notes, and other on DTE Electric's Consolidated Statements of Financial Position. In accordance with MPSC regulations applicable to DTE Energy’s electric and gas utilities, the unamortized discount, premium, and expense related to utility debt redeemed with a refinancing are amortized over the life of the replacement issue. Discount, premium, and expense on early redemptions of debt associated with DTE Energy's non-utility operations are charged to earnings.