DTE Energy (DTE) 10-Q27 Oct 212021 Q3 Quarterly reportFinancial data

Company Profile

Document and Entity Information

Document and Entity Information	9 Months Ended
Document and Entity Information	Sep. 30, 2021shares
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Sep. 30, 2021
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 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 Common Stock, Shares Outstanding	193,727,278
Entity Central Index Key	0000936340
Current Fiscal Year End Date	--12-31
Document Fiscal Year Focus	2021
Document Fiscal Period Focus	Q3
Amendment Flag	false
DTE Electric
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 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
Common stock, without par value
Title of 12(b) Security	Common stock, without par value
Trading Symbol	DTE
Security Exchange Name	NYSE
2016 Series F 6.00% Junior Subordinated Debentures due 2076
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
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
Title of 12(b) Security	2019 6.25% Corporate Units
Trading Symbol	DTP
Security Exchange Name	NYSE
2020 Series G 4.375% Junior Subordinated Debentures due 2080
Title of 12(b) Security	2020 Series G 4.375% Junior Subordinated Debentures due 2080
Trading Symbol	DTB
Security Exchange Name	NYSE

Consolidated Statements of Oper

Consolidated Statements of Operations (Unaudited) - USD ($) shares in Millions, $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Operating Revenues
Utility operations	$ 1,875	$ 1,844	$ 5,483	$ 5,119
Non-utility operations	1,840	1,236	4,834	3,224
Operating Revenues	3,715	3,080	10,317	8,343
Operating Expenses
Fuel, purchased power, and gas — utility	477	455	1,411	1,296
Fuel, purchased power, gas, and other — non-utility	1,766	1,174	4,708	2,923
Operation and maintenance	615	556	1,750	1,651
Depreciation and amortization	344	318	1,010	949
Taxes other than income	106	100	329	294
Asset (gains) losses and impairments, net	2	(2)	29	43
Operating Expenses	3,310	2,601	9,237	7,156
Operating Income	405	479	1,080	1,187
Other (Income) and Deductions
Interest expense	156	149	477	450
Interest income	(6)	(11)	(16)	(25)
Non-operating retirement benefits, net	3	5	10	20
Loss on extinguishment of debt	376	0	384	0
Other income	(90)	(75)	(187)	(188)
Other expenses	30	20	50	72
Other (Income) and Deductions	469	88	718	329
Income (Loss) Before Income Taxes	(64)	391	362	858
Income Tax Expense (Benefit) (Note 2)	(119)	21	(124)	19
Net Income from Continuing Operations	55	370	486	839
Income (Loss) from Discontinued Operations, Net of Taxes (Note 4)	(33)	107	112	257
Net Income	22	477	598	1,096
Less: Net Income (Loss) Attributable to Noncontrolling Interests
Continuing operations	(3)	(2)	(9)	(5)
Discontinued operations	0	3	6	8
Net Income Attributable to DTE Energy Company/DTE Electric Company	$ 25	$ 476	$ 601	$ 1,093
Basic Earnings per Common Share
Continuing operations (in dollars per share)	$ 0.30	$ 1.93	$ 2.55	$ 4.37
Discontinued operations (in dollars per share)	(0.17)	0.54	0.55	1.30
Basic Earnings per Common Share (in dollars per share)	0.13	2.47	3.10	5.67
Diluted Earnings per Common Share
Continuing operations (in dollars per share)	0.30	1.92	2.55	4.37
Discontinued operations (in dollars per share)	(0.17)	0.54	0.55	1.29
Diluted Earnings per Common Share (in dollars per share)	$ 0.13	$ 2.46	$ 3.10	$ 5.66
Weighted Average Common Shares Outstanding
Basic (in shares)	193	193	193	192
Diluted (in shares)	194	193	194	193
DTE Electric
Operating Revenues
Utility operations	$ 1,700	$ 1,690	$ 4,468	$ 4,211
Operating Expenses
Fuel, purchased power, and gas — utility	462	451	1,185	1,090
Operation and maintenance	410	361	1,122	1,074
Depreciation and amortization	278	258	810	768
Taxes other than income	83	79	245	220
Asset (gains) losses and impairments, net	0	0	0	41
Operating Expenses	1,233	1,149	3,362	3,193
Operating Income	467	541	1,106	1,018
Other (Income) and Deductions
Interest expense	84	83	251	249
Interest income	0	0	0	(2)
Non-operating retirement benefits, net	0	0	(1)	0
Other income	(14)	(18)	(52)	(68)
Other expenses	8	18	26	66
Other (Income) and Deductions	78	83	224	245
Income (Loss) Before Income Taxes	389	458	882	773
Income Tax Expense (Benefit) (Note 2)	45	58	92	96
Less: Net Income (Loss) Attributable to Noncontrolling Interests
Net Income Attributable to DTE Energy Company/DTE Electric Company	$ 344	$ 400	$ 790	$ 677

Consolidated Statements of Comp

Consolidated Statements of Comprehensive Income (Unaudited) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Net Income	$ 22	$ 477	$ 598	$ 1,096
Net Income	25	476	601	1,093
Other comprehensive income, net of tax:
Benefit obligations, net of taxes of $1, $1, $2, and $3, respectively	2	2	5	7
Net unrealized gains (losses) on derivatives, net of taxes of $1, $—, $2, and $1, respectively	4	1	6	3
Other comprehensive income	6	3	11	10
Comprehensive income	28	480	609	1,106
Less: Comprehensive income (loss) attributable to noncontrolling interests	(3)	1	(3)	3
Comprehensive Income (Loss) Attributable to DTE Energy Company/DTE Electric Company	31	479	612	1,103
DTE Electric
Net Income	344	400	790	677
Other comprehensive income, net of tax:
Other comprehensive income	0	0	0	0
Comprehensive Income (Loss) Attributable to DTE Energy Company/DTE Electric Company	$ 344	$ 400	$ 790	$ 677

Consolidated Statements of Co_2

Consolidated Statements of Comprehensive Income (Unaudited) (Parenthetical) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Statement of Comprehensive Income [Abstract]
Tax effect on benefit obligations	$ 1	$ 1	$ 2	$ 3
Tax effect on net unrealized gains (losses) on derivatives during the period	$ 1	$ 0	$ 2	$ 1

Consolidated Statements of Fina

Consolidated Statements of Financial Position (Unaudited) - USD ($) $ in Millions	Sep. 30, 2021	Dec. 31, 2020
Current Assets
Cash and cash equivalents	$ 54	$ 472
Restricted cash	2	2
Accounts receivable (less allowance for doubtful accounts)
Customer	1,522	1,542
Other	170	127
Inventories
Fuel and gas	398	335
Materials, supplies, and other	517	373
Derivative assets	347	116
Regulatory assets	187	129
Other	297	185
Current assets of discontinued operations	0	217
Total Current Assets	3,494	3,498
Investments
Nuclear decommissioning trust funds	2,007	1,855
Investments in equity method investees	186	177
Other	187	196
Total Investments	2,380	2,228
Property
Property, plant, and equipment	36,134	34,016
Accumulated depreciation and amortization	(9,977)	(9,517)
Property, plant, and equipment, net	26,157	24,499
Other Assets
Goodwill	1,993	1,993
Regulatory assets	3,974	4,125
Intangible assets	181	199
Notes receivable	304	261
Derivative assets	81	40
Prepaid postretirement costs	620	561
Operating lease right-of-use assets	100	107
Other	151	126
Noncurrent assets of discontinued operations	0	7,859
Total Other Assets	7,404	15,271
Total Assets	39,435	45,496
Accounts payable
Accounts payable	1,365	1,000
Accrued interest	147	158
Dividends payable	160	210
Short-term borrowings	361	38
Current portion long-term debt, including finance leases	324	469
Derivative liabilities	465	68
Regulatory liabilities	41	39
Short-term borrowings
Operating lease liabilities	14	16
Other	556	594
Current liabilities of discontinued operations	0	99
Total Current Liabilities	3,433	2,691
Long-Term Debt (net of current portion)
Mortgage bonds, notes, and other	16,022	17,802
Junior subordinated debentures	883	1,175
Finance lease liabilities	19	24
Total Long-Term Debt (net of current portion)	16,924	19,001
Other Liabilities
Deferred income taxes	2,105	2,069
Regulatory liabilities	3,220	3,363
Asset retirement obligations	2,974	2,829
Unamortized investment tax credit	158	162
Derivative liabilities	244	60
Accrued pension liability	732	797
Accrued postretirement liability	398	407
Nuclear decommissioning	310	283
Operating lease liabilities	77	83
Other	281	326
Noncurrent liabilities of discontinued operations	0	836
Total Other Liabilities	10,499	11,215
Commitments and Contingencies (Notes 6 and 13)
Equity
Common stock	5,366	5,406
Retained earnings	3,317	7,156
Accumulated other comprehensive loss	(116)	(137)
Total DTE Energy/DTE Electric Company Equity	8,567	12,425
Total Equity	8,579	12,589
Total Liabilities and Equity	39,435	45,496
Continuing Operations
Equity
Noncontrolling interests	12	10
Discontinued Operations
Equity
Noncontrolling interests	0	154
DTE Electric
Current Assets
Cash and cash equivalents	18	16
Accounts receivable (less allowance for doubtful accounts)
Customer	782	763
Affiliates	17	13
Other	64	62
Inventories
Fuel and gas	175	187
Materials, supplies, and other	320	292
Regulatory assets	178	123
Prepaid property tax	126	52
Other	43	19
Total Current Assets	1,723	1,527
Investments
Nuclear decommissioning trust funds	2,007	1,855
Other	41	42
Total Investments	2,048	1,897
Property
Property, plant, and equipment	28,014	26,171
Accumulated depreciation and amortization	(7,506)	(7,050)
Property, plant, and equipment, net	20,508	19,121
Other Assets
Regulatory assets	3,335	3,440
Intangible assets	3	11
Prepaid postretirement costs — affiliates	371	335
Operating lease right-of-use assets	67	75
Other	120	107
Total Other Assets	3,896	3,968
Total Assets	28,175	26,513
Accounts payable
Affiliates	64	62
Other	582	410
Accrued interest	87	91
Current portion long-term debt, including finance leases	322	468
Regulatory liabilities	36	18
Short-term borrowings
Affiliates	32	101
Other	159	0
Operating lease liabilities	11	11
Other	165	219
Total Current Liabilities	1,458	1,380
Long-Term Debt (net of current portion)
Mortgage bonds, notes, and other	8,590	7,774
Finance lease liabilities	9	13
Total Long-Term Debt (net of current portion)	8,599	7,787
Other Liabilities
Deferred income taxes	2,677	2,525
Regulatory liabilities	2,322	2,432
Asset retirement obligations	2,744	2,607
Unamortized investment tax credit	158	162
Nuclear decommissioning	310	283
Accrued pension liability — affiliates	697	731
Accrued postretirement liability — affiliates	378	384
Operating lease liabilities	49	56
Other	91	96
Total Other Liabilities	9,426	9,276
Commitments and Contingencies (Notes 6 and 13)
Equity
Common stock	5,720	5,447
Retained earnings	2,972	2,623
Total DTE Energy/DTE Electric Company Equity	8,692	8,070
Total Liabilities and Equity	$ 28,175	$ 26,513

Consolidated Statements of Fi_2

Consolidated Statements of Financial Position (Unaudited) (Parenthetical) - USD ($) $ in Millions	Sep. 30, 2021	Dec. 31, 2020
Current Assets
Allowance for doubtful accounts	$ 102	$ 104
Shareholder’s Equity
Common stock, shares authorized (in shares)	400,000,000	400,000,000
Common stock, shares issued (in shares)	193,727,278	193,770,617
Common stock, shares outstanding (in shares)	193,727,278	193,770,617
DTE Electric
Current Assets
Allowance for doubtful accounts	$ 55	$ 57
Shareholder’s Equity
Par value (in dollars per share)	$ 10	$ 10
Common stock, shares authorized (in shares)	400,000,000	400,000,000
Common stock, shares issued (in shares)	138,632,324	138,632,324
Common stock, shares outstanding (in shares)	138,632,324	138,632,324

Consolidated Statements of Cash

Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020
Operating Activities
Net Income	$ 598	$ 1,096
Net Income	601	1,093
Adjustments to reconcile Net Income to Net cash from operating activities:
Depreciation and amortization	1,092	1,059
Nuclear fuel amortization	44	22
Allowance for equity funds used during construction	(20)	(19)
Deferred income taxes	(36)	350
Equity earnings of equity method investees	(90)	(96)
Dividends from equity method investees	78	122
Loss on extinguishment of debt	384	0
Asset (gains) losses and impairments, net	46	44
Changes in assets and liabilities:
Accounts receivable, net	(8)	343
Inventories	(209)	(54)
Prepaid postretirement benefit costs	(59)	(56)
Accounts payable	225	(80)
Accrued pension liability	(65)	(126)
Accrued postretirement liability	(9)	0
Derivative assets and liabilities	309	15
Regulatory assets and liabilities	270	(30)
Other current and noncurrent assets and liabilities	(178)	191
Net cash from operating activities	2,372	2,781
Investing Activities
Plant and equipment expenditures — utility	(2,591)	(2,362)
Plant and equipment expenditures — non-utility	(109)	(526)
Acquisitions related to business combinations, net of cash acquired	0	(126)
Proceeds from sale of assets	2	7
Proceeds from sale of nuclear decommissioning trust fund assets	854	2,054
Investment in nuclear decommissioning trust funds	(853)	(2,051)
Distributions from equity method investees	11	6
Contributions to equity method investees	(7)	(32)
Notes receivable	(65)	(58)
Other	(22)	(5)
Net cash used for investing activities	(2,780)	(3,093)
Financing Activities
Issuance of long-term debt, net of discount and issuance costs	4,033	2,724
Redemption of long-term debt	(3,242)	(682)
Short-term borrowings, net	323	160
Repurchase of common stock	(66)	0
Dividends paid on common stock	(631)	(574)
Contributions from noncontrolling interests, principally REF entities	35	25
Distributions to noncontrolling interests	(33)	(27)
Acquisition related deferred payment, excluding accretion	0	(380)
Prepayment costs for extinguishment of long-term debt	(361)	0
Transfer of cash to DT Midstream at separation	(37)	0
Other	(73)	(65)
Net cash from (used for) financing activities	(52)	1,181
Net Increase (Decrease) in Cash, Cash Equivalents, and Restricted Cash	(460)	869
Cash, Cash Equivalents, and Restricted Cash at Beginning of Period	516	93
Cash, Cash Equivalents, and Restricted Cash at End of Period	56	962
Supplemental disclosure of non-cash investing and financing activities
Plant and equipment expenditures in accounts payable	386	282
Separation of DT Midstream net assets, excluding cash transferred	3,962	0
DTE Electric
Operating Activities
Net Income	790	677
Adjustments to reconcile Net Income to Net cash from operating activities:
Depreciation and amortization	810	768
Nuclear fuel amortization	44	22
Allowance for equity funds used during construction	(18)	(18)
Deferred income taxes	90	74
Asset (gains) losses and impairments, net	0	41
Changes in assets and liabilities:
Accounts receivable, net	(25)	(71)
Inventories	(19)	(30)
Accounts payable	40	37
Prepaid postretirement benefit costs — affiliates	(36)	0
Accrued pension liability — affiliates	(34)	(80)
Accrued postretirement liability — affiliates	(6)	(35)
Regulatory assets and liabilities	229	(79)
Other current and noncurrent assets and liabilities	(259)	(20)
Net cash from operating activities	1,606	1,286
Investing Activities
Plant and equipment expenditures	(2,152)	(1,981)
Proceeds from sale of nuclear decommissioning trust fund assets	854	2,054
Investment in nuclear decommissioning trust funds	(853)	(2,051)
Notes Receivable and Other	(22)	(14)
Net cash used for investing activities	(2,173)	(1,992)
Financing Activities
Issuance of long-term debt, net of discount and issuance costs	986	1,683
Redemption of long-term debt	(321)	(632)
Capital contribution by parent company	273	400
Short-term borrowings, net — affiliate	(69)	7
Short-term borrowings, net — other	159	(154)
Dividends paid on common stock	(441)	(404)
Other	(18)	(17)
Net cash from (used for) financing activities	569	883
Net Increase (Decrease) in Cash, Cash Equivalents, and Restricted Cash	2	177
Cash, Cash Equivalents, and Restricted Cash at Beginning of Period	16	12
Cash, Cash Equivalents, and Restricted Cash at End of Period	18	189
Supplemental disclosure of non-cash investing and financing activities
Plant and equipment expenditures in accounts payable	$ 307	$ 141

Consolidated Statements of Chan

Consolidated Statements of Changes in Equity (Unaudited) - USD ($) $ in Millions	Total	Common Stock	Retained Earnings	Accumulated Other Comprehensive Income (Loss)	Noncontrolling Interests	DTE Electric	DTE ElectricCommon Stock	DTE ElectricAdditional Paid-in Capital	DTE ElectricRetained Earnings
Beginning Balance (in shares) at Dec. 31, 2019		192,209,000					138,632,000
Beginning Balance at Dec. 31, 2019	$ 11,836	$ 5,233	$ 6,587	$ (148)	$ 164
Beginning Balance at Dec. 31, 2019						$ 7,195	$ 1,386	$ 3,425	$ 2,384
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net Income (Loss)	342		340		2
Net Income						94			94
Dividends declared on common stock	(195)		(195)			(135)			(135)
Other comprehensive income , net of tax	3			3
Stock-based compensation, net distributions/contributions to/from noncontrolling interests, and other (in shares)		403,000
Stock-based compensation, net distributions/contributions to/from noncontrolling interests, and other	2	$ 2
Ending Balance (in shares) at Mar. 31, 2020		192,612,000					138,632,000
Ending Balance at Mar. 31, 2020	11,988	$ 5,235	6,732	(145)	166
Ending Balance at Mar. 31, 2020						7,154	$ 1,386	3,425	2,343
Beginning Balance (in shares) at Dec. 31, 2019		192,209,000					138,632,000
Beginning Balance at Dec. 31, 2019	11,836	$ 5,233	6,587	(148)	164
Beginning Balance at Dec. 31, 2019						7,195	$ 1,386	3,425	2,384
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net Income (Loss)	1,096
Net Income	1,093					677
Other comprehensive income , net of tax	10					0
Ending Balance (in shares) at Sep. 30, 2020		193,560,000					138,632,000
Ending Balance at Sep. 30, 2020	12,488	$ 5,369	7,092	(138)	165
Ending Balance at Sep. 30, 2020						7,868	$ 1,386	3,825	2,657
Beginning Balance (in shares) at Mar. 31, 2020		192,612,000					138,632,000
Beginning Balance at Mar. 31, 2020	11,988	$ 5,235	6,732	(145)	166
Beginning Balance at Mar. 31, 2020						7,154	$ 1,386	3,425	2,343
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net Income (Loss)	277		277		0
Net Income						183			183
Dividends declared on common stock	(390)		(390)			(134)			(134)
Other comprehensive income , net of tax	4			4
Stock-based compensation, net distributions/contributions to/from noncontrolling interests, and other (in shares)		39,000
Stock-based compensation, net distributions/contributions to/from noncontrolling interests, and other	13	$ 12	(1)		2
Ending Balance (in shares) at Jun. 30, 2020		192,651,000					138,632,000
Ending Balance at Jun. 30, 2020	11,892	$ 5,247	6,618	(141)	168
Ending Balance at Jun. 30, 2020						7,203	$ 1,386	3,425	2,392
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net Income (Loss)	477		476		1
Net Income	476					400			400
Dividends declared on common stock						(135)			(135)
Issuance of common stock (in shares)		98,000
Issuance of common stock	11	$ 11
Contribution of common stock to pension plan (in shares)		694,000
Contribution of common stock to pension plan	82	$ 82
Other comprehensive income , net of tax	3			3		0
Stock-based compensation, net distributions/contributions to/from noncontrolling interests, and other (in shares)		117,000
Stock-based compensation, net distributions/contributions to/from noncontrolling interests, and other	23	$ 29	(2)		(4)
Capital contribution by parent company						400		400
Ending Balance (in shares) at Sep. 30, 2020		193,560,000					138,632,000
Ending Balance at Sep. 30, 2020	$ 12,488	$ 5,369	7,092	(138)	165
Ending Balance at Sep. 30, 2020						$ 7,868	$ 1,386	3,825	2,657
Beginning Balance (in shares) at Dec. 31, 2020	193,770,617	193,771,000				138,632,324	138,632,000
Beginning Balance at Dec. 31, 2020	$ 12,589	$ 5,406	7,156	(137)	164
Beginning Balance at Dec. 31, 2020	12,425					$ 8,070	$ 1,386	4,061	2,623
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net Income (Loss)	397		397
Net Income						208			208
Dividends declared on common stock	(210)		(210)			(147)			(147)
Repurchase of common stock (in shares)		(430,000)
Repurchase of common stock	(54)	$ (54)
Other comprehensive income , net of tax	3			3
Stock-based compensation, net distributions/contributions to/from noncontrolling interests, and other (in shares)		386,000
Stock-based compensation, net distributions/contributions to/from noncontrolling interests, and other	(11)	$ (8)	(1)		(2)
Ending Balance (in shares) at Mar. 31, 2021		193,727,000					138,632,000
Ending Balance at Mar. 31, 2021	$ 12,714	$ 5,344	7,342	(134)	162
Ending Balance at Mar. 31, 2021						$ 8,131	$ 1,386	4,061	2,684
Beginning Balance (in shares) at Dec. 31, 2020	193,770,617	193,771,000				138,632,324	138,632,000
Beginning Balance at Dec. 31, 2020	$ 12,589	$ 5,406	7,156	(137)	164
Beginning Balance at Dec. 31, 2020	12,425					$ 8,070	$ 1,386	4,061	2,623
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net Income (Loss)	598
Net Income	601					790
Other comprehensive income , net of tax	$ 11					$ 0
Ending Balance (in shares) at Sep. 30, 2021	193,727,278	193,727,000				138,632,324	138,632,000
Ending Balance at Sep. 30, 2021	$ 8,579	$ 5,366	3,317	(116)	12
Ending Balance at Sep. 30, 2021	8,567					$ 8,692	$ 1,386	4,334	2,972
Beginning Balance (in shares) at Mar. 31, 2021		193,727,000					138,632,000
Beginning Balance at Mar. 31, 2021	12,714	$ 5,344	7,342	(134)	162
Beginning Balance at Mar. 31, 2021						8,131	$ 1,386	4,061	2,684
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net Income (Loss)	179		179
Net Income						238			238
Dividends declared on common stock	(370)		(370)			(146)			(146)
Other comprehensive income , net of tax	2			2
Stock-based compensation, net distributions/contributions to/from noncontrolling interests, and other (in shares)		25,000
Stock-based compensation, net distributions/contributions to/from noncontrolling interests, and other	14	$ 17	(2)		(1)
Ending Balance (in shares) at Jun. 30, 2021		193,752,000					138,632,000
Ending Balance at Jun. 30, 2021	12,539	$ 5,361	7,149	(132)	161
Ending Balance at Jun. 30, 2021						8,223	$ 1,386	4,061	2,776
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net Income (Loss)	22		25		(3)
Net Income	25					344			344
Dividends declared on common stock						(148)			(148)
Repurchase of common stock (in shares)		(99,000)
Repurchase of common stock	(12)	$ (12)
Other comprehensive income , net of tax	6			6		0
Stock-based compensation, net distributions/contributions to/from noncontrolling interests, and other (in shares)		74,000
Stock-based compensation, net distributions/contributions to/from noncontrolling interests, and other	23	$ 17	1		5
Separation of DT Midstream	$ (3,999)		(3,858)	10	(151)
Capital contribution by parent company						$ 273		273
Ending Balance (in shares) at Sep. 30, 2021	193,727,278	193,727,000				138,632,324	138,632,000
Ending Balance at Sep. 30, 2021	$ 8,579	$ 5,366	$ 3,317	$ (116)	$ 12
Ending Balance at Sep. 30, 2021	$ 8,567					$ 8,692	$ 1,386	$ 4,334	$ 2,972

Consolidated Statements of Ch_2

Consolidated Statements of Changes in Equity (Unaudited) (Parenthetical) - $ / shares	3 Months Ended
	Jun. 30, 2021	Mar. 31, 2021	Jun. 30, 2020	Mar. 31, 2020
Statement of Stockholders' Equity [Abstract]
Dividends declared on common stock (in dollars per share)	$ 1.91	$ 1.09	$ 2.03	$ 1.01

Organization and Basis of Prese

Organization and Basis of Presentation	9 Months Ended
Organization and Basis of Presentation	Sep. 30, 2021
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 2.3 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 include (1) DTE Vantage, formerly DTE Energy's Power and Industrial Projects segment, which is primarily involved in providing industrial energy services, reduced emissions fuel projects, and renewable natural gas projects, and 2) 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, EGLE, and for DTE Energy, the CFTC and CARB. Basis of Presentation The Consolidated Financial Statements should be read in conjunction with the Combined Notes to Consolidated Financial Statements included in the combined DTE Energy and DTE Electric 2020 Annual Report on Form 10-K. The accompanying Consolidated Financial Statements of the Registrants are prepared using accounting principles generally accepted in the United States of America. These accounting principles require management to use estimates and assumptions that impact reported amounts of assets, liabilities, revenues and expenses, and the disclosure of contingent assets and liabilities. Actual results may differ from the Registrants' estimates. The Consolidated Financial Statements are unaudited but, in the Registrants' opinions, include all adjustments necessary to present a fair statement of the results for the interim periods. All adjustments are of a normal recurring nature, except as otherwise disclosed in these Consolidated Financial Statements and Combined Notes to Consolidated Financial Statements. Financial results for this interim period are not necessarily indicative of results that may be expected for any other interim period or for the fiscal year ending December 31, 2021. 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 DTE Electric were reclassified to match the current year's Consolidated Financial Statements presentation. Separation of DT Midstream On July 1, 2021, DTE Energy completed the previously announced separation of its natural gas pipeline, storage and gathering non-utility business. Effective with the separation, DTE retains no ownership in the new company, DT Midstream, which was formerly comprised of DTE Energy's Gas Storage and Pipelines segment and also included certain DTE Energy holding company activity within the Corporate and Other segment. Gas Storage and Pipelines is no longer a reportable segment of DTE Energy, and financial results of DT Midstream are presented as Income from discontinued operations, net of taxes on DTE Energy's Consolidated Statements of Operations. Assets and liabilities of DT Midstream are also presented as discontinued operations on DTE Energy's Consolidated Statements of Financial Position. Prior periods have been recast to reflect this presentation. No adjustments were made to the historical activity within the Consolidated Statements of Comprehensive Income, Consolidated Statements of Cash Flows, or the Consolidated Statements of Changes in Equity. Unless noted otherwise, discussion in the Notes to the Consolidated Financial Statements relate to continuing operations. Refer to Note 4 to the Consolidated Financial Statements, “Dispositions and Impairments,” for additional information regarding the separation of DT Midstream and discontinued operations. 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 equity investment is valued at cost minus any impairments, if applicable. 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. During the third quarter of 2021, the Registrants performed reassessments of certain VIEs owned by DT Midstream. Upon the separation of DT Midstream, DTE Energy no longer owns any interest in SGG, owner and operator of certain midstream natural gas assets. Therefore, SGG has been removed from the amounts for DTE Energy's consolidated VIEs in the table below. Additionally, as a result of the separation of DT Midstream, DTE Energy no longer has an equity interest in NEXUS, owner of a 256-mile pipeline which transports shale gas to Ohio, Michigan, and Ontario market centers. DTE Energy has removed its equity investment in NEXUS from the amounts for its non-consolidated VIEs. The Registrants maintain a variable interest in NEXUS relating to DTE Electric's transportation services contract. Assets, liabilities, and earnings related to SGG and NEXUS are included in discontinued operations in the Consolidated Financial Statements. Legal entities within the DTE Vantage 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. The Registrants hold ownership interests in certain limited partnerships. The limited partnerships include investment funds which support regional development and economic growth, and 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 September 30, 2021, 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 September 30, 2021, 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 13 to the Consolidated Financial Statements, "Commitments and Contingencies," related to 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. The following table summarizes the major Consolidated Statements of Financial Position items for consolidated VIEs as of September 30, 2021 and December 31, 2020. 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: September 30, 2021 December 31, 2020 (In millions) ASSETS Cash and cash equivalents $ 23 $ 20 Accounts receivable 26 28 Inventories 45 107 Property, plant, and equipment, net 5 14 Notes receivable and other 67 33 $ 166 $ 202 LIABILITIES Accounts payable $ 21 $ 22 Short-term borrowings 74 38 Other current and long-term liabilities 2 4 $ 97 $ 64 Amounts for DTE Energy's non-consolidated VIEs are as follows: September 30, 2021 December 31, 2020 (In millions) Investments in equity method investees $ 170 $ 159 Notes receivable $ 16 $ 21 Future funding commitments $ 3 $ 6

Significant Accounting Policies

Significant Accounting Policies	9 Months Ended
Significant Accounting Policies	Sep. 30, 2021
Accounting Policies [Abstract]
Significant Accounting Policies	SIGNIFICANT ACCOUNTING POLICIES Other Income The following is a summary of DTE Energy's Other income: Three Months Ended September 30, Nine Months Ended September 30, 2021 2020 2021 2020 (In millions) Income from REF entities $ 57 $ 43 $ 102 $ 95 Equity earnings of equity method investees 17 12 31 21 Contract services 6 7 21 20 Allowance for equity funds used during construction 7 6 20 19 Gains from rabbi trust securities (a) — 2 4 24 Other 3 5 9 9 $ 90 $ 75 $ 187 $ 188 _______________________________________ (a) Losses from rabbi trust securities are recorded separately to Other expenses on the Consolidated Statements of Operations. The following is a summary of DTE Electric's Other income: Three Months Ended September 30, Nine Months Ended September 30, 2021 2020 2021 2020 (In millions) Contract services $ 6 $ 7 $ 21 $ 20 Allowance for equity funds used during construction 6 6 18 18 Gains from rabbi trust securities allocated from DTE Energy (a) — 2 4 24 Other 2 3 9 6 $ 14 $ 18 $ 52 $ 68 _______________________________________ (a) Losses from rabbi trust securities are recorded separately to Other expenses on the Consolidated Statements of Operations. 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, 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 DTE Energy, this includes a one-time reduction of $10 million in Accumulated other comprehensive loss due to the Separation of DT Midstream in the third quarter 2021. For the three and nine months ended months ended September 30, 2021 and 2020, reclassifications out of Accumulated other comprehensive income (loss) were not material. Income Taxes The interim effective tax rates of the Registrants are as follows: Effective Tax Rate Three Months Ended September 30, Nine Months Ended September 30, 2021 2020 2021 2020 DTE Energy 186 % 5 % (34) % 2 % DTE Electric 12 % 13 % 10 % 12 % These tax rates are affected by estimated annual permanent items, including AFUDC equity, production tax credits, and other flow-through items, as well as discrete items that may occur in any given period, but are not consistent from period to period. DTE Energy's effective tax rates in 2021 have been significantly impacted by pre-tax losses in the third quarter, driven primarily by the loss on extinguishment of debt and reclassification of DT Midstream earnings to discontinued operations. The 181% increase in DTE Energy's effective tax rate for the three months ended September 30, 2021 was primarily due to a deferred tax remeasurement of 133%, production tax credits of 51%, and amortization of the TCJA regulatory liability of 35%, partially offset by a valuation allowance of 29% and recognition of a deferred intercompany gain of 13%. The 36% decrease in DTE Energy’s effective tax rate for the nine months ended September 30, 2021 was primarily due to a deferred tax remeasurement of 23%, production tax credits of 13%, and amortization of the TCJA regulatory liability of 9%, partially offset by the 2020 carryback of 2018 net operating losses due to the CARES Act of 4%, a valuation allowance of 4%, recognition of a deferred intercompany gain of 2%, and West Virginia tax law change of 2% in 2021. The valuation allowance referenced above was established in the third quarter 2021 based on a change in DTE Energy's assessment of its ability to utilize certain charitable contribution carryforwards. The valuation allowance resulted in $18 million of deferred tax expense and was reflected in Income Tax Expense (Benefit) in the Consolidated Statements of Operations for the three and nine months ended September 30, 2021. For the deferred tax remeasurement and deferred intercompany gain noted above, refer to the "Separation of DT Midstream - Tax Impacts" section below for additional information. The 1% decrease in DTE Electric's effective tax rate for the three months ended September 30, 2021 was primarily due to production tax credits. The 2% decrease in DTE Electric's effective tax rate for the nine months ended September 30, 2021 was primarily due to production tax credits of 1% and amortization of the TCJA regulatory liability of 1%. DTE Electric had income tax receivables with DTE Energy of $11 million and $8 million at September 30, 2021 and December 31, 2020, respectively. Separation of DT Midstream - Tax Impacts On July 1, 2021, DTE Energy completed the separation of its natural gas pipeline, storage and gathering non-utility business, DT Midstream. Refer to Note 4 to the Consolidated Financial Statements, "Dispositions and Impairments" for additional information regarding the separation. The separation was a tax free distribution to shareholders, but triggered certain tax effects at DTE Energy including the remeasurement of state deferred tax assets and liabilities and the recognition of a deferred intercompany gain. The state remeasurement reduced deferred tax liabilities and generated a deferred tax benefit of $85 million. The recognition of the deferred intercompany gain resulted in $9 million of additional deferred tax expense. Both of these impacts were reflected in Income Tax Expense (Benefit) in the Consolidated Statements of Operations for the three and nine months ended September 30, 2021. Unrecognized Compensation Costs As of September 30, 2021, DTE Energy had $76 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 1.4 years. Allocated Stock-Based Compensation DTE Electric received an allocation of costs from DTE Energy associated with stock-based compensation of $10 million and $12 million for the three months ended September 30, 2021 and 2020, respectively, while such allocation was $35 million and $28 million for the nine months ended September 30, 2021 and 2020, respectively. 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 in separate bank accounts to satisfy contractual obligations and guarantee performance. Restricted cash designated for payments within one year is classified as a Current Asset. Financing Receivables Financing receivables are primarily composed of trade receivables, notes receivable, and unbilled revenue. The Registrants' financing receivables are stated at net realizable value. The Registrants monitor the credit quality of their financing receivables on a regular basis by reviewing credit quality indicators and monitoring for trigger events, such as a credit rating downgrade or bankruptcy. Credit quality indicators include, but are not limited to, ratings by credit agencies where available, collection history, collateral, counterparty financial statements and other internal metrics. Utilizing such data, the Registrants have determined three internal grades of credit quality. Internal grade 1 includes financing receivables for counterparties where credit rating agencies have ranked the counterparty as investment grade. To the extent credit ratings are not available, the Registrants utilize other credit quality indicators to determine the level of risk associated with the financing receivable. Internal grade 1 may include financing receivables for counterparties for which credit rating agencies have ranked the counterparty as below investment grade; however, due to favorable information on other credit quality indicators, the Registrants have determined the risk level to be similar to that of an investment grade counterparty. Internal grade 2 includes financing receivables for counterparties with limited credit information and those with a higher risk profile based upon credit quality indicators. Internal grade 3 reflects financing receivables for which the counterparties have the greatest level of risk, including those in bankruptcy status. The following represents the Registrants' financing receivables by year of origination, classified by internal grade of credit risk. The related credit quality indicators and risk ratings utilized to develop the internal grades have been updated through September 30, 2021. DTE Energy DTE Electric Year of Origination 2021 2020 2019 and Prior Total 2021 and Prior (In millions) Notes receivable Internal grade 1 $ — $ — $ 19 $ 19 $ 14 Internal grade 2 2 100 21 123 3 Internal grade 3 — — — — — Total notes receivable (a) $ 2 $ 100 $ 40 $ 142 $ 17 Net investment in leases Net investment in leases, internal grade 1 $ — $ 2 $ 39 $ 41 $ — Net investment in leases, internal grade 2 — 159 1 160 — Total net investment in leases (a) $ — $ 161 $ 40 $ 201 $ — _______________________________________ (a) For DTE Energy, included in Current Assets — Other and Other Assets — Notes Receivable on the Consolidated Statements of Financial Position. For DTE Electric, included in Current Assets — Other on the Consolidated Statements of Financial Position. The allowance for doubtful accounts on accounts receivable for the utility entities is generally calculated using an 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 and future 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 generally 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 non-utility businesses and other receivables for both utility and non-utility businesses is generally calculated based on specific review of probable future collections based on receivable balances generally in excess of 30 days. Existing and future economic conditions, customer trends and other factors are also considered. Receivables are written off on a specific identification basis and determined based upon the specific circumstances of the associated receivable. Notes receivable for DTE Energy are primarily comprised of finance lease receivables and loans that are included in Notes Receivable and Other current assets on DTE Energy's Consolidated Statements of Financial Position. Notes receivable 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. 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 including existing and future economic conditions. Cash payments received on nonaccrual status notes receivable, that do not bring the account contractually current, are first applied to the contractually owed past due interest, with any remainder applied to principal. Accrual of interest is generally resumed when the note receivable becomes contractually current. The following tables present a roll-forward of the activity for the Registrants' financing receivables credit loss reserves: DTE Energy DTE Electric Trade accounts receivable Other receivables Total Trade and other accounts receivable (In millions) Beginning reserve balance, January 1, 2021 $ 101 $ 3 $ 104 $ 57 Current period provision 41 1 42 27 Write-offs charged against allowance (92) (1) (93) (58) Recoveries of amounts previously written off 49 — 49 29 Ending reserve balance, September 30, 2021 $ 99 $ 3 $ 102 $ 55 DTE Energy DTE Electric Trade accounts receivable Other receivables Total Trade and other accounts receivable (In millions) Beginning reserve balance, January 1, 2020 (a) $ 79 $ 4 $ 83 $ 46 Current period provision 102 3 105 61 Write-offs charged against allowance (130) (4) (134) (80) Recoveries of amounts previously written off 50 — 50 30 Ending reserve balance, December 31, 2020 $ 101 $ 3 $ 104 $ 57 _______________________________________ (a) DTE Energy Trade accounts receivable beginning reserve balance excludes $8 million related to the discontinued operations of DT Midstream. Prospective activity includes only the continuing operations of DTE Energy. Uncollectible expense for the Registrants is primarily comprised of the current period provision for allowance for doubtful accounts and is summarized as follows: Three Months Ended September 30, Nine Months Ended September 30, 2021 2020 2021 2020 (In millions) DTE Energy $ 7 $ 22 $ 42 $ 72 DTE Electric 10 16 26 42 There are no material amounts of past due financing receivables for the Registrants as of September 30, 2021.

New Accounting Pronouncements

New Accounting Pronouncements	9 Months Ended
New Accounting Pronouncements	Sep. 30, 2021
Accounting Standards Update and Change in Accounting Principle [Abstract]
New Accounting Pronouncements	NEW ACCOUNTING PRONOUNCEMENTS Recently Adopted Pronouncements In December 2019, the FASB issued ASU No. 2019-12, Income Taxes (Topic 740) - Simplifying the Accounting for Income Taxes . The amendments in this update simplify the accounting for income taxes by removing certain exceptions, and clarifying certain requirements regarding franchise taxes, goodwill, consolidated tax expenses, and annual effective tax rate calculations. The Registrants adopted the ASU effective January 1, 2021 using the modified retrospective and prospective approaches, where applicable. The adoption of the ASU did not have a significant impact on the Registrants' Consolidated Financial Statements. In August 2020, the FASB issued ASU No. 2020-06, Debt - Debt with Conversion and Other Options (Subtopic 470-20) and Derivatives and Hedging - Contracts in Entity's Own Equity (Subtopic 815-40): Accounting for Convertible Instruments and Contracts in an Entity's Own Equity. The amendments in this update simplify the accounting for certain financial instruments with characteristics of liabilities and equity, including convertible instruments and contracts indexed to and potentially settled in an entity's own equity. The Registrants adopted the ASU effective January 1, 2021 using the modified retrospective approach. The adoption of the ASU did not have a significant impact on the Registrants' Consolidated Financial Statements. Recently Issued Pronouncements In March 2020, the FASB issued ASU No. 2020-04, Reference Rate Reform (Topic 848) - Facilitation of the Effects of Reference Rate Reform on Financial Reporting, as amended . The amendments in this update provide optional expedients and exceptions for applying GAAP to contract modifications and hedging relationships, subject to meeting certain criteria, that reference LIBOR or another reference rate expected to be discontinued. The guidance can be applied prospectively from any date beginning March 12, 2020 through December 31, 2022. The optional relief is temporary and cannot be applied to contract modifications and hedging relationships entered into or evaluated after December 31, 2022. The Registrants presently have various contracts that reference LIBOR and are assessing how this standard may be applied to specific contract modifications. In July 2021, the FASB issued ASU No. 2021-05, Leases (Topic 842): Lessors – Certain Leases with Variable Lease Payments.

Dispositions and Impairments

Dispositions and Impairments	9 Months Ended
Dispositions and Impairments	Sep. 30, 2021
Discontinued Operations and Disposal Groups [Abstract]
Dispositions and Impairments	DISPOSITIONS AND IMPAIRMENTS Separation of DT Midstream On October 27, 2020, DTE Energy announced that its Board of Directors had authorized management to pursue a plan to spin-off its natural gas pipeline, storage and gathering non-utility business. On July 1, 2021, DTE Energy completed the separation of the new company, DT Midstream, through the distribution of 96,732,466 shares of DT Midstream common stock to DTE Energy shareholders. The distribution reflected 100% of the outstanding common stock of DT Midstream as of 5:00 p.m. ET on June 18, 2021 (the “record date”). DTE Energy shareholders received one share of DT Midstream common stock for every two shares of DTE Energy common stock held at the close of business on the record date, with certain shareholders receiving cash in lieu of fractional shares of DT Midstream common stock. For U.S. federal income tax purposes, DTE Energy’s U.S. shareholders generally should not recognize gain or loss as a result of the distribution of DT Midstream stock, except with respect to cash received in lieu of fractional shares. In June 2021, in order to facilitate the separation and settle intercompany balances with DTE Energy, DT Midstream issued long-term debt in the form of $2.1 billion senior notes and a $1.0 billion term loan. Using the debt proceeds, net of discount and issuance costs of $53 million, DT Midstream made the following cash payments: • Settled Short-term borrowings due to DTE Energy as of June 30, 2021 of $2,537 million • Settled affiliate Accounts Receivable due from DTE Energy and affiliate Accounts payable due to DTE Energy as of June 30, 2021 for net cash paid to DTE Energy of $9 million • Provided a one-time special dividend to DTE Energy of $501 million These payments eliminated in consolidation and had no direct impact on DTE Energy’s Consolidated Financial Statements of Financial Position. During July and August 2021, DTE Energy used the proceeds received from DT Midstream to optionally redeem $2.6 billion of long-term debt. Refer to Note 10 to the Consolidated Financial Statements, “Long-term Debt,” for additional information. Continuing Involvement Following the separation on July 1, 2021, DT Midstream became an independent public company listed under the symbol “DTM” on the New York Stock Exchange (NYSE) and DTE Energy no longer retains any ownership in DT Midstream. In order to govern the ongoing relationships between DT Midstream and DTE Energy after the separation and to facilitate an orderly transition, the parties entered into a series of agreements including the following: • Separation and Distribution Agreement – sets forth the principal actions to be taken in connection with the separation, including the transfer of assets and assumption of liabilities, among others, and sets forth other agreements governing aspects of the relationship between DTE Energy and DT Midstream • Transition Services Agreement – allows for DTE Energy to provide DT Midstream with specified services for a limited time and no longer than 24 months following the separation, with related costs to be paid by DT Midstream. Services include support for gas operations, information technology, accounting, tax, legal, human resources, and various other administrative services • Tax Matters Agreement – governs the respective rights, responsibilities and obligations of DTE Energy and DT Midstream after the separation with respect to all tax matters • Employee Matters Agreement – addresses certain employment, compensation and benefits matters, including the allocation and treatment of certain assets and liabilities relating to DT Midstream employees In addition, DTE Energy and its subsidiaries have various commercial agreements that will continue after the separation. These agreements include certain pipeline, gathering, and storage services and operating and maintenance agreements, and are not considered material to the Consolidated Financial Statements. Discontinued Operations The table below reflects the financial results of DT Midstream that have been reclassified from continuing operations and included in discontinued operations within the Consolidated Statements of Operations. These results include the impact of tax-related adjustments and all transaction costs related to the separation. General corporate overhead costs have been excluded and no portion of corporate interest costs were allocated to discontinued operations. Three Months Ended September 30, Nine Months Ended September 30, 2021 2020 2021 2020 (In millions) Operating Revenues — Non-utility operations $ — $ 204 $ 405 $ 546 Operating Expenses Cost of gas and other — non-utility — 6 15 14 Operation and maintenance (a) 30 32 124 80 Depreciation and amortization — 38 82 110 Taxes other than income — 3 13 12 Asset (gains) losses and impairments, net — (4) 17 (4) 30 75 251 212 Operating Income (Loss) (30) 129 154 334 Other (Income) and Deductions Interest expense — 29 50 82 Interest income — (4) (4) (6) Other income — (45) (62) (98) — (20) (16) (22) Income (Loss) from Discontinued Operations Before Income Taxes (30) 149 170 356 Income Tax Expense 3 42 58 99 Income (Loss) from Discontinued Operations, Net of Taxes (33) 107 112 257 Less: Net Income Attributable to Noncontrolling Interests — 3 6 8 Net Income (Loss) from Discontinued Operations $ (33) $ 104 $ 106 $ 249 _______________________________________ (a) Includes separation transaction costs of $30 million and $59 million for the three and nine months ended September 30, 2021, respectively, for various legal, accounting and other professional services fees. There were no costs incurred in the comparable prior year periods. Total transaction costs of $67 million have been incurred since October 2020. The table below reflects the major assets and liabilities that were transferred to DT Midstream and presented as discontinued operations in the Consolidated Statements of Financial Position as of December 31, 2020. December 31, 2020 (In millions) Total Assets of Discontinued Operations Cash $ 42 Accounts receivable 126 Inventories 8 Other 44 Current assets of DT Midstream 220 Less: Previously affiliated amounts eliminated at DTE Energy 3 Current assets of discontinued operations for DTE Energy 217 Investments in equity method investees 1,691 Net property, plant, and equipment 3,470 Goodwill 473 Intangible assets 2,140 Notes receivable 19 Operating lease right-of-use assets 45 Other 21 Noncurrent assets of discontinued operations for DTE Energy 7,859 Total Assets of Discontinued Operations for DTE Energy $ 8,076 Total Liabilities of Discontinued Operations Accounts payable $ 39 Operating lease liabilities 17 Short-term borrowings due to DTE Energy (a) 2,913 Other 53 Current liabilities of DT Midstream 3,022 Less: Previously affiliated amounts eliminated at DTE Energy 2,923 Current liabilities of discontinued operations for DTE Energy 99 Deferred income taxes 753 Asset retirement obligations 10 Operating lease liabilities 28 Other 45 Noncurrent liabilities of discontinued operations for DTE Energy 836 Total Liabilities of Discontinued Operations for DTE Energy $ 935 ______________________________________ (a) Short-term borrowings due to DTE Energy resulted in an intercompany note receivable in the Corporate and Other segment at December 31, 2020. The settlement of these borrowings in June 2021 and use of proceeds to redeem DTE Energy long-term debt in the third quarter 2021 has reduced the Total Assets of the Corporate and Other segment in the current period. Other changes in DTE Energy's Total Assets due to the separation of DT Midstream primarily relate to the elimination of Gas Storage and Pipelines segment assets in 2021. There were no assets or liabilities from discontinued operations as of September 30, 2021. DT Midstream had net assets of $4.0 billion that separated on July 1, 2021 that resulted in a reduction to DTE Energy's equity during the third quarter. Refer to the Separation of DT Midstream line within DTE Energy's Consolidated Statements of Changes in Equity for further details. The following table is a summary of significant non-cash items, capital expenditures, and significant financing activities of discontinued operations included in DTE Energy's Consolidated Statements of Cash Flows: Nine Months Ended September 30, 2021 2020 (In millions) Operating Activities Depreciation and amortization $ 82 $ 110 Deferred income taxes 57 95 Equity earnings of equity method investees (59) (75) Asset (gains) losses and impairments, net 19 (4) Investing Activities Plant and equipment expenditures — non-utility $ (60) $ (440) Financing Activities Acquisition related deferred payment, excluding accretion $ — $ (380) DTE Vantage Segment Impairment DTE Vantage owns a pulverized coal facility located at DTE Electric’s River Rouge power plant. The facility provides pulverized coal to a steel industry customer through a supply agreement expiring in 2028. The River Rouge plant provides operation and maintenance services to the facility through an agreement which also expires in 2028. During the second quarter 2021, DTE Electric retired the River Rouge plant and provided an early termination notice of the operation and maintenance services agreement with the pulverized coal facility. The termination would be effective December 31, 2021, at which point DTE Vantage expects to cease operations at the facility. In connection with these events, DTE Energy performed an impairment analysis of the pulverized coal facility long-lived assets in accordance with ASC 360, Property, Plant and Equipment . Based on its undiscounted cash flow projections, DTE Energy determined that the carrying value of the pulverized coal facility asset group is not recoverable. As a result, DTE Energy recorded a non-cash impairment charge of $27 million, which is included in Asset (gains) losses and impairments, net on DTE Energy’s Consolidated Statements of Operations for the nine months ended September 30, 2021. The charge included $18 million to fully impair the long-lived assets recorded to Property, plant and equipment and a $9 million write-down of Other noncurrent assets to fair value. Fair value of the assets was determined using an income approach, which utilized assumptions including management’s best estimates of the expected future cash flows, the estimated useful life of the asset group and discount rate. There were no other adjustments deemed necessary as of September 30, 2021 related to the closure of the facility. DTE Energy is currently monitoring contract negotiations with the steel industry customer to determine any future impacts. An estimate of such impacts cannot be determined at this time as alternatives are currently being evaluated; however, the likelihood of any impact being material to DTE Energy’s Consolidated Financial Statements is remote.

Revenue

Revenue	9 Months Ended
Revenue	Sep. 30, 2021
Revenue from Contract with Customer [Abstract]
Revenue	REVENUE Disaggregation of Revenue The following is a summary of revenues disaggregated by segment for DTE Energy: Three Months Ended September 30, Nine Months Ended September 30, 2021 2020 2021 2020 (In millions) Electric (a) Residential $ 885 $ 900 $ 2,262 $ 2,169 Commercial 533 498 1,452 1,313 Industrial 167 157 473 434 Other (b) 117 138 290 305 Total Electric operating revenues $ 1,702 $ 1,693 $ 4,477 $ 4,221 Gas Gas sales $ 95 $ 92 $ 726 $ 655 End User Transportation 38 34 171 154 Intermediate Transportation 16 15 59 57 Other (b) 44 32 114 98 Total Gas operating revenues $ 193 $ 173 $ 1,070 $ 964 Other segment operating revenues DTE Vantage $ 372 $ 324 $ 1,132 $ 850 Energy Trading $ 1,602 $ 1,061 $ 4,208 $ 2,714 _______________________________________ (a) Revenues generally represent those of DTE Electric, except $2 million and $3 million of Other revenues related to DTE Sustainable Generation for the three months ended September 30, 2021 and 2020, respectively, and $9 million and $10 million for the nine months ended September 30, 2021 and 2020, respectively. (b) Includes revenue adjustments related to various regulatory mechanisms. Revenues included the following which were outside the scope of Topic 606: Three Months Ended September 30, Nine Months Ended September 30, 2021 2020 2021 2020 (In millions) Electric — Other revenues $ 6 $ 8 $ 14 $ 18 Gas — Alternative Revenue Programs — — — 2 Gas — Other revenues 1 2 5 7 DTE Vantage — Leases 26 26 70 74 Energy Trading — Derivatives 1,324 731 3,377 1,835 Deferred Revenue The following is a summary of deferred revenue activity: DTE Energy (In millions) Beginning Balance, January 1, 2021 (a) $ 65 Increases due to cash received or receivable, excluding amounts recognized as revenue during the period 79 Revenue recognized that was included in the deferred revenue balance at the beginning of the period (19) Ending Balance, September 30, 2021 $ 125 _______________________________________ (a) Excludes $22 million of deferred revenue related to the discontinued operations of DT Midstream. Prospective activity includes only the continuing operations of DTE Energy. The deferred revenues at DTE Energy generally represent amounts paid by or receivable from customers for which the associated performance obligation has not yet been satisfied. Deferred revenues include amounts associated with REC performance obligations under certain wholesale full requirements power contracts. Deferred revenues associated with RECs are recognized as revenue when control of the RECs has transferred. Other performance obligations associated with deferred revenues include providing products and services related to customer prepayments. Deferred revenues associated with these products and services are recognized when control has transferred to the customer. The following table represents deferred revenue amounts for DTE Energy that are expected to be recognized as revenue in future periods: DTE Energy (In millions) 2021 $ 72 2022 50 2023 1 2024 1 2025 — 2026 and thereafter 1 $ 125 Transaction Price Allocated to the Remaining Performance Obligations In accordance with optional exemptions available under Topic 606, the Registrants did not disclose the value of unsatisfied performance obligations for (1) contracts with an original expected length of one year or less, (2) with the exception of fixed consideration, contracts for which revenue is recognized at the amount to which the Registrants have the right to invoice for goods provided and services performed, and (3) contracts for which variable consideration relates entirely to an unsatisfied performance obligation. Such contracts consist of varying types of performance obligations across the segments, including the supply and delivery of energy related products and services. Contracts with variable volumes and/or variable pricing, including those with pricing provisions tied to a consumer price or other index, have also been excluded as the related consideration under the contract is variable at inception of the contract. Contract lengths vary from cancellable to multi-year. The Registrants expect to recognize revenue for the following amounts related to fixed consideration associated with remaining performance obligations in each of the future periods noted: DTE Energy DTE Electric (In millions) 2021 $ 41 $ 2 2022 308 8 2023 264 7 2024 159 7 2025 80 1 2026 and thereafter 421 — $ 1,273 $ 25

Regulatory Matters

Regulatory Matters	9 Months Ended
Regulatory Matters	Sep. 30, 2021
Public Utilities, General Disclosures [Abstract]
Regulatory Matters	REGULATORY MATTERS 2020-2021 Accounting Applications On July 9, 2020, the MPSC approved DTE Electric's request to accelerate amortization of the portion of its refundable federal income taxes regulatory liability related to non-plant accumulated deferred income tax balances that resulted from the TCJA. DTE Electric was authorized to increase amortization by $102 million beginning in May 2021, which would fully amortize this portion of the liability by the end of 2021 instead of April 2033. The accelerated amortization would not impact customer rates and would allow DTE Electric to defer its next rate case filing previously set for July 2020 to March 2021. On February 26, 2021, DTE Electric filed an additional application requesting a delay in the accelerated amortization approved in the 2020 application. DTE Electric requested delaying the start of amortization from May 2021 to December 1, 2021, which would fully amortize these balances by the end of 2022 and allow DTE Electric to further defer its next rate case filing. The accounting application was approved by the MPSC on April 8, 2021. On August 31, 2021, DTE Electric filed an accounting application with the MPSC requesting approval of a one-time voluntary refund of $70 million collected in 2021 associated with the unexpected customer usage patterns due to the COVID-19 pandemic. This refund would be administered by investing in additional tree trimming without seeking future cost recovery. Such efforts would serve to improve customer reliability without impacting rates, thus providing an affordability benefit to customers. These investments would be incremental to the Tree Trim Surge expenses previously authorized by the MPSC. DTE Electric anticipates receiving an order by the end of 2021. If approved by the end of the year, a regulatory liability will be recognized at that time. The regulatory liability would be reduced as the additional tree trim expenses are incurred during the remainder of 2021 through 2023. If the full $70 million is not spent by the end of 2023, DTE Electric would provide refunds to customers via bill credits for any shortage. 2021 Securitization Filing On March 26, 2021, DTE Electric filed an application requesting a financing order approving the securitization of $184 million of qualified costs related to the net book value of the River Rouge generation plant and tree trimming surge program costs. The filing requested collection of these qualifying costs from DTE Electric's customers. A final MPSC order was issued on June 23, 2021 authorizing DTE Electric to proceed with the issuance of securitization bonds for qualified costs of up to $236 million, increased for the inclusion of deferred income taxes. The order authorized customer charges for the timely recovery of the amount securitized and other ongoing qualified costs. Securitization is expected in the first quarter 2022. 2021 Gas Rate Case Filing DTE Gas filed a rate case with the MPSC on February 12, 2021 requesting an increase in base rates of $195 million based on a projected twelve-month period ending December 31, 2022. The requested increase in base rates is primarily due to an increase in net plant resulting from infrastructure investments and operating and maintenance expenses. The rate filing also requested an increase in return on equity from 9.9% to 10.25% and includes projected changes in sales and working capital. A final MPSC order in this case is expected by December 2021.

Common Stock and Earnings Per S

Common Stock and Earnings Per Share	9 Months Ended
Common Stock and Earnings Per Share	Sep. 30, 2021
Earnings Per Share [Abstract]
Common Stock and Earnings Per Share	COMMON STOCK AND EARNINGS PER SHARE Earnings per Share Basic earnings per share is calculated by dividing net income, adjusted for income allocated to participating securities, by the weighted average number of common shares outstanding during the period. Diluted earnings per share reflect the dilution that would occur if any potentially dilutive instruments were exercised or converted into common shares. DTE Energy’s participating securities are restricted shares under the stock incentive program that contain rights to receive non-forfeitable dividends. Equity units and performance shares do not receive cash dividends; as such, these awards are not considered participating securities. The following is a reconciliation of DTE Energy's basic and diluted income per share calculation: Three Months Ended September 30, Nine Months Ended September 30, 2021 2020 2021 2020 (In millions, except per share amounts) Basic Earnings per Share Net Income attributable to DTE Energy — continuing operations $ 58 $ 372 $ 495 $ 844 Less: Allocation of earnings to net restricted stock awards — 1 1 2 $ 58 $ 371 $ 494 $ 842 Net Income (Loss) attributable to DTE Energy — discontinued operations (33) 104 106 249 Net income available to common shareholders — basic $ 25 $ 475 $ 600 $ 1,091 Average number of common shares outstanding — basic 193 193 193 192 Income from continuing operations $ 0.30 $ 1.93 $ 2.55 $ 4.37 Income (loss) from discontinued operations (0.17) 0.54 0.55 1.30 Basic Earnings per Common Share $ 0.13 $ 2.47 $ 3.10 $ 5.67 Diluted Earnings per Share Net Income attributable to DTE Energy — continuing operations $ 58 $ 372 $ 495 $ 844 Less: Allocation of earnings to net restricted stock awards — 1 1 2 $ 58 $ 371 $ 494 $ 842 Net Income (Loss) attributable to DTE Energy — discontinued operations (33) 104 106 249 Net income available to common shareholders — diluted $ 25 $ 475 $ 600 $ 1,091 Average number of common shares outstanding — basic 193 193 193 192 Average dilutive equity units, performance share awards, and stock options 1 — 1 1 Average number of common shares outstanding — diluted 194 193 194 193 Income from continuing operations $ 0.30 $ 1.92 $ 2.55 $ 4.37 Income (loss) from discontinued operations (0.17) 0.54 0.55 1.29 Diluted Earnings per Common Share (a) $ 0.13 $ 2.46 $ 3.10 $ 5.66 _______________________________________ (a) Equity Units excluded from the calculation of diluted EPS were approximately 11.1 million and 10.3 million for the three months ended September 30, 2021 and 2020, respectively, and 11.5 million and 10.3 million for the nine months ended September 30, 2021 and 2020, respectively, as the dilutive stock price threshold was not met. Stock Purchase Contract Adjustments In December 2019, DTE Energy closed on the purchase of midstream natural gas assets. The acquisition was financed through the issuance of Senior Notes, common stock, and $1.3 billion of Equity Units. Each Equity Unit has a stated amount of $50 and was initially issued in the form of a Corporate Unit, comprised of (i) a forward purchase contract to buy DTE Energy common stock (stock purchase contract) and (ii) a 1/20 undivided beneficial ownership interest in a $1,000 principal amount of DTE Energy’s 2019 Series F 2.25% RSNs due 2025. The stock purchase contract obligates the holder to purchase from DTE Energy on the settlement date, November 1, 2022, for a price of $50 per stock purchase contract, a certain number of shares of DTE Energy’s common stock. As a result of the spin-off of DT Midstream in July 2021, there was a change in the settlement rates in the stock purchase contract to reflect the dividend of DT Midstream stock to DTE Energy shareholders. As adjusted for this change, anti-dilution adjustments to date, and subject to future anti-dilution adjustments, the following number of shares must be purchased: • if the AMV of DTE Energy’s common stock, which is the average volume-weighted average price of DTE Energy’s common stock for the trading days during the 20 consecutive scheduled trading day period ending on the third scheduled trading day immediately preceding the stock purchase contract settlement date, is equal to or greater than $133.08, 0.3757 shares of common stock; • if the AMV is less than $133.08 but greater than $106.50, a number of shares of common stock equal to $50 divided by the AMV; and • if the AMV is less than or equal to $106.50, 0.4695 shares of common stock. The present value of future contract adjustment payments of $150 million was initially recorded as a reduction of shareholders’ equity, offset by the stock purchase contract liability. The stock purchase contract liability was not impacted by the change in settlement rates and a liability of $64 million remains included in Current Liabilities — Other and Other Liabilities — Other on DTE Energy’s Consolidated Statements of Financial Position as of September 30, 2021. DTE Energy will continue issuing quarterly payments through the settlement date of November 1, 2022. The treasury stock method is used to compute diluted EPS for the stock purchase contract. Under the treasury stock method, the stock purchase contract will only have a dilutive effect when the settlement rate is based on the market value of DTE’s common stock that is greater than $133.08 (the threshold appreciation price). At September 30, 2021, the stock purchase price contract was anti-dilutive and, therefore, not included in the computation of diluted earnings per share. Until settlement of the stock purchase contracts, the shares of stock underlying each contract are not outstanding. Under the terms of the stock purchase contracts, assuming no anti-dilution or other adjustments, DTE Energy will issue between 9.8 million and 12.2 million shares of its common stock in November 2022. A total of 13 million shares of DTE Energy’s common stock have been reserved for issuance in connection with the stock purchase contracts.

Fair Value

Fair Value	9 Months Ended
Fair Value	Sep. 30, 2021
Fair Value Disclosures [Abstract]
Fair Value	FAIR VALUE Fair value is defined as the price that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date in a principal or most advantageous market. Fair value is a market-based measurement that is determined based on inputs, which refer broadly to assumptions that market participants use in pricing assets or liabilities. These inputs can be readily observable, market corroborated, or generally unobservable inputs. The Registrants make certain assumptions they believe that market participants would use in pricing assets or liabilities, including assumptions about risk, and the risks inherent in the inputs to valuation techniques. Credit risk of the Registrants and their counterparties is incorporated in the valuation of assets and liabilities through the use of credit reserves, the impact of which was immaterial at September 30, 2021 and December 31, 2020. The Registrants believe they use valuation techniques that maximize the use of observable market-based inputs and minimize the use of unobservable inputs. A fair value hierarchy has been established that prioritizes the inputs to valuation techniques used to measure fair value in three broad levels. The fair value hierarchy gives the highest priority to quoted prices (unadjusted) in active markets for identical assets or liabilities (Level 1) and the lowest priority to unobservable inputs (Level 3). In some cases, the inputs used to measure fair value might fall in different levels of the fair value hierarchy. All assets and liabilities are required to be classified in their entirety based on the lowest level of input that is significant to the fair value measurement in its entirety. Assessing the significance of a particular input may require judgment considering factors specific to the asset or liability and may affect the valuation of the asset or liability and its placement within the fair value hierarchy. The Registrants classify fair value balances based on the fair value hierarchy defined as follows: • Level 1 — Consists of unadjusted quoted prices in active markets for identical assets or liabilities that the Registrants have the ability to access as of the reporting date. • Level 2 — Consists of inputs other than quoted prices included within Level 1 that are directly observable for the asset or liability or indirectly observable through corroboration with observable market data. • Level 3 — Consists of unobservable inputs for assets or liabilities whose fair value is estimated based on internally developed models or methodologies using inputs that are generally less readily observable and supported by little, if any, market activity at the measurement date. Unobservable inputs are developed based on the best available information and subject to cost-benefit constraints. The following table presents assets and liabilities for DTE Energy measured and recorded at fair value on a recurring basis: September 30, 2021 December 31, 2020 Level Level Level Other (a) Netting (b) Net Balance Level Level Level Other (a) Netting (b) Net Balance (In millions) Assets Cash equivalents (c) $ 9 $ — $ — $ — $ — $ 9 $ 438 $ — $ — $ — $ — $ 438 Nuclear decommissioning trusts Equity securities 944 — — 196 — 1,140 947 — — 222 — 1,169 Fixed income securities 127 429 — 102 — 658 102 371 — 82 — 555 Private equity and other — — — 175 — 175 — — — 104 — 104 Cash equivalents 34 — — — — 34 27 — — — — 27 Other investments (d) Equity securities 61 — — — — 61 55 — — — — 55 Fixed income securities 7 — — — — 7 8 — — — — 8 Cash equivalents 86 — — — — 86 97 — — — — 97 Derivative assets Commodity contracts (e) Natural gas 579 146 53 — (715) 63 99 74 60 — (156) 77 Electricity — 707 245 — (627) 325 — 128 52 — (120) 60 Environmental & Other — 598 12 — (570) 40 — 150 4 — (135) 19 Total derivative assets 579 1,451 310 — (1,912) 428 99 352 116 — (411) 156 Total $ 1,847 $ 1,880 $ 310 $ 473 $ (1,912) $ 2,598 $ 1,773 $ 723 $ 116 $ 408 $ (411) $ 2,609 Liabilities Derivative liabilities Commodity contracts (e) Natural gas $ (425) $ (297) $ (333) $ — $ 664 $ (391) $ (88) $ (59) $ (76) $ — $ 151 $ (72) Electricity — (576) (340) — 614 (302) — (126) (42) — 125 (43) Environmental & Other — (581) — — 570 (11) — (137) — — 129 (8) Foreign currency exchange contracts — (5) — — — (5) — (5) — — (5) Total $ (425) $ (1,459) $ (673) $ — $ 1,848 $ (709) $ (88) $ (327) $ (118) $ — $ 405 $ (128) Net Assets (Liabilities) at end of period $ 1,422 $ 421 $ (363) $ 473 $ (64) $ 1,889 $ 1,685 $ 396 $ (2) $ 408 $ (6) $ 2,481 Assets Current $ 506 $ 1,183 $ 258 $ — $ (1,591) $ 356 $ 532 $ 260 $ 92 $ — $ (330) $ 554 Noncurrent 1,341 697 52 473 (321) 2,242 1,241 463 24 408 (81) 2,055 Total Assets $ 1,847 $ 1,880 $ 310 $ 473 $ (1,912) $ 2,598 $ 1,773 $ 723 $ 116 $ 408 $ (411) $ 2,609 Liabilities Current $ (409) $ (1,138) $ (464) $ — $ 1,546 $ (465) $ (84) $ (223) $ (79) $ — $ 318 $ (68) Noncurrent (16) (321) (209) — 302 (244) (4) (104) (39) — 87 (60) Total Liabilities $ (425) $ (1,459) $ (673) $ — $ 1,848 $ (709) $ (88) $ (327) $ (118) $ — $ 405 $ (128) Net Assets (Liabilities) at end of period $ 1,422 $ 421 $ (363) $ 473 $ (64) $ 1,889 $ 1,685 $ 396 $ (2) $ 408 $ (6) $ 2,481 _______________________________________ (a) Amounts represent assets valued at NAV as a practical expedient for fair value. (b) Amounts represent the impact of master netting agreements that allow DTE Energy to net gain and loss positions and cash collateral held or placed with the same counterparties. (c) Amounts consisted of $1 million and $2 million of cash equivalents included in Restricted cash on DTE Energy's Consolidated Statements of Financial Position at September 30, 2021 and December 31, 2020, respectively. All other amounts are included in Cash and cash equivalents on the Consolidated Statements of Financial Position. (d) Excludes cash surrender value of life insurance investments. (e) For contracts with a clearing agent, DTE Energy nets all activity across commodities. This can result in some individual commodities having a contra balance. The following table presents assets for DTE Electric measured and recorded at fair value on a recurring basis as of: September 30, 2021 December 31, 2020 Level 1 Level 2 Level 3 Other (a) Net Balance Level 1 Level 2 Level 3 Other (a) Net Balance (In millions) Assets Cash equivalents $ — $ — $ — $ — $ — $ 4 $ — $ — $ — $ 4 Nuclear decommissioning trusts Equity securities 944 — — 196 1,140 947 — — 222 1,169 Fixed income securities 127 429 — 102 658 102 371 — 82 555 Private equity and other — — — 175 175 — — — 104 104 Cash equivalents 34 — — — 34 27 — — — 27 Other investments Equity securities 18 — — — 18 16 — — — 16 Cash equivalents 11 — — — 11 11 — — — 11 Derivative assets — FTRs — — 12 — 12 — — 4 — 4 Total $ 1,134 $ 429 $ 12 $ 473 $ 2,048 $ 1,107 $ 371 $ 4 $ 408 $ 1,890 Assets Current $ — $ — $ 12 $ — $ 12 $ 4 $ — $ 4 $ — $ 8 Noncurrent 1,134 429 — 473 2,036 1,103 371 — 408 1,882 Total Assets $ 1,134 $ 429 $ 12 $ 473 $ 2,048 $ 1,107 $ 371 $ 4 $ 408 $ 1,890 _______________________________________ (a) Amounts represent assets valued at NAV as a practical expedient for fair value. Cash Equivalents Cash equivalents include investments with maturities of three months or less when purchased. The cash equivalents shown in the fair value table are comprised of short-term investments and money market funds. Nuclear Decommissioning Trusts and Other Investments The nuclear decommissioning trusts and other investments hold debt and equity securities directly and indirectly through commingled funds. Exchange-traded debt and equity securities held directly, as well as publicly-traded commingled funds, are valued using quoted market prices in actively traded markets. Non-exchange traded fixed income securities are valued based upon quotations available from brokers or pricing services. Non-publicly traded commingled funds holding exchange-traded equity or debt securities are valued based on stated NAVs. There are no significant restrictions for these funds and investments may be redeemed with 7 to 65 days notice depending on the fund. There is no intention to sell the investment in these commingled funds. Private equity and other assets include a diversified group of funds that are classified as NAV assets. These funds primarily invest in limited partnerships, including private equity, private real estate and private credit. Distributions are received through the liquidation of the underlying fund assets over the life of the funds. There are generally no redemption rights. The limited partner must hold the fund for its life or find a third-party buyer, which may need to be approved by the general partner. The funds are established with varied contractual durations generally in the range of 7 years to 12 years. The fund life can often be extended by several years by the general partner, and further extended with the approval of the limited partners. Unfunded commitments related to these investments totaled $155 million and $183 million as of September 30, 2021 and December 31, 2020, respectively. For pricing the nuclear decommissioning trusts and other investments, 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 source of a given security if the trustee determines that another price source is considered preferable. The Registrants have obtained an understanding of how these prices are derived, including the nature and observability of the inputs used in deriving such prices. Derivative Assets and Liabilities Derivative assets and liabilities are comprised of physical and financial derivative contracts, including futures, forwards, options, and swaps that are both exchange-traded and over-the-counter traded contracts. Various inputs are used to value derivatives depending on the type of contract and availability of market data. Exchange-traded derivative contracts are valued using quoted prices in active markets. The Registrants consider the following criteria in determining whether a market is considered active: frequency in which pricing information is updated, variability in pricing between sources or over time, and the availability of public information. Other derivative contracts are valued based upon a variety of inputs including commodity market prices, broker quotes, interest rates, credit ratings, default rates, market-based seasonality, and basis differential factors. The Registrants monitor the prices that are supplied by brokers and pricing services and may use a supplemental price source or change the primary price source of an index if prices become unavailable or another price source is determined to be more representative of fair value. The Registrants have obtained an understanding of how these prices are derived. Additionally, the Registrants selectively corroborate the fair value of their transactions by comparison of market-based price sources. Mathematical valuation models are used for derivatives for which external market data is not readily observable, such as contracts which extend beyond the actively traded reporting period. The Registrants have established a Risk Management Committee whose responsibilities include directly or indirectly ensuring all valuation methods are applied in accordance with predefined policies. The development and maintenance of the Registrants' forward price curves has been assigned to DTE Energy's Risk Management Department, which is separate and distinct from the trading functions within DTE Energy. The following table presents the fair value reconciliation of Level 3 assets and liabilities measured at fair value on a recurring basis for DTE Energy: Three Months Ended September 30, 2021 Three Months Ended September 30, 2020 Natural Gas Electricity Other Total Natural Gas Electricity Other Total (In millions) Net Assets (Liabilities) as of June 30 $ (181) $ (49) $ 15 $ (215) $ 20 $ 16 $ 10 $ 46 Transfers from Level 3 into Level 2 — — — — (1) — — (1) Total gains (losses) Included in earnings (a) (162) (21) — (183) (80) 37 1 (42) Recorded in Regulatory liabilities — — (1) (1) — — 9 9 Purchases, issuances, and settlements Settlements 63 (25) (2) 36 22 (48) (13) (39) Net Assets (Liabilities) as of September 30 $ (280) $ (95) $ 12 $ (363) $ (39) $ 5 $ 7 $ (27) Total gains (losses) included in Net Income attributed to the change in unrealized gains (losses) related to assets and liabilities held at September 30 (a) $ (109) $ (30) $ (2) $ (141) $ (57) $ 11 $ (1) $ (47) _______________________________________ (a) Amounts are reflected in Operating Revenues — Non-utility operations and Fuel, purchased power, gas, and other — non-utility in DTE Energy's Consolidated Statements of Operations. Nine Months Ended September 30, 2021 Nine Months Ended September 30, 2020 Natural Gas Electricity Other Total Natural Gas Electricity Other Total (In millions) Net Assets (Liabilities) as of December 31 $ (16) $ 10 $ 4 $ (2) $ (15) $ 16 $ 3 $ 4 Transfers from Level 3 into Level 2 — — — — (5) — — (5) Total gains (losses) Included in earnings (a) (356) (5) — (361) (44) 90 (7) 39 Recorded in Regulatory liabilities — — 14 14 — — 21 21 Purchases, issuances, and settlements Settlements 92 (100) (6) (14) 25 (101) (10) (86) Net Assets (Liabilities) as of September 30 $ (280) $ (95) $ 12 $ (363) $ (39) $ 5 $ 7 $ (27) Total gains (losses) included in Net Income attributed to the change in unrealized gains (losses) related to assets and liabilities held at September 30 (a) $ (301) $ (54) $ (17) $ (372) $ (20) $ 53 $ (17) $ 16 Total gains (losses) included in Regulatory liabilities attributed to the change in unrealized gains (losses) related to assets and liabilities held at September 30 $ — $ — $ 12 $ 12 $ — $ — $ 7 $ 7 _______________________________________ (a) Amounts are reflected in Operating Revenues — Non-utility operations and Fuel, purchased power, gas, and other — non-utility in DTE Energy's Consolidated Statements of Operations. The following table presents the fair value reconciliation of Level 3 assets and liabilities measured at fair value on a recurring basis for DTE Electric: Three Months Ended September 30, Nine Months Ended September 30, 2021 2020 2021 2020 (In millions) Net Assets as of beginning of period $ 15 $ 10 $ 4 $ 3 Change in fair value recorded in Regulatory liabilities (1) 9 14 21 Purchases, issuances, and settlements Settlements (2) (12) (6) (17) Net Assets as of September 30 $ 12 $ 7 $ 12 $ 7 Total gains (losses) included in Regulatory liabilities attributed to the change in unrealized gains (losses) related to assets and liabilities held at September 30 $ — $ — $ 12 $ 7 Derivatives are transferred between levels primarily due to changes in the source data used to construct price curves as a result of changes in market liquidity. Transfers in and transfers out are reflected as if they had occurred at the beginning of the period. There were no transfers from or into Level 3 for DTE Electric during the three and nine months ended September 30, 2021 and 2020. The following tables present the unobservable inputs related to DTE Energy's Level 3 assets and liabilities: September 30, 2021 Commodity Contracts Derivative Assets Derivative Liabilities Valuation Techniques Unobservable Input Range Weighted Average (In millions) Natural Gas $ 53 $ (333) Discounted Cash Flow Forward basis price (per MMBtu) $ (1.33) — $ 3.53 /MMBtu $ (0.04) /MMBtu Electricity $ 245 $ (340) Discounted Cash Flow Forward basis price (per MWh) $ (8) — $ 10 /MWh $ (1) /MWh December 31, 2020 Commodity Contracts Derivative Assets Derivative Liabilities Valuation Techniques Unobservable Input Range Weighted Average (In millions) Natural Gas $ 60 $ (76) Discounted Cash Flow Forward basis price (per MMBtu) $ (0.86) — $ 2.50 /MMBtu $ (0.07) /MMBtu Electricity $ 52 $ (42) Discounted Cash Flow Forward basis price (per MWh) $ (9) — $ 6 /MWh $ — /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 weighted average price for unobservable inputs was calculated using the average of forward price curves for natural gas and electricity and the absolute value of monthly volumes. The inputs listed above would have had 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 have resulted in a higher (lower) fair value for long positions, with offsetting impacts to short positions. Fair Value of Financial Instruments The following table presents the carrying amount and fair value of financial instruments for DTE Energy: September 30, 2021 December 31, 2020 Carrying Fair Value Carrying Fair Value Amount Level 1 Level 2 Level 3 Amount Level 1 Level 2 Level 3 (In millions) Notes receivable (a) , excluding lessor finance leases $ 142 $ — $ — $ 142 $ 141 $ — $ — $ 141 Short-term borrowings $ 361 $ — $ 361 $ — $ 38 $ — $ 38 $ — Notes payable (b) $ 5 $ — $ — $ 5 $ 19 $ — $ — $ 19 Long-term debt (c) $ 17,222 $ 2,241 $ 15,486 $ 1,104 $ 19,439 $ 2,547 $ 18,230 $ 1,397 _______________________________________ (a) Current portion included in Current Assets — Other on DTE Energy's Consolidated Statements of Financial Position. (b) Included in Current Liabilities — Other and Other Liabilities — Other on DTE Energy's Consolidated Statements of Financial Position. (c) Includes debt due within one year and excludes finance lease obligations. Carrying value also includes unamortized debt discounts and issuance costs. The following table presents the carrying amount and fair value of financial instruments for DTE Electric: September 30, 2021 December 31, 2020 Carrying Fair Value Carrying Fair Value Amount Level 1 Level 2 Level 3 Amount Level 1 Level 2 Level 3 (In millions) Notes receivable (a) $ 17 $ — $ — $ 17 $ 16 $ — $ — $ 16 Short-term borrowings — affiliates $ 32 $ — $ — $ 32 $ 101 $ — $ — $ 101 Short-term borrowings — other $ 159 $ — $ 159 $ — $ — $ — $ — $ — Notes payable (b) $ 4 $ — $ — $ 4 $ 17 $ — $ — $ 17 Long-term debt (c) $ 8,906 $ — $ 9,952 $ 150 $ 8,236 $ — $ 9,579 $ 379 _______________________________________ (a) Included in Current Assets — Other on DTE Electric's Consolidated Statements of Financial Position. (b) Included in Current Liabilities — Other and Other Liabilities — Other on DTE Electric's Consolidated Statements of Financial Position. (c) Includes debt due within one year and excludes finance lease obligations. Carrying value also includes unamortized debt discounts and issuance costs. For further fair value information on financial and derivative instruments, see Note 9 to the Consolidated Financial Statements, "Financial and Other Derivative Instruments." Nuclear Decommissioning Trust Funds DTE Electric has a legal obligation to decommission its nuclear power plants following the expiration of its operating licenses. This obligation is reflected as an Asset retirement obligation on DTE Electric's 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. The following table summarizes DTE Electric's fair value of the nuclear decommissioning trust fund assets: September 30, 2021 December 31, 2020 (In millions) Fermi 2 $ 1,989 $ 1,841 Fermi 1 3 3 Low-level radioactive waste 15 11 $ 2,007 $ 1,855 The costs of securities sold are determined on the basis of specific identification. The following table sets forth DTE Electric's gains and losses and proceeds from the sale of securities by the nuclear decommissioning trust funds: Three Months Ended September 30, Nine Months Ended September 30, 2021 2020 2021 2020 (In millions) Realized gains $ 21 $ 38 $ 80 $ 172 Realized losses $ (1) $ (11) $ (9) $ (103) Proceeds from sale of securities $ 217 $ 816 $ 854 $ 2,054 Realized gains and losses from the sale of securities and unrealized gains and losses incurred by the Fermi 2 trust are recorded to Regulatory assets and the Nuclear decommissioning liability. Realized gains and losses from the sale of securities and unrealized gains and losses on the low-level radioactive waste funds are recorded to the Nuclear decommissioning liability. The following table sets forth DTE Electric's fair value and unrealized gains and losses for the nuclear decommissioning trust funds: September 30, 2021 December 31, 2020 Fair Unrealized Unrealized Fair Unrealized Unrealized (In millions) Equity securities $ 1,140 $ 507 $ (8) $ 1,169 $ 481 $ (6) Fixed income securities 658 24 (5) 555 20 (1) Private equity and other 175 41 (2) 104 — — Cash equivalents 34 — — 27 — — $ 2,007 $ 572 $ (15) $ 1,855 $ 501 $ (7) The following table summarizes the fair value of the fixed income securities held in nuclear decommissioning trust funds by contractual maturity: September 30, 2021 (In millions) Due within one year $ 11 Due after one through five years 138 Due after five through ten years 112 Due after ten years 295 $ 556 Fixed income securities held in nuclear decommissioning trust funds include $102 million of non-publicly traded commingled funds that do not have a contractual maturity date. Other Securities At September 30, 2021 and December 31, 2020, the Registrants' securities included in Other investments on the Consolidated Statements of Financial Position were comprised primarily of investments within DTE Energy's rabbi trust. The rabbi trust was established to fund certain non-qualified pension benefits, and therefore changes in market value are recognized in earnings. Gains and losses are allocated from DTE Energy to DTE Electric and are included in Other Income or Other Expense, respectively, in the Registrants' Consolidated Statements of Operations. The following table summarizes the Registrant's gains (losses) related to the trust: Three Months Ended September 30, Nine Months Ended September 30, 2021 2020 2021 2020 (In millions) Gains (losses) related to equity securities $ (1) $ 2 $ 3 $ (4) Gains (losses) related to fixed income securities — — — (3) $ (1) $ 2 $ 3 $ (7)

Financial and Other Derivative

Financial and Other Derivative Instruments	9 Months Ended
Financial and Other Derivative Instruments	Sep. 30, 2021
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Financial and Other Derivative Instruments	FINANCIAL AND OTHER DERIVATIVE INSTRUMENTS The Registrants recognize all derivatives at their fair value as Derivative assets or liabilities on their respective Consolidated Statements of Financial Position unless they qualify for certain scope exceptions, including the normal purchases and normal sales exception. Further, derivatives that qualify and are designated for hedge accounting are classified as either hedges of a forecasted transaction or the variability of cash flows to be received or paid related to a recognized asset or liability (cash flow hedge); or as hedges of the fair value of a recognized asset or liability or of an unrecognized firm commitment (fair value hedge). For cash flow hedges, the derivative gain or loss is deferred in Accumulated other comprehensive income (loss) and later reclassified into earnings when the underlying transaction occurs. For fair value hedges, changes in fair values for the derivative and hedged item are recognized in earnings each period. For derivatives that do not qualify or are not designated for hedge accounting, changes in fair value are recognized in earnings each period. The Registrants' primary market risk exposure is associated with commodity prices, credit, and interest rates. The Registrants have risk management policies to monitor and manage market risks. The Registrants use derivative instruments to manage some of the exposure. DTE Energy uses derivative instruments for trading purposes in its Energy Trading segment. Contracts classified as derivative instruments include electricity, natural gas, oil, certain environmental contracts, forwards, futures, options, swaps, and foreign currency exchange contracts. Items not classified as derivatives include natural gas and environmental inventory, pipeline transportation contracts, certain environmental contracts, and natural gas storage assets. DTE Electric — DTE Electric generates, purchases, distributes, and sells electricity. DTE Electric uses forward contracts to manage changes in the price of electricity and fuel. Substantially all of these contracts meet the normal purchases and normal sales exception and are therefore accounted for under the accrual method. Other derivative contracts are MTM and recoverable through the PSCR mechanism when settled. This results in the deferral of unrealized gains and losses as Regulatory assets or liabilities until realized. DTE Gas — DTE Gas purchases, stores, transports, distributes, and sells natural gas, and buys and sells transportation and storage capacity. DTE Gas has fixed-priced contracts for portions of its expected natural gas supply requirements through March 2024. Substantially all of these contracts meet the normal purchases and normal sales exception and are therefore accounted for under the accrual method. Forward transportation and storage contracts are generally not derivatives and are therefore accounted for under the accrual method. DTE Vantage — This segment manages and operates industrial energy projects, reduced emissions fuel projects, renewable gas recovery, and power generation assets. Primarily fixed-price contracts are used in the marketing and management of the segment assets. These contracts are generally not derivatives and are therefore accounted for under the accrual method. Energy Trading — Commodity Price Risk — Energy Trading markets and trades electricity, natural gas physical products, and energy financial instruments, and provides energy and asset management services utilizing energy commodity derivative instruments. Forwards, futures, options, and swap agreements are used to manage exposure to the risk of market price and volume fluctuations in its operations. These derivatives are accounted for by recording changes in fair value to earnings unless hedge accounting criteria are met. Energy Trading — Foreign Currency Exchange Risk — Energy Trading has foreign currency exchange forward contracts to economically hedge fixed Canadian dollar commitments existing under natural gas and power purchase and sale contracts and natural gas transportation contracts. Energy Trading enters into these contracts to mitigate price volatility with respect to fluctuations of the Canadian dollar relative to the U.S. dollar. These derivatives are accounted for by recording changes in fair value to earnings unless hedge accounting criteria are met. Corporate and Other — Interest Rate Risk — DTE Energy may use interest rate swaps, treasury locks, and other derivatives to hedge the risk associated with interest rate market volatility. Credit Risk — DTE Energy maintains credit policies that significantly minimize overall credit risk. These policies include an evaluation of potential customers’ and counterparties’ financial condition, including the viability of underlying productive assets, credit rating, collateral requirements, or other credit enhancements such as letters of credit or guarantees. DTE Energy generally uses standardized agreements that allow the netting of positive and negative transactions associated with a single counterparty. DTE Energy maintains a provision for credit losses based on factors surrounding the credit risk of its customers, historical trends, and other information. Based on DTE Energy's credit policies and its September 30, 2021 provision for credit losses, DTE Energy’s exposure to counterparty nonperformance is not expected to have a material adverse effect on DTE Energy's Consolidated Financial Statements. Derivative Activities DTE Energy manages its MTM risk on a portfolio basis based upon the delivery period of its contracts and the individual components of the risks within each contract. Accordingly, it records and manages the energy purchase and sale obligations under its contracts in separate components based on the commodity (e.g. electricity or natural gas), the product (e.g. electricity for delivery during peak or off-peak hours), the delivery location (e.g. by region), the risk profile (e.g. forward or option), and the delivery period (e.g. by month and year). The following describes the categories of activities represented by their operating characteristics and key risks: • Asset Optimization — Represents derivative activity associated with assets owned and contracted by DTE Energy, including forward natural gas purchases and sales, natural gas transportation, and storage capacity. Changes in the value of derivatives in this category typically economically offset changes in the value of underlying non-derivative positions, which do not qualify for fair value accounting. The difference in accounting treatment of derivatives in this category and the underlying non-derivative positions can result in significant earnings volatility. • Marketing and Origination — Represents derivative activity transacted by originating substantially hedged positions with wholesale energy marketers, producers, end-users, utilities, retail aggregators, and alternative energy suppliers. • Fundamentals Based Trading — Represents derivative activity transacted with the intent of taking a view, capturing market price changes, or putting capital at risk. This activity is speculative in nature as opposed to hedging an existing exposure. • Other — Includes derivative activity at DTE Electric related to FTRs. Changes in the value of derivative contracts at DTE Electric are recorded as Derivative assets or liabilities, with an offset to Regulatory assets or liabilities as the settlement value of these contracts will be included in the PSCR mechanism when realized. The following table presents the fair value of derivative instruments for DTE Energy: September 30, 2021 December 31, 2020 Derivative Derivative Liabilities Derivative Derivative Liabilities (In millions) Derivatives designated as hedging instruments Foreign currency exchange contracts $ — $ (3) $ — $ (4) Derivatives not designated as hedging instruments Commodity contracts Natural gas $ 778 $ (1,055) $ 233 $ (223) Electricity 952 (916) 180 (168) Environmental & Other 610 (581) 154 (137) Foreign currency exchange contracts — (2) — (1) Total derivatives not designated as hedging instruments $ 2,340 $ (2,554) $ 567 $ (529) Current $ 1,938 $ (2,011) $ 446 $ (386) Noncurrent 402 (546) 121 (147) Total derivatives $ 2,340 $ (2,557) $ 567 $ (533) The following table presents the fair value of derivative instruments for DTE Electric: September 30, 2021 December 31, 2020 (In millions) FTRs — Other current assets $ 12 $ 4 Total derivatives not designated as hedging instruments $ 12 $ 4 Certain of DTE Energy's derivative positions are subject to netting arrangements which provide for offsetting of asset and liability positions as well as related cash collateral. Such netting arrangements generally do not have restrictions. Under such netting arrangements, DTE Energy offsets the fair value of derivative instruments with cash collateral received or paid for those contracts executed with the same counterparty, which reduces DTE Energy's Total Assets and Liabilities. Cash collateral is allocated between the fair value of derivative instruments and customer accounts receivable and payable with the same counterparty on a pro-rata basis to the extent there is exposure. Any cash collateral remaining, after the exposure is netted to zero, is reflected in Accounts receivable and Accounts payable as collateral paid or received, respectively. DTE Energy also provides and receives collateral in the form of letters of credit which can be offset against net Derivative assets and liabilities as well as Accounts receivable and payable. DTE Energy had issued letters of credit of $20 million and $7 million outstanding at September 30, 2021 and December 31, 2020, respectively, which could be used to offset net Derivative liabilities. Letters of credit received from third parties which could be used to offset net Derivative assets were $55 million and $9 million at September 30, 2021 and December 31, 2020, respectively. Such balances of letters of credit are excluded from the tables below and are not netted with the recognized assets and liabilities in DTE Energy's Consolidated Statements of Financial Position. For contracts with certain clearing agents, the fair value of derivative instruments is netted against realized positions with the net balance reflected as either 1) a Derivative asset or liability or 2) an Account receivable or payable. Other than certain clearing agents, Accounts receivable and Accounts payable that are subject to netting arrangements have not been offset against the fair value of Derivative assets and liabilities. The following table presents net cash collateral offsetting arrangements for DTE Energy: September 30, 2021 December 31, 2020 (In millions) Cash collateral netted against Derivative assets $ (122) $ (12) Cash collateral netted against Derivative liabilities 58 6 Cash collateral recorded in Accounts receivable (a) 66 14 Cash collateral recorded in Accounts payable (a) (8) (1) Total net cash collateral posted (received) $ (6) $ 7 _______________________________________ (a) Amounts are recorded net by counterparty. The following table presents the netting offsets of Derivative assets and liabilities for DTE Energy: September 30, 2021 December 31, 2020 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 $ 778 $ (715) $ 63 $ 233 $ (156) $ 77 Electricity 952 (627) 325 180 (120) 60 Environmental & Other 610 (570) 40 154 (135) 19 Total derivative assets $ 2,340 $ (1,912) $ 428 $ 567 $ (411) $ 156 Derivative liabilities Commodity contracts Natural gas $ (1,055) $ 664 $ (391) $ (223) $ 151 $ (72) Electricity (916) 614 (302) (168) 125 (43) Environmental & Other (581) 570 (11) (137) 129 (8) Foreign currency exchange contracts (5) — (5) (5) — (5) Total derivative liabilities $ (2,557) $ 1,848 $ (709) $ (533) $ 405 $ (128) The following table presents the netting offsets of Derivative assets and liabilities showing the reconciliation of derivative instruments to DTE Energy's Consolidated Statements of Financial Position: September 30, 2021 December 31, 2020 Derivative Assets Derivative Liabilities Derivative Assets Derivative Liabilities Current Noncurrent Current Noncurrent Current Noncurrent Current Noncurrent (In millions) Total fair value of derivatives $ 1,938 $ 402 $ (2,011) $ (546) $ 446 $ 121 $ (386) $ (147) Counterparty netting (1,498) (292) 1,498 292 (318) (81) 318 81 Collateral adjustment (93) (29) 48 10 (12) — — 6 Total derivatives as reported $ 347 $ 81 $ (465) $ (244) $ 116 $ 40 $ (68) $ (60) The effect of derivatives not designated as hedging instruments on DTE Energy's Consolidated Statements of Operations is as follows: Location of Gain (Loss) Recognized in Income on Derivatives Gain (Loss) Recognized in Income on Derivatives for the Three Months Ended September 30, Gain (Loss) Recognized in Income on Derivatives for the Nine Months Ended September 30, 2021 2020 2021 2020 (In millions) Commodity contracts Natural gas Operating Revenues — Non-utility operations $ (214) $ (27) $ (371) $ (63) Natural gas Fuel, purchased power, gas, and other — non-utility 63 (51) (16) 28 Electricity Operating Revenues — Non-utility operations 68 33 143 75 Environmental & Other Operating Revenues — Non-utility operations 3 2 (36) (40) Foreign currency exchange contracts Operating Revenues — Non-utility operations 2 (2) (1) — Total $ (78) $ (45) $ (281) $ — Revenues and energy costs related to trading contracts are presented on a net basis in DTE Energy's Consolidated Statements of Operations. Commodity derivatives used for trading purposes, and financial non-trading commodity derivatives, are accounted for using the MTM method with unrealized and realized gains and losses recorded in Operating Revenues — Non-utility operations. Non-trading physical commodity sale and purchase derivative contracts are generally accounted for using the MTM method with unrealized and realized gains and losses for sales recorded in Operating Revenues — Non-utility operations and purchases recorded in Fuel, purchased power, gas, and other — non-utility. The following represents the cumulative gross volume of DTE Energy's derivative contracts outstanding as of September 30, 2021: Commodity Number of Units Natural gas (MMBtu) 2,096,409,912 Electricity (MWh) 29,383,562 Foreign currency exchange ($ CAD) 119,281,865 Renewable Energy Certificates (MWh) 8,387,594 Carbon emissions (Metric Tons) 48,343,793 Various subsidiaries of DTE Energy have entered into contracts which contain ratings triggers and are guaranteed by DTE Energy. These contracts contain provisions which allow the counterparties to require that DTE Energy post cash or letters of credit as collateral in the event that DTE Energy’s credit rating is downgraded below investment grade. Certain of these provisions (known as "hard triggers") state specific circumstances under which DTE Energy can be required to post collateral upon the occurrence of a credit downgrade, while other provisions (known as "soft triggers") are not as specific. For contracts with soft triggers, it is difficult to estimate the amount of collateral which may be requested by counterparties and/or which DTE Energy may ultimately be required to post. The amount of such collateral which could be requested fluctuates based on commodity prices (primarily natural gas, power, environmental, and coal) and the provisions and maturities of the underlying transactions. As of September 30, 2021, DTE Energy's contractual obligation to post collateral in the form of cash or letters of credit in the event of a downgrade to below investment grade, under both hard trigger and soft trigger provisions, was $575 million. As of September 30, 2021, DTE Energy had $2,180 million of derivatives in net liability positions, for which hard triggers exist. There is $52 million of collateral that has been posted against such liabilities, including cash and letters of credit. Associated derivative net asset positions for which contractual offset exists were $1,788 million. The net remaining amount of $340 million is derived from the $575 million noted above.

Long-Term Debt

Long-Term Debt	9 Months Ended
Long-Term Debt	Sep. 30, 2021
Debt Disclosure [Abstract]
Long-Term Debt	LONG-TERM DEBT Debt Issuances In 2021, the following debt was issued: Company Month Type Interest Rate Maturity Date Amount (In millions) DTE Electric March Mortgage bonds (a) 1.90% 2028 $ 575 DTE Electric March Mortgage bonds (a) 3.25% 2051 425 DT Midstream June Senior notes (b) 4.125% 2029 1,100 DT Midstream June Senior notes (b) 4.375% 2031 1,000 DT Midstream June Term loan facility (b) Variable 2028 1,000 $ 4,100 _______________________________________ (a) Bonds were issued as Green Bonds and the proceeds will be used to finance qualified expenditures for solar and wind energy, payments under power purchase agreements for solar and wind energy, and energy optimization programs. (b) Proceeds were used for the repayment of short-term borrowings due to DTE Energy to facilitate the separation of DT Midstream, as well as a one-time special dividend provided to DTE Energy. The debt was transferred to DT Midstream upon its separation on July 1, 2021. Refer to Note 4 to the Consolidated Financial Statements, “Dispositions and Impairments,” for additional information and to the Debt Redemptions section below for DTE Energy's use of the proceeds received from DT Midstream. In September 2021, DTE Electric completed a mandatory remarketing of $82 million of 1.45% Tax-Exempt Revenue Bonds at the same rate of 1.45% until maturity in 2030 and $59 million of 1.45% Tax-Exempt Revenue Bonds at a rate of 1.35% until maturity in 2029. Additionally in September 2021, DTE Gas agreed to issue $60 million of 2.07% First Mortgage Bonds due December 1, 2031 and $95 million of 2.85% First Mortgage Bonds due December 1, 2051 to a group of institutional investors in a private placement transaction. These bonds are expected to close and fund in November 2021. Proceeds will be used for the repayment of short-term borrowings and general corporate purposes, including capital expenditures. Debt Redemptions In 2021, the following debt was redeemed: Company Month Type Interest Rate Maturity Date Amount (In millions) DTE Electric April Mortgage bonds 3.90% 2021 $ 250 DTE Electric May Mortgage bonds 7.00% 2021 33 DTE Energy June Junior subordinated debentures (a) 5.375% 2076 300 DTE Energy July Senior notes 3.30% 2022 300 DTE Energy July Senior notes 2.60% 2022 300 DTE Energy July Senior notes 3.70% 2023 600 DTE Energy July Senior notes 3.85% 2023 135 DTE Energy July Senior notes 3.50% 2024 350 DTE Energy July Senior notes 3.80% 2027 350 DTE Energy July Senior notes 3.40% 2029 21 DTE Energy July Senior notes 6.375% 2033 191 DTE Energy August Senior notes 3.85% 2023 165 DTE Energy August Senior notes 6.375% 2033 209 DTE Electric August Mortgage bonds 6.90% 2021 38 $ 3,242 _______________________________________ (a) Early redemption resulted in a loss on extinguishment of debt of $8 million relating to the write-off of unamortized issuance costs.

Short-Term Credit Arrangements

Short-Term Credit Arrangements and Borrowings	9 Months Ended
Short-Term Credit Arrangements and Borrowings	Sep. 30, 2021
Short-term Debt [Abstract]
Short-Term Credit Arrangements and Borrowings	SHORT-TERM CREDIT ARRANGEMENTS AND BORROWINGS DTE Energy, DTE Electric, and DTE Gas have unsecured revolving credit agreements that can be used for general corporate borrowings, but are intended to provide liquidity support for each of the companies’ commercial paper programs. Borrowings under the revolvers are available at prevailing short-term interest rates. DTE Energy also has other facilities to support letter of credit issuance. The unsecured revolving credit agreements have historically required DTE Energy, DTE Electric, and DTE Gas to maintain a total funded debt to capitalization ratio of no more than 0.65 to 1. In June 2021, DTE Energy amended its total funded debt to capitalization ratio requirement to no more than 0.70 to 1 starting with the third quarter of 2021 and ending December 2022. The amendment was a result of temporary balance sheet impacts resulting from the separation of DT Midstream on July 1, 2021. In the agreements, "total funded debt" means all indebtedness of each respective company and their consolidated subsidiaries, including finance 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 equity of each respective company and their consolidated subsidiaries (excluding pension effects under certain FASB statements), as determined in accordance with accounting principles generally accepted in the United States of America. At September 30, 2021, the total funded debt to total capitalization ratios for DTE Energy, DTE Electric, and DTE Gas were 0.66 to 1, 0.51 to 1, and 0.46 to 1, respectively, and were in compliance with this financial covenant. The availability under these facilities as of September 30, 2021 is shown in the following table: DTE Energy DTE Electric DTE Gas Total (In millions) Unsecured revolving credit facility, expiring April 2025 (a) $ 1,500 $ 500 $ 300 $ 2,300 Unsecured Canadian revolving credit facility, expiring May 2023 87 — — 87 Unsecured letter of credit facility, expiring in February 2023 150 — — 150 Unsecured letter of credit facility, expiring in July 2023 70 — — 70 Unsecured letter of credit facility (b) 50 — — 50 1,857 500 300 2,657 Amounts outstanding at September 30, 2021 Revolver borrowings 74 — — 74 Commercial paper issuances — 159 128 287 Letters of credit 268 — — 268 342 159 128 629 Net availability at September 30, 2021 $ 1,515 $ 341 $ 172 $ 2,028 _______________________________________ (a) Total availability of $102 million expires in April 2024, including $67 million at DTE Energy, $22 million at DTE Electric, and $13 million at DTE Gas. All other availability expires in April 2025. (b) Uncommitted letter of credit facility with automatic renewal provision for each July and therefore no expiration.

Leases

Leases	9 Months Ended
Leases	Sep. 30, 2021
Leases [Abstract]
Leases	LEASES Lessor During the first quarter 2021, DTE Energy completed construction of and began operating certain energy infrastructure assets for a large industrial customer under a long-term agreement, where the assets will transfer to the customer at the end of the contract term in 2040. DTE Energy has accounted for a portion of the agreement as a finance lease arrangement, recognizing an additional net investment of $31 million. The components of DTE Energy’s net investment in finance leases for remaining periods were as follows: DTE Energy September 30, 2021 (In millions) 2021 $ 6 2022 22 2023 22 2024 22 2025 22 2026 and Thereafter 292 Total minimum future lease receipts 386 Residual value of leased pipeline 17 Less unearned income 202 Net investment in finance lease 201 Less current portion 7 $ 194 Interest income recognized under finance leases was $4 million for the three months ended September 30, 2021 and 2020 and $13 million and $12 million for the nine months ended September 30, 2021 and 2020, respectively. DTE Energy’s lease income associated with operating leases, including the line items in which it was included on the Consolidated Statements of Operations, was as follows: Three Months Ended September 30, Nine Months Ended September 30, 2021 2020 2021 2020 (In millions) Fixed payments $ 13 $ 14 $ 42 $ 43 Variable payments 55 43 90 82 $ 68 $ 57 $ 132 $ 125 Operating revenues $ 26 $ 26 $ 70 $ 74 Other income 42 31 62 51 $ 68 $ 57 $ 132 $ 125
Leases	LEASES Lessor During the first quarter 2021, DTE Energy completed construction of and began operating certain energy infrastructure assets for a large industrial customer under a long-term agreement, where the assets will transfer to the customer at the end of the contract term in 2040. DTE Energy has accounted for a portion of the agreement as a finance lease arrangement, recognizing an additional net investment of $31 million. The components of DTE Energy’s net investment in finance leases for remaining periods were as follows: DTE Energy September 30, 2021 (In millions) 2021 $ 6 2022 22 2023 22 2024 22 2025 22 2026 and Thereafter 292 Total minimum future lease receipts 386 Residual value of leased pipeline 17 Less unearned income 202 Net investment in finance lease 201 Less current portion 7 $ 194 Interest income recognized under finance leases was $4 million for the three months ended September 30, 2021 and 2020 and $13 million and $12 million for the nine months ended September 30, 2021 and 2020, respectively. DTE Energy’s lease income associated with operating leases, including the line items in which it was included on the Consolidated Statements of Operations, was as follows: Three Months Ended September 30, Nine Months Ended September 30, 2021 2020 2021 2020 (In millions) Fixed payments $ 13 $ 14 $ 42 $ 43 Variable payments 55 43 90 82 $ 68 $ 57 $ 132 $ 125 Operating revenues $ 26 $ 26 $ 70 $ 74 Other income 42 31 62 51 $ 68 $ 57 $ 132 $ 125
Leases	LEASES Lessor During the first quarter 2021, DTE Energy completed construction of and began operating certain energy infrastructure assets for a large industrial customer under a long-term agreement, where the assets will transfer to the customer at the end of the contract term in 2040. DTE Energy has accounted for a portion of the agreement as a finance lease arrangement, recognizing an additional net investment of $31 million. The components of DTE Energy’s net investment in finance leases for remaining periods were as follows: DTE Energy September 30, 2021 (In millions) 2021 $ 6 2022 22 2023 22 2024 22 2025 22 2026 and Thereafter 292 Total minimum future lease receipts 386 Residual value of leased pipeline 17 Less unearned income 202 Net investment in finance lease 201 Less current portion 7 $ 194 Interest income recognized under finance leases was $4 million for the three months ended September 30, 2021 and 2020 and $13 million and $12 million for the nine months ended September 30, 2021 and 2020, respectively. DTE Energy’s lease income associated with operating leases, including the line items in which it was included on the Consolidated Statements of Operations, was as follows: Three Months Ended September 30, Nine Months Ended September 30, 2021 2020 2021 2020 (In millions) Fixed payments $ 13 $ 14 $ 42 $ 43 Variable payments 55 43 90 82 $ 68 $ 57 $ 132 $ 125 Operating revenues $ 26 $ 26 $ 70 $ 74 Other income 42 31 62 51 $ 68 $ 57 $ 132 $ 125

Commitments and Contingencies

Commitments and Contingencies	9 Months Ended
Commitments and Contingencies	Sep. 30, 2021
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	COMMITMENTS AND CONTINGENCIES Environmental DTE Electric Air — DTE Electric is subject to the EPA ozone and fine particulate transport and acid rain regulations that limit power plant emissions of SO 2 and NO X . The EPA and the State of Michigan have also issued emission reduction regulations relating to ozone, fine particulate, regional haze, mercury, and other air pollution. These rules have led to controls on fossil-fueled power plants to reduce SO 2 , NO X , mercury, and other emissions. Additional rulemakings may occur over the next few years which could require additional controls for SO 2 , NO X , and other hazardous air pollutants. The EPA proposed revised air quality standards for ground level ozone in November 2014 and specifically requested comments on the form and level of the ozone standards. The standards were finalized in October 2015. The State of Michigan recommended to the EPA in October 2016 which areas of the state are not attaining the new standard. On April 30, 2018, the EPA finalized the State of Michigan's recommended marginal non-attainment designation for southeast Michigan. The State is required to develop and implement a plan to address the southeast Michigan ozone non-attainment area by the end of 2021. The Registrants cannot predict the scope and associated financial impact of the State's plan to address the ozone non-attainment area at this time. The EPA has implemented regulatory actions under the Clean Air Act to address emissions of GHGs from the utility sector and other sectors of the economy. Among these actions, in 2015 the EPA finalized performance standards for emissions of carbon dioxide from new and existing fossil-fuel fired EGUs. The performance standards for existing EGUs, known as the EPA Clean Power Plan, were challenged by petitioners and stayed by the U.S. Supreme Court in February 2016 pending final review by the courts. On October 10, 2017, the EPA, under a new administration, proposed to rescind the Clean Power Plan, and in August 2018, the EPA proposed revised emission guidelines for GHGs from existing EGUs. On June 19, 2019, the EPA Administrator officially repealed the Clean Power Plan and finalized its replacement, named the ACE rule. The ACE rule was vacated and remanded back to the EPA in a D.C. Circuit Court decision on January 19, 2021. The next steps taken by the EPA with respect to regulation of GHGs from EGUs is uncertain. Regardless of future rules, DTE Energy remains committed for its electric utility operations to reduce carbon emissions 32% by 2023, 50% by 2028, and 80% by 2040 from 2005 carbon emissions levels, and its goal of net zero emissions for its electric utility operations by 2050. In addition to the GHG standards for existing EGUs, in December 2018, the EPA issued proposed revisions to the carbon dioxide performance standards for new, modified, or reconstructed fossil-fuel fired EGUs. The rule was finalized on January 13, 2021 and immediately challenged. An order vacating the rule was filed by the D.C. Circuit Court of Appeals on April 5, 2021. The carbon standards for new sources are not expected to have a material impact on DTE Electric, since DTE Electric has no plans to build new coal-fired generation and any potential new gas generation will be able to comply with the standards. Pending or future legislation or other regulatory actions could have a material impact on DTE Electric's operations and financial position and the rates charged to its customers. Impacts include expenditures for environmental equipment beyond what is currently planned, financing costs related to additional capital expenditures, the purchase of emission credits from market sources, higher costs of purchased power, and the retirement of facilities where control equipment is not economical. DTE Electric would seek to recover these incremental costs through increased rates charged to its utility customers, as authorized by the MPSC. To comply with air pollution requirements, DTE Electric has spent approximately $2.4 billion. DTE Electric does not anticipate additional capital expenditures for air pollution requirements, subject to the results of future rulemakings. Water — In response to an EPA regulation, DTE Electric was required to examine alternatives for reducing the environmental impacts of the cooling water intake structures at several of its facilities. Based on the results of completed studies and expected future studies, DTE Electric may be required to install technologies to reduce the impacts of the water intake structures. A final rule became effective in October 2014. The final rule requires studies to be completed and submitted as part of the NPDES permit application process to determine the type of technology needed to reduce impacts to fish. DTE Electric has initiated the process of completing the required studies. Final compliance for the installation of any required technology will be determined by the state on a case by case, site specific basis. DTE Electric is currently evaluating the compliance options and working with the State of Michigan on evaluating whether any controls are needed. These evaluations/studies may require modifications to some existing intake structures. It is not possible to quantify the impact of this rule making at this time. Contaminated and Other Sites — Prior to the construction of major interstate natural gas pipelines, gas for heating and other uses was manufactured locally from processes involving coal, coke, or oil. The facilities, which produced gas, have been designated as MGP sites. DTE Electric conducted remedial investigations at contaminated sites, including three former MGP sites. Cleanup of one of the MGP sites is complete, and the site is closed. The investigations have revealed contamination related to the by-products of gas manufacturing at each MGP site. In addition to the MGP sites, DTE Electric is also in the process of cleaning up other contaminated sites, including the area surrounding an ash landfill, electrical distribution substations, electric generating power plants, and underground and above ground 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, 2021 and December 31, 2020, DTE Electric had $13 million and $10 million, respectively, accrued for remediation. These costs are not discounted to their present value. Any change in assumptions, such as remediation techniques, nature and extent of contamination, and regulatory requirements, could impact the estimate of remedial action costs for the sites and affect DTE Electric’s financial position and cash flows. DTE Electric believes the likelihood of a material change to the accrued amount is remote based on current knowledge of the conditions at each site. Coal Combustion Residuals and Effluent Limitations Guidelines — A final EPA rule for the disposal of coal combustion residuals, commonly known as coal ash, became effective in October 2015, and was revised in October 2016, July 2018, September 2020, and November 2020. The rule is based on the continued listing of coal ash as a non-hazardous waste and relies on various self-implementation design and performance standards. DTE Electric owns and operates three permitted engineered coal ash storage facilities to dispose of coal ash from coal-fired power plants and operates a number of smaller impoundments at its power plants subject to certain provisions in the CCR rule. At certain facilities, the rule currently requires ongoing sampling and testing of monitoring wells, compliance with groundwater standards, and the closure of basins at the end of the useful life of the associated power plant. On September 28, 2020, the CCR rule "A Holistic Approach to Closure Part A: Deadline to Initiate Closure and Enhancing Public Access to Information" became effective and established April 11, 2021 as the new deadline for all unlined impoundments (including units previously classified as "clay-lined") to initiate closure. Additionally, the rule amends certain reporting requirements and CCR website requirements. On November 12, 2020, an additional revision to the CCR Rule "A Holistic Approach to Closure Part B: Alternate Demonstration for Unlined Surface Impoundments" was published in the Federal Register that provides a process to determine if certain unlined impoundments consist of an alternative liner system that may be as protective as the current liners specified in the CCR rule, and therefore may continue to operate. DTE Electric has submitted applications to the EPA that support continued use of all impoundments through their active lives. The forced closure date of April 11, 2021 is effectively delayed while the EPA's review has extended beyond this date. At the State level, legislation was signed by the Governor in December 2018 and provides for further regulation of the CCR program in Michigan. Additionally, the bill provides the basis of a CCR program that EGLE has submitted to the EPA for approval to fully regulate the CCR program in Michigan in lieu of a Federal permit program. On April 12, 2017, the EPA granted a petition for reconsideration of the 2015 ELG Rule. The EPA also signed an administrative stay of the 2015 ELG Rule’s compliance deadlines for fly ash transport water, bottom ash transport water, and flue gas desulfurization (FGD) wastewater, among others. On June 6, 2017, the EPA published in the Federal Register a proposed rule (Postponement Rule) to postpone certain applicable deadlines within the 2015 ELG rule. The Postponement Rule was published on September 18, 2017. The Postponement Rule nullified the administrative stay but also extended the earliest compliance deadlines for only FGD wastewater and bottom ash transport water until November 1, 2020 in order for the EPA to propose and finalize a new ruling. On October 13, 2020, the EPA finalized the ELG Reconsideration Rule which revised the regulations from the 2015 ELG rule. The Reconsideration Rule revises requirements for two specific waste streams produced by steam electric power plants: FGD wastewater and bottom ash transport water. The Reconsideration Rule also provides additional compliance opportunities by finalizing low utilization and cessation of coal burning subcategories. The Reconsideration Rule provides new opportunities for DTE Electric to evaluate existing ELG compliance strategies and make any necessary adjustments to ensure full compliance with the ELGs in a cost-effective manner. In October 2020, the EPA published in the Federal Register the final version of the ELG Reconsideration Rule which updates the 2015 ELG Rule. The Reconsideration Rule re-establishes the technology-based effluent limitations guidelines and standards applicable to FGD wastewater and bottom ash transport water. The EPA set the applicability dates for bottom ash transport water and FGD wastewater retrofits to be "as soon as possible" beginning October 13, 2021 and no later than December 31, 2025. Compliance schedules for individual facilities and individual waste streams are determined through issuance of new NPDES permits by the State of Michigan. The State of Michigan has issued an NPDES permit for the Belle River power plant establishing compliance deadlines based on the 2020 Reconsideration Rule. The deadline is December 31, 2025 if DTE Electric chooses to comply by installation of new treatment technologies, or December 31, 2028 if DTE Electric chooses to pursue the cessation of coal as their ELG compliance option. On July 27, 2021, the EPA announced they will revisit some of the compliance requirements that were established in the 2020 Reconsideration Rule and plan to release a new proposed rule in Fall of 2022. The 2020 Reconsideration Rule remains in effect until that time. On October 11, 2021, in consideration of the deadlines above, DTE Electric submitted the appropriate documentation titled the Notice of Planned Participation (NOPP) to the State of Michigan that formally announced the intent to pursue cessation of coal at the Belle River power plant as their ELG compliance option. No new permits that would require ELG compliance have been issued for other facilities, consequently no compliance timelines have been established. DTE Electric continues to evaluate compliance strategies, technologies and system designs for both FGD wastewater and bottom ash transport water system to achieve compliance with the EPA rules. DTE Electric has estimated the impact of the CCR and ELG rules to be $661 million of capital expenditures, including $516 million for 2021 through 2025. DTE Gas Air — In June 2020, DTE Energy expanded its net zero goal to include its gas utility operations by committing to reduce greenhouse gas emissions to net zero by 2050 from procurement of natural gas through delivery. As part of DTE Energy's 2050 net zero commitment, DTE Gas launched its CleanVision Natural Gas Balance program in January 2021 that offers customers a way to reduce their carbon footprint using carbon offsets and renewable natural gas. The carbon offset program is focused on protecting Michigan forests that naturally absorb carbon dioxide. Contaminated and Other Sites — DTE Gas owns or previously owned 14 former MGP sites. Investigations have revealed contamination related to the by-products of gas manufacturing at each site. Cleanup of eight of the MGP sites is complete, and the sites are closed. DTE Gas has also completed partial closure of four additional sites. Cleanup activities associated with the remaining sites will continue over the next several years. The MPSC has established a cost deferral and rate recovery mechanism for investigation and remediation costs incurred at former MGP sites. In addition to the MGP sites, DTE Gas is also in the process of cleaning up other contaminated sites, including gate stations, gas pipeline releases, and underground storage tank locations. As of September 30, 2021 and December 31, 2020, DTE Gas had $24 million accrued for remediation. These costs are not discounted to their present value. Any change in assumptions, such as remediation techniques, nature and extent of contamination, and regulatory requirements, could impact the estimate of remedial action costs for the sites and affect DTE Gas' financial position and cash flows. DTE Gas anticipates the cost amortization methodology approved by the MPSC, which allows for amortization of the MGP costs over a ten-year period beginning with the year subsequent to the year the MGP costs were incurred, will prevent the associated investigation and remediation costs from having a material adverse impact on DTE Gas' results of operations. Non-utility DTE Energy's non-utility businesses are subject to a number of environmental laws and regulations dealing with the protection of the environment from various pollutants. In March 2019, the EPA issued an FOV to EES Coke, the Michigan coke battery facility that is a wholly-owned subsidiary of DTE Energy, alleging that the 2008 and 2014 permits issued by EGLE did not comply with the Clean Air Act. In September 2020, the EPA issued another FOV alleging EES Coke's 2018 and 2019 SO2 emissions exceeded projections and hence violated non-attainment new source review requirements. EES Coke evaluated the EPA's alleged violations and believes that the permits approved by EGLE complied with the Clean Air Act. EES Coke also responded to the EPA's September 2020 allegations demonstrating its actual emissions are compliant with non-attainment new source review requirements. Discussions with the EPA are ongoing. At the present time, DTE Energy cannot predict the outcome or financial impact of this FOV. Other In 2010, the EPA finalized a new one-hour SO 2 ambient air quality standard that requires states to submit plans and associated timelines for non-attainment areas that demonstrate attainment with the new SO 2 standard in phases. Phase 1 addresses non-attainment areas designated based on ambient monitoring data. Phase 2 addresses non-attainment areas with large sources of SO 2 and modeled concentrations exceeding the National Ambient Air Quality Standards for SO 2 . Phase 3 addresses smaller sources of SO 2 with modeled or monitored exceedances of the new SO 2 standard. Michigan's Phase 1 non-attainment area includes DTE Energy facilities in southwest Detroit and areas of Wayne County. Modeling runs by EGLE suggest that emission reductions may be required by significant sources of SO 2 emissions in these areas, including DTE Electric power plants and DTE Energy's Michigan coke battery facility. As part Michigan's SIP process, DTE Energy has worked with EGLE to develop air permits reflecting significant SO 2 emission reductions that, in combination with other non-DTE Energy sources' emission reduction strategies, will help the state attain the standard and sustain its attainment. The Michigan SIP was completed and submitted to the EPA on May 31, 2016 and supplemented on June 30, 2016. On March 19, 2021, the EPA published in the Federal Register partial approval and partial disapproval of Michigan's Detroit SO2 non-attainment area plan. The partial disapproval does not appear to impact DTE's sources and further discussions are underway with the EPA to finalize the plan. Since several non-DTE Energy sources are also part of the proposed compliance plan, DTE Energy is unable to determine the full impact of any further emissions reductions that may be required from DTE's facilities at this time. Michigan's Phase 2 non-attainment area includes DTE Electric facilities in St. Clair County. EGLE has not made a final determination on SIP strategy for this area, pending the EPA's review of their clean data determination request. Until agency plans are final, DTE Energy is unable to determine the impacts. Synthetic Fuel Guarantees DTE Energy discontinued the operations of its synthetic fuel production facilities throughout the United States as of December 31, 2007. DTE Energy provided certain guarantees and indemnities in conjunction with the sales of interests in its synfuel facilities. The guarantees cover potential commercial, environmental, oil price, and tax-related obligations that will survive until 90 days after expiration of all applicable statutes of limitations. DTE Energy estimates that its maximum potential liability under these guarantees at September 30, 2021 was approximately $400 million. Payment under these guarantees is considered remote. REF Guarantees DTE Energy has provided certain guarantees and indemnities in conjunction with the sales of interests in or lease of its REF facilities. The guarantees cover potential commercial, environmental, and tax-related obligations that will survive until 90 days after expiration of all applicable statutes of limitations. DTE Energy estimates that its maximum potential liability under these guarantees at September 30, 2021 was $698 million. Payments under these guarantees are considered remote. Other Guarantees In certain limited circumstances, the Registrants enter into contractual guarantees. The Registrants may guarantee another entity’s obligation in the event it fails to perform and may provide guarantees in certain indemnification agreements. Finally, the Registrants may provide indirect guarantees for the indebtedness of others. DTE Energy’s guarantees are not individually material with maximum potential payments totaling $40 million at September 30, 2021. Payments under these guarantees are considered remote. The Registrants are 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, 2021, DTE Energy had $171 million of performance bonds outstanding, including $120 million for DTE Electric. In the event that such bonds are called for nonperformance, the Registrants would be obligated to reimburse the issuer of the performance bond. The Registrants are released from the performance bonds as the contractual performance is completed and does not believe that a material amount of any currently outstanding performance bonds will be called. Labor Contracts There are several bargaining units for DTE Energy subsidiaries' approximate 5,100 represented employees, including DTE Electric's approximately 2,700 represented employees. This represents 50% and 57% of DTE Energy's and DTE Electric's total employees, respectively. Of these represented employees, approximately 16% and 21% have contracts expiring within one year for DTE Energy and DTE Electric, respectively. Purchase Commitments Utility capital expenditures, expenditures for non-utility businesses, and contributions to equity method investees will be approximately $3.9 billion and $3.0 billion in 2021 for DTE Energy and DTE Electric, respectively. The Registrants have made certain commitments in connection with the estimated 2021 annual capital expenditures and contributions to equity method investees. COVID-19 Pandemic DTE Energy has been actively monitoring the impact of the COVID-19 pandemic on supply chains, markets, counterparties, and customers, and any related impacts on operating costs, customer demand, and recoverability of assets that could materially impact the Registrants' financial results. In 2021, the COVID-19 pandemic has continued to impact DTE Electric sales volumes. As businesses have maintained certain remote operations, related sales volumes have been lower for commercial and industrial customers and higher for residential customers as compared to historical volumes before the pandemic. This impact contributed to a net reduction in DTE Electric sales, but has been offset by favorable rate mix. In 2020, COVID-19 also resulted in incremental costs at our utilities related to personal protective equipment and other health and safety-related matters, as well as lower volumes for certain companies within the DTE Vantage segment. For the three and nine months ended September 30, 2021, however, there has not been any significant impact to the Registrants' Consolidated Financial Statements. In consideration of the above factors and all other current and expected impacts to the Registrants' performance and cash flows resulting from the COVID-19 pandemic, there have been no material adjustments or reserves deemed necessary as of September 30, 2021. The Registrants cannot predict the future impacts of the COVID-19 pandemic on the Consolidated Financial Statements, as developments involving COVID-19 and its related effects on economic and operating conditions remain highly uncertain. Other Contingencies The Registrants are involved in certain other legal, regulatory, administrative, and environmental proceedings before various courts, arbitration panels, and governmental agencies concerning claims arising in the ordinary course of business. These proceedings include certain contract disputes, additional environmental reviews and investigations, audits, inquiries from various regulators, and pending judicial matters. The Registrants cannot predict the final disposition of such proceedings. The Registrants regularly review legal matters and record provisions for claims that they can estimate and are considered probable of loss. The resolution of these pending proceedings is not expected to have a material effect on the Registrants' Consolidated Financial Statements in the periods they are resolved. For a discussion of contingencies related to regulatory matters and derivatives, see Notes 6 and 9 to the Consolidated Financial Statements, "Regulatory Matters" and "Financial and Other Derivative Instruments," respectively.

Retirement Benefits and Trustee

Retirement Benefits and Trusteed Assets	9 Months Ended
Retirement Benefits and Trusteed Assets	Sep. 30, 2021
Retirement Benefits [Abstract]
Retirement Benefits and Trusteed Assets	RETIREMENT BENEFITS AND TRUSTEED ASSETS The following tables detail the components of net periodic benefit costs (credits) for pension benefits and other postretirement benefits for DTE Energy: Pension Benefits Other Postretirement Benefits Three Months Ended September 30, 2021 2020 2021 2020 (In millions) Service cost $ 27 $ 25 $ 8 $ 7 Interest cost 39 46 12 14 Expected return on plan assets (84) (84) (33) (32) Amortization of: Net actuarial loss 49 43 3 4 Prior service credit — — (5) (5) Settlements — 2 — — Net periodic benefit cost (credit) $ 31 $ 32 $ (15) $ (12) Pension Benefits Other Postretirement Benefits Nine Months Ended September 30, 2021 2020 2021 2020 (In millions) Service cost $ 81 $ 74 $ 23 $ 20 Interest cost 118 139 35 42 Expected return on plan assets (254) (250) (97) (96) Amortization of: Net actuarial loss 147 129 10 12 Prior service credit — — (15) (15) Settlements — 2 — — Net periodic benefit cost (credit) $ 92 $ 94 $ (44) $ (37) DTE Electric participates in various plans that provide pension and other postretirement benefits for DTE Energy and its affiliates. The plans are primarily sponsored by DTE Energy's subsidiary, DTE Energy Corporate Services, LLC. DTE Electric accounts for its participation in DTE Energy's qualified and non-qualified pension plans by applying multiemployer accounting. DTE Electric accounts for its participation in other postretirement benefit plans by applying multiple-employer accounting. Within multiemployer and multiple-employer plans, participants pool plan assets for investment purposes and to reduce the cost of plan administration. The primary difference between plan types is assets contributed in multiemployer plans can be used to provide benefits for all participating employers, while assets contributed within a multiple-employer plan are restricted for use by the contributing employer. As a result of multiemployer accounting treatment, capitalized costs associated with these plans are reflected in Property, plant, and equipment in DTE Electric's Consolidated Statements of Financial Position. The same capitalized costs are reflected as Regulatory assets and liabilities in DTE Energy's Consolidated Statements of Financial Position. In addition, the service cost and non-service cost components are presented in Operation and maintenance in DTE Electric's Consolidated Statements of Operations. The same non-service cost components are presented in Other (Income) and Deductions — Non-operating retirement benefits, net in DTE Energy's Consolidated Statements of Operations. Plan participants of all plans are solely DTE Energy and affiliate participants. DTE Energy's subsidiaries are responsible for their share of qualified and non-qualified pension benefit costs. DTE Electric's allocated portion of pension benefit costs included in capital expenditures and operating and maintenance expense was $26 million and $28 million for the three months ended September 30, 2021 and 2020, respectively, and $78 million and $79 million for the nine months ended September 30, 2021 and 2020, respectively. These amounts include recognized contractual termination benefit charges, curtailment gains, and settlement charges. The following tables detail the components of net periodic benefit costs (credits) for other postretirement benefits for DTE Electric: Three Months Ended September 30, Nine Months Ended September 30, 2021 2020 2021 2020 (In millions) Service cost $ 6 $ 5 $ 17 $ 15 Interest cost 8 11 25 32 Expected return on plan assets (22) (21) (65) (65) Amortization of: Net actuarial loss 3 2 9 8 Prior service credit (3) (3) (10) (10) Net periodic benefit credit $ (8) $ (6) $ (24) $ (20) Pension and Other Postretirement Contributions At the discretion of management and depending upon financial market conditions, DTE Energy anticipates making up to $7 million in contributions to the qualified pension plans in 2021. No amounts relate to DTE Electric and no contributions are anticipated for DTE Energy's postretirement benefit plans in 2021.

Segment and Related Information

Segment and Related Information	9 Months Ended
Segment and Related Information	Sep. 30, 2021
Segment Reporting [Abstract]
Segment and Related Information	SEGMENT AND RELATED INFORMATION DTE Energy sets strategic goals, allocates resources, and evaluates performance based on the following structure: Electric segment consists principally of DTE Electric, which is engaged in the generation, purchase, distribution, and sale of electricity to approximately 2.3 million residential, commercial, and industrial customers in southeastern Michigan. Gas segment consists principally of DTE Gas, which is engaged in the purchase, storage, transportation, distribution, and sale of natural gas to approximately 1.3 million residential, commercial, and industrial customers throughout Michigan and the sale of storage and transportation capacity. DTE Vantage , formerly the Power and Industrial Projects segment, is comprised primarily of projects that deliver energy and utility-type products and services to industrial, commercial, and institutional customers, produce reduced emissions fuel, and sell electricity and pipeline-quality gas from renewable energy projects. Energy Trading consists of energy marketing and trading operations. Corporate and Other includes various holding company activities, holds certain non-utility debt, and holds certain investments, including funds supporting regional development and economic growth. DTE Energy completed the separation of DT Midstream on July 1, 2021, which was comprised of the Gas Storage and Pipelines segment and also certain DTE Energy holding company activity within the Corporate and Other segment. Amounts relating to DT Midstream have been classified as discontinued operations, and Gas Storage and Pipelines is no longer a reportable segment of DTE Energy. Refer to Note 4 to the Consolidated Financial Statements, “Dispositions and Impairments,” for additional information. The federal income tax provisions or benefits of DTE Energy’s subsidiaries are determined on an individual company basis and recognize the tax benefit of tax credits and net operating losses, if applicable. The state and local income tax provisions of the utility subsidiaries are also determined on an individual company basis and recognize the tax benefit of various tax credits and net operating losses, if applicable. The subsidiaries record federal, state, and local income taxes payable to or receivable from DTE Energy based on the federal, state, and local tax provisions of each company. Inter-segment billing for goods and services exchanged between segments is based upon tariffed or market-based prices of the provider and primarily consists of the sale of reduced emissions fuel, power sales, natural gas sales, and renewable natural gas sales in the following segments: Three Months Ended September 30, Nine Months Ended September 30, 2021 2020 2021 2020 (In millions) Electric $ 17 $ 16 $ 48 $ 46 Gas 3 4 10 12 DTE Vantage 125 134 463 308 Energy Trading 9 9 35 23 Corporate and Other 1 1 2 2 $ 155 $ 164 $ 558 $ 391 Financial data of DTE Energy's business segments follows: Three Months Ended September 30, Nine Months Ended September 30, 2021 2020 2021 2020 (In millions) Operating Revenues — Utility operations Electric $ 1,700 $ 1,690 $ 4,468 $ 4,211 Gas 193 173 1,070 964 Operating Revenues — Non-utility operations Electric 2 3 9 10 DTE Vantage 372 324 1,132 850 Energy Trading 1,602 1,061 4,208 2,714 Corporate and Other 1 1 2 2 Reconciliation and Eliminations (a) (155) (172) (572) (408) Total $ 3,715 $ 3,080 $ 10,317 $ 8,343 _______________________________________ (a) Includes $14 million for the nine months ended September 30, 2021 and $8 million and $17 million for the three and nine months ended September 30, 2020, respectively, for eliminations related to DTE Energy's prior Gas Storage and Pipelines segment that remain in continuing operations. Eliminations for these revenues are offset by related cost eliminations and have no impact on DTE Energy net income. Three Months Ended September 30, Nine Months Ended September 30, 2021 2020 2021 2020 (In millions) Net Income (Loss) Attributable to DTE Energy by Segment: Electric $ 342 $ 398 $ 788 $ 675 Gas (30) (20) 146 102 DTE Vantage 73 47 115 102 Energy Trading (52) (28) (173) 5 Corporate and Other (275) (25) (381) (40) Discontinued Operations (33) 104 106 249 Net Income Attributable to DTE Energy Company $ 25 $ 476 $ 601 $ 1,093

Significant Accounting Polici_2

Significant Accounting Policies (Policies)	9 Months Ended
Significant Accounting Policies (Policies)	Sep. 30, 2021
Accounting Policies [Abstract]
Basis of Presentation	Basis of Presentation The Consolidated Financial Statements should be read in conjunction with the Combined Notes to Consolidated Financial Statements included in the combined DTE Energy and DTE Electric 2020 Annual Report on Form 10-K. The accompanying Consolidated Financial Statements of the Registrants are prepared using accounting principles generally accepted in the United States of America. These accounting principles require management to use estimates and assumptions that impact reported amounts of assets, liabilities, revenues and expenses, and the disclosure of contingent assets and liabilities. Actual results may differ from the Registrants' estimates. The Consolidated Financial Statements are unaudited but, in the Registrants' opinions, include all adjustments necessary to present a fair statement of the results for the interim periods. All adjustments are of a normal recurring nature, except as otherwise disclosed in these Consolidated Financial Statements and Combined Notes to Consolidated Financial Statements. Financial results for this interim period are not necessarily indicative of results that may be expected for any other interim period or for the fiscal year ending December 31, 2021. 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 DTE Electric were reclassified to match the current year's Consolidated Financial Statements presentation. Separation of DT Midstream On July 1, 2021, DTE Energy completed the previously announced separation of its natural gas pipeline, storage and gathering non-utility business. Effective with the separation, DTE retains no ownership in the new company, DT Midstream, which was formerly comprised of DTE Energy's Gas Storage and Pipelines segment and also included certain DTE Energy holding company activity within the Corporate and Other segment. Gas Storage and Pipelines is no longer a reportable segment of DTE Energy, and financial results of DT Midstream are presented as Income from discontinued operations, net of taxes on DTE Energy's Consolidated Statements of Operations. Assets and liabilities of DT Midstream are also presented as discontinued operations on DTE Energy's Consolidated Statements of Financial Position. Prior periods have been recast to reflect this presentation.
Principles of Consolidation	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 equity investment is valued at cost minus any impairments, if applicable. 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. During the third quarter of 2021, the Registrants performed reassessments of certain VIEs owned by DT Midstream. Upon the separation of DT Midstream, DTE Energy no longer owns any interest in SGG, owner and operator of certain midstream natural gas assets. Therefore, SGG has been removed from the amounts for DTE Energy's consolidated VIEs in the table below. Additionally, as a result of the separation of DT Midstream, DTE Energy no longer has an equity interest in NEXUS, owner of a 256-mile pipeline which transports shale gas to Ohio, Michigan, and Ontario market centers. DTE Energy has removed its equity investment in NEXUS from the amounts for its non-consolidated VIEs. The Registrants maintain a variable interest in NEXUS relating to DTE Electric's transportation services contract. Assets, liabilities, and earnings related to SGG and NEXUS are included in discontinued operations in the Consolidated Financial Statements. Legal entities within the DTE Vantage 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. The Registrants hold ownership interests in certain limited partnerships. The limited partnerships include investment funds which support regional development and economic growth, and 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 September 30, 2021, 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 September 30, 2021, 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 13 to the Consolidated Financial Statements, "Commitments and Contingencies," related to 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.
Changes in Accumulated Other Comprehensive Income (Loss)	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, 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.
Cash, Cash Equivalents, and Restricted Cash	Cash, Cash Equivalents, and Restricted Cash Cash and cash equivalents include cash on hand, cash in banks, and temporary investments purchased with remaining maturities of three months or less. Restricted cash consists of funds held in separate bank accounts to satisfy contractual obligations and guarantee performance. Restricted cash designated for payments within one year is classified as a Current Asset.
Financing Receivables	Financing Receivables Financing receivables are primarily composed of trade receivables, notes receivable, and unbilled revenue. The Registrants' financing receivables are stated at net realizable value. The Registrants monitor the credit quality of their financing receivables on a regular basis by reviewing credit quality indicators and monitoring for trigger events, such as a credit rating downgrade or bankruptcy. Credit quality indicators include, but are not limited to, ratings by credit agencies where available, collection history, collateral, counterparty financial statements and other internal metrics. Utilizing such data, the Registrants have determined three internal grades of credit quality. Internal grade 1 includes financing receivables for counterparties where credit rating agencies have ranked the counterparty as investment grade. To the extent credit ratings are not available, the Registrants utilize other credit quality indicators to determine the level of risk associated with the financing receivable. Internal grade 1 may include financing receivables for counterparties for which credit rating agencies have ranked the counterparty as below investment grade; however, due to favorable information on other credit quality indicators, the Registrants have determined the risk level to be similar to that of an investment grade counterparty. Internal grade 2 includes financing receivables for counterparties with limited credit information and those with a higher risk profile based upon credit quality indicators. Internal grade 3 reflects financing receivables for which the counterparties have the greatest level of risk, including those in bankruptcy status. The following represents the Registrants' financing receivables by year of origination, classified by internal grade of credit risk. The related credit quality indicators and risk ratings utilized to develop the internal grades have been updated through September 30, 2021. DTE Energy DTE Electric Year of Origination 2021 2020 2019 and Prior Total 2021 and Prior (In millions) Notes receivable Internal grade 1 $ — $ — $ 19 $ 19 $ 14 Internal grade 2 2 100 21 123 3 Internal grade 3 — — — — — Total notes receivable (a) $ 2 $ 100 $ 40 $ 142 $ 17 Net investment in leases Net investment in leases, internal grade 1 $ — $ 2 $ 39 $ 41 $ — Net investment in leases, internal grade 2 — 159 1 160 — Total net investment in leases (a) $ — $ 161 $ 40 $ 201 $ — _______________________________________ (a) For DTE Energy, included in Current Assets — Other and Other Assets — Notes Receivable on the Consolidated Statements of Financial Position. For DTE Electric, included in Current Assets — Other on the Consolidated Statements of Financial Position. The allowance for doubtful accounts on accounts receivable for the utility entities is generally calculated using an 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 and future 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 generally 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 non-utility businesses and other receivables for both utility and non-utility businesses is generally calculated based on specific review of probable future collections based on receivable balances generally in excess of 30 days. Existing and future economic conditions, customer trends and other factors are also considered. Receivables are written off on a specific identification basis and determined based upon the specific circumstances of the associated receivable. Notes receivable for DTE Energy are primarily comprised of finance lease receivables and loans that are included in Notes Receivable and Other current assets on DTE Energy's Consolidated Statements of Financial Position. Notes receivable 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. 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 including existing and future economic conditions. Cash payments received on nonaccrual status notes receivable, that do not bring the account contractually current, are first applied to the contractually owed past due interest, with any remainder applied to principal. Accrual of interest is generally resumed when the note receivable becomes contractually current.
Recently Adopted and Recently Issued Pronouncements	Recently Adopted Pronouncements In December 2019, the FASB issued ASU No. 2019-12, Income Taxes (Topic 740) - Simplifying the Accounting for Income Taxes . The amendments in this update simplify the accounting for income taxes by removing certain exceptions, and clarifying certain requirements regarding franchise taxes, goodwill, consolidated tax expenses, and annual effective tax rate calculations. The Registrants adopted the ASU effective January 1, 2021 using the modified retrospective and prospective approaches, where applicable. The adoption of the ASU did not have a significant impact on the Registrants' Consolidated Financial Statements. In August 2020, the FASB issued ASU No. 2020-06, Debt - Debt with Conversion and Other Options (Subtopic 470-20) and Derivatives and Hedging - Contracts in Entity's Own Equity (Subtopic 815-40): Accounting for Convertible Instruments and Contracts in an Entity's Own Equity. The amendments in this update simplify the accounting for certain financial instruments with characteristics of liabilities and equity, including convertible instruments and contracts indexed to and potentially settled in an entity's own equity. The Registrants adopted the ASU effective January 1, 2021 using the modified retrospective approach. The adoption of the ASU did not have a significant impact on the Registrants' Consolidated Financial Statements. Recently Issued Pronouncements In March 2020, the FASB issued ASU No. 2020-04, Reference Rate Reform (Topic 848) - Facilitation of the Effects of Reference Rate Reform on Financial Reporting, as amended . The amendments in this update provide optional expedients and exceptions for applying GAAP to contract modifications and hedging relationships, subject to meeting certain criteria, that reference LIBOR or another reference rate expected to be discontinued. The guidance can be applied prospectively from any date beginning March 12, 2020 through December 31, 2022. The optional relief is temporary and cannot be applied to contract modifications and hedging relationships entered into or evaluated after December 31, 2022. The Registrants presently have various contracts that reference LIBOR and are assessing how this standard may be applied to specific contract modifications. In July 2021, the FASB issued ASU No. 2021-05, Leases (Topic 842): Lessors – Certain Leases with Variable Lease Payments.
Fair Value Measurement	Fair value is defined as the price that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date in a principal or most advantageous market. Fair value is a market-based measurement that is determined based on inputs, which refer broadly to assumptions that market participants use in pricing assets or liabilities. These inputs can be readily observable, market corroborated, or generally unobservable inputs. The Registrants make certain assumptions they believe that market participants would use in pricing assets or liabilities, including assumptions about risk, and the risks inherent in the inputs to valuation techniques. Credit risk of the Registrants and their counterparties is incorporated in the valuation of assets and liabilities through the use of credit reserves, the impact of which was immaterial at September 30, 2021 and December 31, 2020. The Registrants believe they use valuation techniques that maximize the use of observable market-based inputs and minimize the use of unobservable inputs. A fair value hierarchy has been established that prioritizes the inputs to valuation techniques used to measure fair value in three broad levels. The fair value hierarchy gives the highest priority to quoted prices (unadjusted) in active markets for identical assets or liabilities (Level 1) and the lowest priority to unobservable inputs (Level 3). In some cases, the inputs used to measure fair value might fall in different levels of the fair value hierarchy. All assets and liabilities are required to be classified in their entirety based on the lowest level of input that is significant to the fair value measurement in its entirety. Assessing the significance of a particular input may require judgment considering factors specific to the asset or liability and may affect the valuation of the asset or liability and its placement within the fair value hierarchy. The Registrants classify fair value balances based on the fair value hierarchy defined as follows: • Level 1 — Consists of unadjusted quoted prices in active markets for identical assets or liabilities that the Registrants have the ability to access as of the reporting date. • Level 2 — Consists of inputs other than quoted prices included within Level 1 that are directly observable for the asset or liability or indirectly observable through corroboration with observable market data. • Level 3 — Consists of unobservable inputs for assets or liabilities whose fair value is estimated based on internally developed models or methodologies using inputs that are generally less readily observable and supported by little, if any, market activity at the measurement date. Unobservable inputs are developed based on the best available information and subject to cost-benefit constraints.
Nuclear Decommissioning Trusts and Other Investments	Nuclear Decommissioning Trusts and Other Investments The nuclear decommissioning trusts and other investments hold debt and equity securities directly and indirectly through commingled funds. Exchange-traded debt and equity securities held directly, as well as publicly-traded commingled funds, are valued using quoted market prices in actively traded markets. Non-exchange traded fixed income securities are valued based upon quotations available from brokers or pricing services. Non-publicly traded commingled funds holding exchange-traded equity or debt securities are valued based on stated NAVs. There are no significant restrictions for these funds and investments may be redeemed with 7 to 65 days notice depending on the fund. There is no intention to sell the investment in these commingled funds. Private equity and other assets include a diversified group of funds that are classified as NAV assets. These funds primarily invest in limited partnerships, including private equity, private real estate and private credit. Distributions are received through the liquidation of the underlying fund assets over the life of the funds. There are generally no redemption rights. The limited partner must hold the fund for its life or find a third-party buyer, which may need to be approved by the general partner. The funds are established with varied contractual durations generally in the range of 7 years to 12 years. The fund life can often be extended by several years by the general partner, and further extended with the approval of the limited partners. Unfunded commitments related to these investments totaled $155 million and $183 million as of September 30, 2021 and December 31, 2020, respectively. For pricing the nuclear decommissioning trusts and other investments, 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 source of a given security if the trustee determines that another price source is considered preferable. The Registrants have obtained an understanding of how these prices are derived, including the nature and observability of the inputs used in deriving such prices.
Derivative Assets and Liabilities	Derivative Assets and Liabilities Derivative assets and liabilities are comprised of physical and financial derivative contracts, including futures, forwards, options, and swaps that are both exchange-traded and over-the-counter traded contracts. Various inputs are used to value derivatives depending on the type of contract and availability of market data. Exchange-traded derivative contracts are valued using quoted prices in active markets. The Registrants consider the following criteria in determining whether a market is considered active: frequency in which pricing information is updated, variability in pricing between sources or over time, and the availability of public information. Other derivative contracts are valued based upon a variety of inputs including commodity market prices, broker quotes, interest rates, credit ratings, default rates, market-based seasonality, and basis differential factors. The Registrants monitor the prices that are supplied by brokers and pricing services and may use a supplemental price source or change the primary price source of an index if prices become unavailable or another price source is determined to be more representative of fair value. The Registrants have obtained an understanding of how these prices are derived. Additionally, the Registrants selectively corroborate the fair value of their transactions by comparison of market-based price sources. Mathematical valuation models are used for derivatives for which external market data is not readily observable, such as contracts which extend beyond the actively traded reporting period. The Registrants have established a Risk Management Committee whose responsibilities include directly or indirectly ensuring all valuation methods are applied in accordance with predefined policies. The development and maintenance of the Registrants' forward price curves has been assigned to DTE Energy's Risk Management Department, which is separate and distinct from the trading functions within DTE Energy.
Fair Value Transfer	Derivatives are transferred between levels primarily due to changes in the source data used to construct price curves as a result of changes in market liquidity. Transfers in and transfers out are reflected as if they had occurred at the beginning of the period.
Derivatives	The Registrants recognize all derivatives at their fair value as Derivative assets or liabilities on their respective Consolidated Statements of Financial Position unless they qualify for certain scope exceptions, including the normal purchases and normal sales exception. Further, derivatives that qualify and are designated for hedge accounting are classified as either hedges of a forecasted transaction or the variability of cash flows to be received or paid related to a recognized asset or liability (cash flow hedge); or as hedges of the fair value of a recognized asset or liability or of an unrecognized firm commitment (fair value hedge). For cash flow hedges, the derivative gain or loss is deferred in Accumulated other comprehensive income (loss) and later reclassified into earnings when the underlying transaction occurs. For fair value hedges, changes in fair values for the derivative and hedged item are recognized in earnings each period. For derivatives that do not qualify or are not designated for hedge accounting, changes in fair value are recognized in earnings each period. The Registrants' primary market risk exposure is associated with commodity prices, credit, and interest rates. The Registrants have risk management policies to monitor and manage market risks. The Registrants use derivative instruments to manage some of the exposure. DTE Energy uses derivative instruments for trading purposes in its Energy Trading segment. Contracts classified as derivative instruments include electricity, natural gas, oil, certain environmental contracts, forwards, futures, options, swaps, and foreign currency exchange contracts. Items not classified as derivatives include natural gas and environmental inventory, pipeline transportation contracts, certain environmental contracts, and natural gas storage assets. DTE Electric — DTE Electric generates, purchases, distributes, and sells electricity. DTE Electric uses forward contracts to manage changes in the price of electricity and fuel. Substantially all of these contracts meet the normal purchases and normal sales exception and are therefore accounted for under the accrual method. Other derivative contracts are MTM and recoverable through the PSCR mechanism when settled. This results in the deferral of unrealized gains and losses as Regulatory assets or liabilities until realized. DTE Gas — DTE Gas purchases, stores, transports, distributes, and sells natural gas, and buys and sells transportation and storage capacity. DTE Gas has fixed-priced contracts for portions of its expected natural gas supply requirements through March 2024. Substantially all of these contracts meet the normal purchases and normal sales exception and are therefore accounted for under the accrual method. Forward transportation and storage contracts are generally not derivatives and are therefore accounted for under the accrual method. DTE Vantage — This segment manages and operates industrial energy projects, reduced emissions fuel projects, renewable gas recovery, and power generation assets. Primarily fixed-price contracts are used in the marketing and management of the segment assets. These contracts are generally not derivatives and are therefore accounted for under the accrual method. Energy Trading — Commodity Price Risk — Energy Trading markets and trades electricity, natural gas physical products, and energy financial instruments, and provides energy and asset management services utilizing energy commodity derivative instruments. Forwards, futures, options, and swap agreements are used to manage exposure to the risk of market price and volume fluctuations in its operations. These derivatives are accounted for by recording changes in fair value to earnings unless hedge accounting criteria are met. Energy Trading — Foreign Currency Exchange Risk — Energy Trading has foreign currency exchange forward contracts to economically hedge fixed Canadian dollar commitments existing under natural gas and power purchase and sale contracts and natural gas transportation contracts. Energy Trading enters into these contracts to mitigate price volatility with respect to fluctuations of the Canadian dollar relative to the U.S. dollar. These derivatives are accounted for by recording changes in fair value to earnings unless hedge accounting criteria are met. Corporate and Other — Interest Rate Risk — DTE Energy may use interest rate swaps, treasury locks, and other derivatives to hedge the risk associated with interest rate market volatility. Credit Risk — DTE Energy maintains credit policies that significantly minimize overall credit risk. These policies include an evaluation of potential customers’ and counterparties’ financial condition, including the viability of underlying productive assets, credit rating, collateral requirements, or other credit enhancements such as letters of credit or guarantees. DTE Energy generally uses standardized agreements that allow the netting of positive and negative transactions associated with a single counterparty. DTE Energy maintains a provision for credit losses based on factors surrounding the credit risk of its customers, historical trends, and other information. Based on DTE Energy's credit policies and its September 30, 2021 provision for credit losses, DTE Energy’s exposure to counterparty nonperformance is not expected to have a material adverse effect on DTE Energy's Consolidated Financial Statements.
Derivatives, Offsetting Fair Value Amounts	Certain of DTE Energy's derivative positions are subject to netting arrangements which provide for offsetting of asset and liability positions as well as related cash collateral. Such netting arrangements generally do not have restrictions. Under such netting arrangements, DTE Energy offsets the fair value of derivative instruments with cash collateral received or paid for those contracts executed with the same counterparty, which reduces DTE Energy's Total Assets and Liabilities. Cash collateral is allocated between the fair value of derivative instruments and customer accounts receivable and payable with the same counterparty on a pro-rata basis to the extent there is exposure. Any cash collateral remaining, after the exposure is netted to zero, is reflected in Accounts receivable and Accounts payable as collateral paid or received, respectively. DTE Energy also provides and receives collateral in the form of letters of credit which can be offset against net Derivative assets and liabilities as well as Accounts receivable and payable. DTE Energy had issued letters of credit of $20 million and $7 million outstanding at September 30, 2021 and December 31, 2020, respectively, which could be used to offset net Derivative liabilities. Letters of credit received from third parties which could be used to offset net Derivative assets were $55 million and $9 million at September 30, 2021 and December 31, 2020, respectively. Such balances of letters of credit are excluded from the tables below and are not netted with the recognized assets and liabilities in DTE Energy's Consolidated Statements of Financial Position. For contracts with certain clearing agents, the fair value of derivative instruments is netted against realized positions with the net balance reflected as either 1) a Derivative asset or liability or 2) an Account receivable or payable. Other than certain clearing agents, Accounts receivable and Accounts payable that are subject to netting arrangements have not been offset against the fair value of Derivative assets and liabilities.
Derivatives, Methods of Accounting	Revenues and energy costs related to trading contracts are presented on a net basis in DTE Energy's Consolidated Statements of Operations. Commodity derivatives used for trading purposes, and financial non-trading commodity derivatives, are accounted for using the MTM method with unrealized and realized gains and losses recorded in Operating Revenues — Non-utility operations. Non-trading physical commodity sale and purchase derivative contracts are generally accounted for using the MTM method with unrealized and realized gains and losses for sales recorded in Operating Revenues — Non-utility operations and purchases recorded in Fuel, purchased power, gas, and other — non-utility.
Income Tax	The federal income tax provisions or benefits of DTE Energy’s subsidiaries are determined on an individual company basis and recognize the tax benefit of tax credits and net operating losses, if applicable. The state and local income tax provisions of the utility subsidiaries are also determined on an individual company basis and recognize the tax benefit of various tax credits and net operating losses, if applicable. The subsidiaries record federal, state, and local income taxes payable to or receivable from DTE Energy based on the federal, state, and local tax provisions of each company.

Organization and Basis of Pre_2

Organization and Basis of Presentation (Tables)	9 Months Ended
Organization and Basis of Presentation (Tables)	Sep. 30, 2021
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Schedule of Variable Interest Entities	The following table summarizes the major Consolidated Statements of Financial Position items for consolidated VIEs as of September 30, 2021 and December 31, 2020. 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: September 30, 2021 December 31, 2020 (In millions) ASSETS Cash and cash equivalents $ 23 $ 20 Accounts receivable 26 28 Inventories 45 107 Property, plant, and equipment, net 5 14 Notes receivable and other 67 33 $ 166 $ 202 LIABILITIES Accounts payable $ 21 $ 22 Short-term borrowings 74 38 Other current and long-term liabilities 2 4 $ 97 $ 64
Summary of Amounts for Non-Consolidated Variable Interest Entities	Amounts for DTE Energy's non-consolidated VIEs are as follows: September 30, 2021 December 31, 2020 (In millions) Investments in equity method investees $ 170 $ 159 Notes receivable $ 16 $ 21 Future funding commitments $ 3 $ 6

Significant Accounting Polici_3

Significant Accounting Policies (Tables)	9 Months Ended
Significant Accounting Policies (Tables)	Sep. 30, 2021
Accounting Policies [Abstract]
Schedule of Other Income	The following is a summary of DTE Energy's Other income: Three Months Ended September 30, Nine Months Ended September 30, 2021 2020 2021 2020 (In millions) Income from REF entities $ 57 $ 43 $ 102 $ 95 Equity earnings of equity method investees 17 12 31 21 Contract services 6 7 21 20 Allowance for equity funds used during construction 7 6 20 19 Gains from rabbi trust securities (a) — 2 4 24 Other 3 5 9 9 $ 90 $ 75 $ 187 $ 188 _______________________________________ (a) Losses from rabbi trust securities are recorded separately to Other expenses on the Consolidated Statements of Operations. The following is a summary of DTE Electric's Other income: Three Months Ended September 30, Nine Months Ended September 30, 2021 2020 2021 2020 (In millions) Contract services $ 6 $ 7 $ 21 $ 20 Allowance for equity funds used during construction 6 6 18 18 Gains from rabbi trust securities allocated from DTE Energy (a) — 2 4 24 Other 2 3 9 6 $ 14 $ 18 $ 52 $ 68 _______________________________________ (a) Losses from rabbi trust securities are recorded separately to Other expenses on the Consolidated Statements of Operations.
Schedule of Effective Tax Rates	The interim effective tax rates of the Registrants are as follows: Effective Tax Rate Three Months Ended September 30, Nine Months Ended September 30, 2021 2020 2021 2020 DTE Energy 186 % 5 % (34) % 2 % DTE Electric 12 % 13 % 10 % 12 %
Schedule of Financing Receivables Classified by Internal Grade of Credit Risk	The following represents the Registrants' financing receivables by year of origination, classified by internal grade of credit risk. The related credit quality indicators and risk ratings utilized to develop the internal grades have been updated through September 30, 2021. DTE Energy DTE Electric Year of Origination 2021 2020 2019 and Prior Total 2021 and Prior (In millions) Notes receivable Internal grade 1 $ — $ — $ 19 $ 19 $ 14 Internal grade 2 2 100 21 123 3 Internal grade 3 — — — — — Total notes receivable (a) $ 2 $ 100 $ 40 $ 142 $ 17 Net investment in leases Net investment in leases, internal grade 1 $ — $ 2 $ 39 $ 41 $ — Net investment in leases, internal grade 2 — 159 1 160 — Total net investment in leases (a) $ — $ 161 $ 40 $ 201 $ — _______________________________________ (a) For DTE Energy, included in Current Assets — Other and Other Assets — Notes Receivable on the Consolidated Statements of Financial Position. For DTE Electric, included in Current Assets — Other on the Consolidated Statements of Financial Position.
Schedule of Roll-Forward of Activity for Financing Receivables Credit Loss Reserves	The following tables present a roll-forward of the activity for the Registrants' financing receivables credit loss reserves: DTE Energy DTE Electric Trade accounts receivable Other receivables Total Trade and other accounts receivable (In millions) Beginning reserve balance, January 1, 2021 $ 101 $ 3 $ 104 $ 57 Current period provision 41 1 42 27 Write-offs charged against allowance (92) (1) (93) (58) Recoveries of amounts previously written off 49 — 49 29 Ending reserve balance, September 30, 2021 $ 99 $ 3 $ 102 $ 55 DTE Energy DTE Electric Trade accounts receivable Other receivables Total Trade and other accounts receivable (In millions) Beginning reserve balance, January 1, 2020 (a) $ 79 $ 4 $ 83 $ 46 Current period provision 102 3 105 61 Write-offs charged against allowance (130) (4) (134) (80) Recoveries of amounts previously written off 50 — 50 30 Ending reserve balance, December 31, 2020 $ 101 $ 3 $ 104 $ 57 _______________________________________
Schedule of Uncollectible Expense	Uncollectible expense for the Registrants is primarily comprised of the current period provision for allowance for doubtful accounts and is summarized as follows: Three Months Ended September 30, Nine Months Ended September 30, 2021 2020 2021 2020 (In millions) DTE Energy $ 7 $ 22 $ 42 $ 72 DTE Electric 10 16 26 42

Dispositions and Impairments (T

Dispositions and Impairments (Tables)	9 Months Ended
Dispositions and Impairments (Tables)	Sep. 30, 2021
Discontinued Operations and Disposal Groups [Abstract]
Disposal Groups, Including Discontinued Operations	The table below reflects the financial results of DT Midstream that have been reclassified from continuing operations and included in discontinued operations within the Consolidated Statements of Operations. These results include the impact of tax-related adjustments and all transaction costs related to the separation. General corporate overhead costs have been excluded and no portion of corporate interest costs were allocated to discontinued operations. Three Months Ended September 30, Nine Months Ended September 30, 2021 2020 2021 2020 (In millions) Operating Revenues — Non-utility operations $ — $ 204 $ 405 $ 546 Operating Expenses Cost of gas and other — non-utility — 6 15 14 Operation and maintenance (a) 30 32 124 80 Depreciation and amortization — 38 82 110 Taxes other than income — 3 13 12 Asset (gains) losses and impairments, net — (4) 17 (4) 30 75 251 212 Operating Income (Loss) (30) 129 154 334 Other (Income) and Deductions Interest expense — 29 50 82 Interest income — (4) (4) (6) Other income — (45) (62) (98) — (20) (16) (22) Income (Loss) from Discontinued Operations Before Income Taxes (30) 149 170 356 Income Tax Expense 3 42 58 99 Income (Loss) from Discontinued Operations, Net of Taxes (33) 107 112 257 Less: Net Income Attributable to Noncontrolling Interests — 3 6 8 Net Income (Loss) from Discontinued Operations $ (33) $ 104 $ 106 $ 249 _______________________________________ (a) Includes separation transaction costs of $30 million and $59 million for the three and nine months ended September 30, 2021, respectively, for various legal, accounting and other professional services fees. There were no costs incurred in the comparable prior year periods. Total transaction costs of $67 million have been incurred since October 2020. The table below reflects the major assets and liabilities that were transferred to DT Midstream and presented as discontinued operations in the Consolidated Statements of Financial Position as of December 31, 2020. December 31, 2020 (In millions) Total Assets of Discontinued Operations Cash $ 42 Accounts receivable 126 Inventories 8 Other 44 Current assets of DT Midstream 220 Less: Previously affiliated amounts eliminated at DTE Energy 3 Current assets of discontinued operations for DTE Energy 217 Investments in equity method investees 1,691 Net property, plant, and equipment 3,470 Goodwill 473 Intangible assets 2,140 Notes receivable 19 Operating lease right-of-use assets 45 Other 21 Noncurrent assets of discontinued operations for DTE Energy 7,859 Total Assets of Discontinued Operations for DTE Energy $ 8,076 Total Liabilities of Discontinued Operations Accounts payable $ 39 Operating lease liabilities 17 Short-term borrowings due to DTE Energy (a) 2,913 Other 53 Current liabilities of DT Midstream 3,022 Less: Previously affiliated amounts eliminated at DTE Energy 2,923 Current liabilities of discontinued operations for DTE Energy 99 Deferred income taxes 753 Asset retirement obligations 10 Operating lease liabilities 28 Other 45 Noncurrent liabilities of discontinued operations for DTE Energy 836 Total Liabilities of Discontinued Operations for DTE Energy $ 935 ______________________________________ (a) Short-term borrowings due to DTE Energy resulted in an intercompany note receivable in the Corporate and Other segment at December 31, 2020. The settlement of these borrowings in June 2021 and use of proceeds to redeem DTE Energy long-term debt in the third quarter 2021 has reduced the Total Assets of the Corporate and Other segment in the current period. Other changes in DTE Energy's Total Assets due to the separation of DT Midstream primarily relate to the elimination of Gas Storage and Pipelines segment assets in 2021. The following table is a summary of significant non-cash items, capital expenditures, and significant financing activities of discontinued operations included in DTE Energy's Consolidated Statements of Cash Flows: Nine Months Ended September 30, 2021 2020 (In millions) Operating Activities Depreciation and amortization $ 82 $ 110 Deferred income taxes 57 95 Equity earnings of equity method investees (59) (75) Asset (gains) losses and impairments, net 19 (4) Investing Activities Plant and equipment expenditures — non-utility $ (60) $ (440) Financing Activities Acquisition related deferred payment, excluding accretion $ — $ (380)

Revenue (Tables)

Revenue (Tables)	9 Months Ended
Revenue (Tables)	Sep. 30, 2021
Revenue from Contract with Customer [Abstract]
Disaggregation of Revenue	The following is a summary of revenues disaggregated by segment for DTE Energy: Three Months Ended September 30, Nine Months Ended September 30, 2021 2020 2021 2020 (In millions) Electric (a) Residential $ 885 $ 900 $ 2,262 $ 2,169 Commercial 533 498 1,452 1,313 Industrial 167 157 473 434 Other (b) 117 138 290 305 Total Electric operating revenues $ 1,702 $ 1,693 $ 4,477 $ 4,221 Gas Gas sales $ 95 $ 92 $ 726 $ 655 End User Transportation 38 34 171 154 Intermediate Transportation 16 15 59 57 Other (b) 44 32 114 98 Total Gas operating revenues $ 193 $ 173 $ 1,070 $ 964 Other segment operating revenues DTE Vantage $ 372 $ 324 $ 1,132 $ 850 Energy Trading $ 1,602 $ 1,061 $ 4,208 $ 2,714 _______________________________________ (a) Revenues generally represent those of DTE Electric, except $2 million and $3 million of Other revenues related to DTE Sustainable Generation for the three months ended September 30, 2021 and 2020, respectively, and $9 million and $10 million for the nine months ended September 30, 2021 and 2020, respectively. (b) Includes revenue adjustments related to various regulatory mechanisms. Revenues included the following which were outside the scope of Topic 606: Three Months Ended September 30, Nine Months Ended September 30, 2021 2020 2021 2020 (In millions) Electric — Other revenues $ 6 $ 8 $ 14 $ 18 Gas — Alternative Revenue Programs — — — 2 Gas — Other revenues 1 2 5 7 DTE Vantage — Leases 26 26 70 74 Energy Trading — Derivatives 1,324 731 3,377 1,835
Summary of Deferred Revenue Activity	The following is a summary of deferred revenue activity: DTE Energy (In millions) Beginning Balance, January 1, 2021 (a) $ 65 Increases due to cash received or receivable, excluding amounts recognized as revenue during the period 79 Revenue recognized that was included in the deferred revenue balance at the beginning of the period (19) Ending Balance, September 30, 2021 $ 125 _______________________________________
Deferred Revenue Amounts Expected to be Recognized as Revenue in Future Periods	The following table represents deferred revenue amounts for DTE Energy that are expected to be recognized as revenue in future periods: DTE Energy (In millions) 2021 $ 72 2022 50 2023 1 2024 1 2025 — 2026 and thereafter 1 $ 125 The Registrants expect to recognize revenue for the following amounts related to fixed consideration associated with remaining performance obligations in each of the future periods noted: DTE Energy DTE Electric (In millions) 2021 $ 41 $ 2 2022 308 8 2023 264 7 2024 159 7 2025 80 1 2026 and thereafter 421 — $ 1,273 $ 25

Common Stock and Earnings Per_2

Common Stock and Earnings Per Share (Tables)	9 Months Ended
Common Stock and Earnings Per Share (Tables)	Sep. 30, 2021
Earnings Per Share [Abstract]
Schedule of Earnings Per Share, Basic and Diluted	The following is a reconciliation of DTE Energy's basic and diluted income per share calculation: Three Months Ended September 30, Nine Months Ended September 30, 2021 2020 2021 2020 (In millions, except per share amounts) Basic Earnings per Share Net Income attributable to DTE Energy — continuing operations $ 58 $ 372 $ 495 $ 844 Less: Allocation of earnings to net restricted stock awards — 1 1 2 $ 58 $ 371 $ 494 $ 842 Net Income (Loss) attributable to DTE Energy — discontinued operations (33) 104 106 249 Net income available to common shareholders — basic $ 25 $ 475 $ 600 $ 1,091 Average number of common shares outstanding — basic 193 193 193 192 Income from continuing operations $ 0.30 $ 1.93 $ 2.55 $ 4.37 Income (loss) from discontinued operations (0.17) 0.54 0.55 1.30 Basic Earnings per Common Share $ 0.13 $ 2.47 $ 3.10 $ 5.67 Diluted Earnings per Share Net Income attributable to DTE Energy — continuing operations $ 58 $ 372 $ 495 $ 844 Less: Allocation of earnings to net restricted stock awards — 1 1 2 $ 58 $ 371 $ 494 $ 842 Net Income (Loss) attributable to DTE Energy — discontinued operations (33) 104 106 249 Net income available to common shareholders — diluted $ 25 $ 475 $ 600 $ 1,091 Average number of common shares outstanding — basic 193 193 193 192 Average dilutive equity units, performance share awards, and stock options 1 — 1 1 Average number of common shares outstanding — diluted 194 193 194 193 Income from continuing operations $ 0.30 $ 1.92 $ 2.55 $ 4.37 Income (loss) from discontinued operations (0.17) 0.54 0.55 1.29 Diluted Earnings per Common Share (a) $ 0.13 $ 2.46 $ 3.10 $ 5.66 _______________________________________ (a) Equity Units excluded from the calculation of diluted EPS were approximately 11.1 million and 10.3 million for the three months ended September 30, 2021 and 2020, respectively, and 11.5 million and 10.3 million for the nine months ended September 30, 2021 and 2020, respectively, as the dilutive stock price threshold was not met.

Fair Value (Tables)

Fair Value (Tables)	9 Months Ended
Fair Value (Tables)	Sep. 30, 2021
Fair Value Disclosures [Abstract]
Assets and Liabilities Measured and Recorded at Fair Value on a Recurring Basis	The following table presents assets and liabilities for DTE Energy measured and recorded at fair value on a recurring basis: September 30, 2021 December 31, 2020 Level Level Level Other (a) Netting (b) Net Balance Level Level Level Other (a) Netting (b) Net Balance (In millions) Assets Cash equivalents (c) $ 9 $ — $ — $ — $ — $ 9 $ 438 $ — $ — $ — $ — $ 438 Nuclear decommissioning trusts Equity securities 944 — — 196 — 1,140 947 — — 222 — 1,169 Fixed income securities 127 429 — 102 — 658 102 371 — 82 — 555 Private equity and other — — — 175 — 175 — — — 104 — 104 Cash equivalents 34 — — — — 34 27 — — — — 27 Other investments (d) Equity securities 61 — — — — 61 55 — — — — 55 Fixed income securities 7 — — — — 7 8 — — — — 8 Cash equivalents 86 — — — — 86 97 — — — — 97 Derivative assets Commodity contracts (e) Natural gas 579 146 53 — (715) 63 99 74 60 — (156) 77 Electricity — 707 245 — (627) 325 — 128 52 — (120) 60 Environmental & Other — 598 12 — (570) 40 — 150 4 — (135) 19 Total derivative assets 579 1,451 310 — (1,912) 428 99 352 116 — (411) 156 Total $ 1,847 $ 1,880 $ 310 $ 473 $ (1,912) $ 2,598 $ 1,773 $ 723 $ 116 $ 408 $ (411) $ 2,609 Liabilities Derivative liabilities Commodity contracts (e) Natural gas $ (425) $ (297) $ (333) $ — $ 664 $ (391) $ (88) $ (59) $ (76) $ — $ 151 $ (72) Electricity — (576) (340) — 614 (302) — (126) (42) — 125 (43) Environmental & Other — (581) — — 570 (11) — (137) — — 129 (8) Foreign currency exchange contracts — (5) — — — (5) — (5) — — (5) Total $ (425) $ (1,459) $ (673) $ — $ 1,848 $ (709) $ (88) $ (327) $ (118) $ — $ 405 $ (128) Net Assets (Liabilities) at end of period $ 1,422 $ 421 $ (363) $ 473 $ (64) $ 1,889 $ 1,685 $ 396 $ (2) $ 408 $ (6) $ 2,481 Assets Current $ 506 $ 1,183 $ 258 $ — $ (1,591) $ 356 $ 532 $ 260 $ 92 $ — $ (330) $ 554 Noncurrent 1,341 697 52 473 (321) 2,242 1,241 463 24 408 (81) 2,055 Total Assets $ 1,847 $ 1,880 $ 310 $ 473 $ (1,912) $ 2,598 $ 1,773 $ 723 $ 116 $ 408 $ (411) $ 2,609 Liabilities Current $ (409) $ (1,138) $ (464) $ — $ 1,546 $ (465) $ (84) $ (223) $ (79) $ — $ 318 $ (68) Noncurrent (16) (321) (209) — 302 (244) (4) (104) (39) — 87 (60) Total Liabilities $ (425) $ (1,459) $ (673) $ — $ 1,848 $ (709) $ (88) $ (327) $ (118) $ — $ 405 $ (128) Net Assets (Liabilities) at end of period $ 1,422 $ 421 $ (363) $ 473 $ (64) $ 1,889 $ 1,685 $ 396 $ (2) $ 408 $ (6) $ 2,481 _______________________________________ (a) Amounts represent assets valued at NAV as a practical expedient for fair value. (b) Amounts represent the impact of master netting agreements that allow DTE Energy to net gain and loss positions and cash collateral held or placed with the same counterparties. (c) Amounts consisted of $1 million and $2 million of cash equivalents included in Restricted cash on DTE Energy's Consolidated Statements of Financial Position at September 30, 2021 and December 31, 2020, respectively. All other amounts are included in Cash and cash equivalents on the Consolidated Statements of Financial Position. (d) Excludes cash surrender value of life insurance investments. (e) For contracts with a clearing agent, DTE Energy nets all activity across commodities. This can result in some individual commodities having a contra balance. The following table presents assets for DTE Electric measured and recorded at fair value on a recurring basis as of: September 30, 2021 December 31, 2020 Level 1 Level 2 Level 3 Other (a) Net Balance Level 1 Level 2 Level 3 Other (a) Net Balance (In millions) Assets Cash equivalents $ — $ — $ — $ — $ — $ 4 $ — $ — $ — $ 4 Nuclear decommissioning trusts Equity securities 944 — — 196 1,140 947 — — 222 1,169 Fixed income securities 127 429 — 102 658 102 371 — 82 555 Private equity and other — — — 175 175 — — — 104 104 Cash equivalents 34 — — — 34 27 — — — 27 Other investments Equity securities 18 — — — 18 16 — — — 16 Cash equivalents 11 — — — 11 11 — — — 11 Derivative assets — FTRs — — 12 — 12 — — 4 — 4 Total $ 1,134 $ 429 $ 12 $ 473 $ 2,048 $ 1,107 $ 371 $ 4 $ 408 $ 1,890 Assets Current $ — $ — $ 12 $ — $ 12 $ 4 $ — $ 4 $ — $ 8 Noncurrent 1,134 429 — 473 2,036 1,103 371 — 408 1,882 Total Assets $ 1,134 $ 429 $ 12 $ 473 $ 2,048 $ 1,107 $ 371 $ 4 $ 408 $ 1,890 _______________________________________ (a) Amounts represent assets valued at NAV as a practical expedient for fair value.
Reconciliation of Level 3 Assets and Liabilities Measured at Fair Value on a Recurring Basis	The following table presents the fair value reconciliation of Level 3 assets and liabilities measured at fair value on a recurring basis for DTE Energy: Three Months Ended September 30, 2021 Three Months Ended September 30, 2020 Natural Gas Electricity Other Total Natural Gas Electricity Other Total (In millions) Net Assets (Liabilities) as of June 30 $ (181) $ (49) $ 15 $ (215) $ 20 $ 16 $ 10 $ 46 Transfers from Level 3 into Level 2 — — — — (1) — — (1) Total gains (losses) Included in earnings (a) (162) (21) — (183) (80) 37 1 (42) Recorded in Regulatory liabilities — — (1) (1) — — 9 9 Purchases, issuances, and settlements Settlements 63 (25) (2) 36 22 (48) (13) (39) Net Assets (Liabilities) as of September 30 $ (280) $ (95) $ 12 $ (363) $ (39) $ 5 $ 7 $ (27) Total gains (losses) included in Net Income attributed to the change in unrealized gains (losses) related to assets and liabilities held at September 30 (a) $ (109) $ (30) $ (2) $ (141) $ (57) $ 11 $ (1) $ (47) _______________________________________ (a) Amounts are reflected in Operating Revenues — Non-utility operations and Fuel, purchased power, gas, and other — non-utility in DTE Energy's Consolidated Statements of Operations. Nine Months Ended September 30, 2021 Nine Months Ended September 30, 2020 Natural Gas Electricity Other Total Natural Gas Electricity Other Total (In millions) Net Assets (Liabilities) as of December 31 $ (16) $ 10 $ 4 $ (2) $ (15) $ 16 $ 3 $ 4 Transfers from Level 3 into Level 2 — — — — (5) — — (5) Total gains (losses) Included in earnings (a) (356) (5) — (361) (44) 90 (7) 39 Recorded in Regulatory liabilities — — 14 14 — — 21 21 Purchases, issuances, and settlements Settlements 92 (100) (6) (14) 25 (101) (10) (86) Net Assets (Liabilities) as of September 30 $ (280) $ (95) $ 12 $ (363) $ (39) $ 5 $ 7 $ (27) Total gains (losses) included in Net Income attributed to the change in unrealized gains (losses) related to assets and liabilities held at September 30 (a) $ (301) $ (54) $ (17) $ (372) $ (20) $ 53 $ (17) $ 16 Total gains (losses) included in Regulatory liabilities attributed to the change in unrealized gains (losses) related to assets and liabilities held at September 30 $ — $ — $ 12 $ 12 $ — $ — $ 7 $ 7 _______________________________________ (a) Amounts are reflected in Operating Revenues — Non-utility operations and Fuel, purchased power, gas, and other — non-utility in DTE Energy's Consolidated Statements of Operations. The following table presents the fair value reconciliation of Level 3 assets and liabilities measured at fair value on a recurring basis for DTE Electric: Three Months Ended September 30, Nine Months Ended September 30, 2021 2020 2021 2020 (In millions) Net Assets as of beginning of period $ 15 $ 10 $ 4 $ 3 Change in fair value recorded in Regulatory liabilities (1) 9 14 21 Purchases, issuances, and settlements Settlements (2) (12) (6) (17) Net Assets as of September 30 $ 12 $ 7 $ 12 $ 7 Total gains (losses) included in Regulatory liabilities attributed to the change in unrealized gains (losses) related to assets and liabilities held at September 30 $ — $ — $ 12 $ 7
Unobservable Inputs Related to Level 3 Assets and Liabilities	The following tables present the unobservable inputs related to DTE Energy's Level 3 assets and liabilities: September 30, 2021 Commodity Contracts Derivative Assets Derivative Liabilities Valuation Techniques Unobservable Input Range Weighted Average (In millions) Natural Gas $ 53 $ (333) Discounted Cash Flow Forward basis price (per MMBtu) $ (1.33) — $ 3.53 /MMBtu $ (0.04) /MMBtu Electricity $ 245 $ (340) Discounted Cash Flow Forward basis price (per MWh) $ (8) — $ 10 /MWh $ (1) /MWh December 31, 2020 Commodity Contracts Derivative Assets Derivative Liabilities Valuation Techniques Unobservable Input Range Weighted Average (In millions) Natural Gas $ 60 $ (76) Discounted Cash Flow Forward basis price (per MMBtu) $ (0.86) — $ 2.50 /MMBtu $ (0.07) /MMBtu Electricity $ 52 $ (42) Discounted Cash Flow Forward basis price (per MWh) $ (9) — $ 6 /MWh $ — /MWh
Carrying Amount of Fair Value of Financial Instruments	The following table presents the carrying amount and fair value of financial instruments for DTE Energy: September 30, 2021 December 31, 2020 Carrying Fair Value Carrying Fair Value Amount Level 1 Level 2 Level 3 Amount Level 1 Level 2 Level 3 (In millions) Notes receivable (a) , excluding lessor finance leases $ 142 $ — $ — $ 142 $ 141 $ — $ — $ 141 Short-term borrowings $ 361 $ — $ 361 $ — $ 38 $ — $ 38 $ — Notes payable (b) $ 5 $ — $ — $ 5 $ 19 $ — $ — $ 19 Long-term debt (c) $ 17,222 $ 2,241 $ 15,486 $ 1,104 $ 19,439 $ 2,547 $ 18,230 $ 1,397 _______________________________________ (a) Current portion included in Current Assets — Other on DTE Energy's Consolidated Statements of Financial Position. (b) Included in Current Liabilities — Other and Other Liabilities — Other on DTE Energy's Consolidated Statements of Financial Position. (c) Includes debt due within one year and excludes finance lease obligations. Carrying value also includes unamortized debt discounts and issuance costs. The following table presents the carrying amount and fair value of financial instruments for DTE Electric: September 30, 2021 December 31, 2020 Carrying Fair Value Carrying Fair Value Amount Level 1 Level 2 Level 3 Amount Level 1 Level 2 Level 3 (In millions) Notes receivable (a) $ 17 $ — $ — $ 17 $ 16 $ — $ — $ 16 Short-term borrowings — affiliates $ 32 $ — $ — $ 32 $ 101 $ — $ — $ 101 Short-term borrowings — other $ 159 $ — $ 159 $ — $ — $ — $ — $ — Notes payable (b) $ 4 $ — $ — $ 4 $ 17 $ — $ — $ 17 Long-term debt (c) $ 8,906 $ — $ 9,952 $ 150 $ 8,236 $ — $ 9,579 $ 379 _______________________________________ (a) Included in Current Assets — Other on DTE Electric's Consolidated Statements of Financial Position. (b) Included in Current Liabilities — Other and Other Liabilities — Other on DTE Electric's Consolidated Statements of Financial Position. (c) Includes debt due within one year and excludes finance lease obligations. Carrying value also includes unamortized debt discounts and issuance costs.
Fair Value of Nuclear Decommissioning Trust Fund Assets	The following table summarizes DTE Electric's fair value of the nuclear decommissioning trust fund assets: September 30, 2021 December 31, 2020 (In millions) Fermi 2 $ 1,989 $ 1,841 Fermi 1 3 3 Low-level radioactive waste 15 11 $ 2,007 $ 1,855
Schedule of Realized Gains and Losses and Proceeds from Sale of Securities by Nuclear Decommissioning Trust Funds	The following table sets forth DTE Electric's gains and losses and proceeds from the sale of securities by the nuclear decommissioning trust funds: Three Months Ended September 30, Nine Months Ended September 30, 2021 2020 2021 2020 (In millions) Realized gains $ 21 $ 38 $ 80 $ 172 Realized losses $ (1) $ (11) $ (9) $ (103) Proceeds from sale of securities $ 217 $ 816 $ 854 $ 2,054
Fair Value and Unrealized Gains and Losses for Nuclear Decommissioning Trust Funds	The following table sets forth DTE Electric's fair value and unrealized gains and losses for the nuclear decommissioning trust funds: September 30, 2021 December 31, 2020 Fair Unrealized Unrealized Fair Unrealized Unrealized (In millions) Equity securities $ 1,140 $ 507 $ (8) $ 1,169 $ 481 $ (6) Fixed income securities 658 24 (5) 555 20 (1) Private equity and other 175 41 (2) 104 — — Cash equivalents 34 — — 27 — — $ 2,007 $ 572 $ (15) $ 1,855 $ 501 $ (7)
Fair Value of the Fixed Income Securities Held in Nuclear Decommissioning Trust Funds	The following table summarizes the fair value of the fixed income securities held in nuclear decommissioning trust funds by contractual maturity: September 30, 2021 (In millions) Due within one year $ 11 Due after one through five years 138 Due after five through ten years 112 Due after ten years 295 $ 556
Summary of Gains (Losses) Related to the Trust	The following table summarizes the Registrant's gains (losses) related to the trust: Three Months Ended September 30, Nine Months Ended September 30, 2021 2020 2021 2020 (In millions) Gains (losses) related to equity securities $ (1) $ 2 $ 3 $ (4) Gains (losses) related to fixed income securities — — — (3) $ (1) $ 2 $ 3 $ (7)

Financial and Other Derivativ_2

Financial and Other Derivative Instruments (Tables)	9 Months Ended
Financial and Other Derivative Instruments (Tables)	Sep. 30, 2021
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Fair Value of Derivative Instruments	The following table presents the fair value of derivative instruments for DTE Energy: September 30, 2021 December 31, 2020 Derivative Derivative Liabilities Derivative Derivative Liabilities (In millions) Derivatives designated as hedging instruments Foreign currency exchange contracts $ — $ (3) $ — $ (4) Derivatives not designated as hedging instruments Commodity contracts Natural gas $ 778 $ (1,055) $ 233 $ (223) Electricity 952 (916) 180 (168) Environmental & Other 610 (581) 154 (137) Foreign currency exchange contracts — (2) — (1) Total derivatives not designated as hedging instruments $ 2,340 $ (2,554) $ 567 $ (529) Current $ 1,938 $ (2,011) $ 446 $ (386) Noncurrent 402 (546) 121 (147) Total derivatives $ 2,340 $ (2,557) $ 567 $ (533) The following table presents the fair value of derivative instruments for DTE Electric: September 30, 2021 December 31, 2020 (In millions) FTRs — Other current assets $ 12 $ 4 Total derivatives not designated as hedging instruments $ 12 $ 4
Offsetting Assets	The following table presents net cash collateral offsetting arrangements for DTE Energy: September 30, 2021 December 31, 2020 (In millions) Cash collateral netted against Derivative assets $ (122) $ (12) Cash collateral netted against Derivative liabilities 58 6 Cash collateral recorded in Accounts receivable (a) 66 14 Cash collateral recorded in Accounts payable (a) (8) (1) Total net cash collateral posted (received) $ (6) $ 7 _______________________________________ (a) Amounts are recorded net by counterparty. The following table presents the netting offsets of Derivative assets and liabilities for DTE Energy: September 30, 2021 December 31, 2020 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 $ 778 $ (715) $ 63 $ 233 $ (156) $ 77 Electricity 952 (627) 325 180 (120) 60 Environmental & Other 610 (570) 40 154 (135) 19 Total derivative assets $ 2,340 $ (1,912) $ 428 $ 567 $ (411) $ 156 Derivative liabilities Commodity contracts Natural gas $ (1,055) $ 664 $ (391) $ (223) $ 151 $ (72) Electricity (916) 614 (302) (168) 125 (43) Environmental & Other (581) 570 (11) (137) 129 (8) Foreign currency exchange contracts (5) — (5) (5) — (5) Total derivative liabilities $ (2,557) $ 1,848 $ (709) $ (533) $ 405 $ (128)
Offsetting Liabilities	The following table presents net cash collateral offsetting arrangements for DTE Energy: September 30, 2021 December 31, 2020 (In millions) Cash collateral netted against Derivative assets $ (122) $ (12) Cash collateral netted against Derivative liabilities 58 6 Cash collateral recorded in Accounts receivable (a) 66 14 Cash collateral recorded in Accounts payable (a) (8) (1) Total net cash collateral posted (received) $ (6) $ 7 _______________________________________ (a) Amounts are recorded net by counterparty. The following table presents the netting offsets of Derivative assets and liabilities for DTE Energy: September 30, 2021 December 31, 2020 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 $ 778 $ (715) $ 63 $ 233 $ (156) $ 77 Electricity 952 (627) 325 180 (120) 60 Environmental & Other 610 (570) 40 154 (135) 19 Total derivative assets $ 2,340 $ (1,912) $ 428 $ 567 $ (411) $ 156 Derivative liabilities Commodity contracts Natural gas $ (1,055) $ 664 $ (391) $ (223) $ 151 $ (72) Electricity (916) 614 (302) (168) 125 (43) Environmental & Other (581) 570 (11) (137) 129 (8) Foreign currency exchange contracts (5) — (5) (5) — (5) Total derivative liabilities $ (2,557) $ 1,848 $ (709) $ (533) $ 405 $ (128)
Netting Offsets of Derivative Assets and Liabilities Reconciliation to the Statements of Financial Position	The following table presents the netting offsets of Derivative assets and liabilities showing the reconciliation of derivative instruments to DTE Energy's Consolidated Statements of Financial Position: September 30, 2021 December 31, 2020 Derivative Assets Derivative Liabilities Derivative Assets Derivative Liabilities Current Noncurrent Current Noncurrent Current Noncurrent Current Noncurrent (In millions) Total fair value of derivatives $ 1,938 $ 402 $ (2,011) $ (546) $ 446 $ 121 $ (386) $ (147) Counterparty netting (1,498) (292) 1,498 292 (318) (81) 318 81 Collateral adjustment (93) (29) 48 10 (12) — — 6 Total derivatives as reported $ 347 $ 81 $ (465) $ (244) $ 116 $ 40 $ (68) $ (60)
Gain (Loss) Recognized in Income on Derivatives	The effect of derivatives not designated as hedging instruments on DTE Energy's Consolidated Statements of Operations is as follows: Location of Gain (Loss) Recognized in Income on Derivatives Gain (Loss) Recognized in Income on Derivatives for the Three Months Ended September 30, Gain (Loss) Recognized in Income on Derivatives for the Nine Months Ended September 30, 2021 2020 2021 2020 (In millions) Commodity contracts Natural gas Operating Revenues — Non-utility operations $ (214) $ (27) $ (371) $ (63) Natural gas Fuel, purchased power, gas, and other — non-utility 63 (51) (16) 28 Electricity Operating Revenues — Non-utility operations 68 33 143 75 Environmental & Other Operating Revenues — Non-utility operations 3 2 (36) (40) Foreign currency exchange contracts Operating Revenues — Non-utility operations 2 (2) (1) — Total $ (78) $ (45) $ (281) $ —
Volume of Commodity Contracts	The following represents the cumulative gross volume of DTE Energy's derivative contracts outstanding as of September 30, 2021: Commodity Number of Units Natural gas (MMBtu) 2,096,409,912 Electricity (MWh) 29,383,562 Foreign currency exchange ($ CAD) 119,281,865 Renewable Energy Certificates (MWh) 8,387,594 Carbon emissions (Metric Tons) 48,343,793

Long-Term Debt (Tables)

Long-Term Debt (Tables)	9 Months Ended
Long-Term Debt (Tables)	Sep. 30, 2021
Debt Disclosure [Abstract]
Schedule of Debt Issuances	In 2021, the following debt was issued: Company Month Type Interest Rate Maturity Date Amount (In millions) DTE Electric March Mortgage bonds (a) 1.90% 2028 $ 575 DTE Electric March Mortgage bonds (a) 3.25% 2051 425 DT Midstream June Senior notes (b) 4.125% 2029 1,100 DT Midstream June Senior notes (b) 4.375% 2031 1,000 DT Midstream June Term loan facility (b) Variable 2028 1,000 $ 4,100 _______________________________________ (a) Bonds were issued as Green Bonds and the proceeds will be used to finance qualified expenditures for solar and wind energy, payments under power purchase agreements for solar and wind energy, and energy optimization programs. (b) Proceeds were used for the repayment of short-term borrowings due to DTE Energy to facilitate the separation of DT Midstream, as well as a one-time special dividend provided to DTE Energy. The debt was transferred to DT Midstream upon its separation on July 1, 2021. Refer to Note 4 to the Consolidated Financial Statements, “Dispositions and Impairments,” for additional information and to the Debt Redemptions section below for DTE Energy's use of the proceeds received from DT Midstream.
Schedule of Debt Redemptions	In 2021, the following debt was redeemed: Company Month Type Interest Rate Maturity Date Amount (In millions) DTE Electric April Mortgage bonds 3.90% 2021 $ 250 DTE Electric May Mortgage bonds 7.00% 2021 33 DTE Energy June Junior subordinated debentures (a) 5.375% 2076 300 DTE Energy July Senior notes 3.30% 2022 300 DTE Energy July Senior notes 2.60% 2022 300 DTE Energy July Senior notes 3.70% 2023 600 DTE Energy July Senior notes 3.85% 2023 135 DTE Energy July Senior notes 3.50% 2024 350 DTE Energy July Senior notes 3.80% 2027 350 DTE Energy July Senior notes 3.40% 2029 21 DTE Energy July Senior notes 6.375% 2033 191 DTE Energy August Senior notes 3.85% 2023 165 DTE Energy August Senior notes 6.375% 2033 209 DTE Electric August Mortgage bonds 6.90% 2021 38 $ 3,242 _______________________________________ (a) Early redemption resulted in a loss on extinguishment of debt of $8 million relating to the write-off of unamortized issuance costs.

Short-Term Credit Arrangement_2

Short-Term Credit Arrangements and Borrowings (Tables)	9 Months Ended
Short-Term Credit Arrangements and Borrowings (Tables)	Sep. 30, 2021
Short-term Debt [Abstract]
Schedule of Line of Credit Facilities	The availability under these facilities as of September 30, 2021 is shown in the following table: DTE Energy DTE Electric DTE Gas Total (In millions) Unsecured revolving credit facility, expiring April 2025 (a) $ 1,500 $ 500 $ 300 $ 2,300 Unsecured Canadian revolving credit facility, expiring May 2023 87 — — 87 Unsecured letter of credit facility, expiring in February 2023 150 — — 150 Unsecured letter of credit facility, expiring in July 2023 70 — — 70 Unsecured letter of credit facility (b) 50 — — 50 1,857 500 300 2,657 Amounts outstanding at September 30, 2021 Revolver borrowings 74 — — 74 Commercial paper issuances — 159 128 287 Letters of credit 268 — — 268 342 159 128 629 Net availability at September 30, 2021 $ 1,515 $ 341 $ 172 $ 2,028 _______________________________________ (a) Total availability of $102 million expires in April 2024, including $67 million at DTE Energy, $22 million at DTE Electric, and $13 million at DTE Gas. All other availability expires in April 2025. (b) Uncommitted letter of credit facility with automatic renewal provision for each July and therefore no expiration.

Leases (Tables)

Leases (Tables)	9 Months Ended
Leases (Tables)	Sep. 30, 2021
Leases [Abstract]
Components of Net Investment in Finance Leases	The components of DTE Energy’s net investment in finance leases for remaining periods were as follows: DTE Energy September 30, 2021 (In millions) 2021 $ 6 2022 22 2023 22 2024 22 2025 22 2026 and Thereafter 292 Total minimum future lease receipts 386 Residual value of leased pipeline 17 Less unearned income 202 Net investment in finance lease 201 Less current portion 7 $ 194
Schedule of Lease Income Associated with Operating Leases	DTE Energy’s lease income associated with operating leases, including the line items in which it was included on the Consolidated Statements of Operations, was as follows: Three Months Ended September 30, Nine Months Ended September 30, 2021 2020 2021 2020 (In millions) Fixed payments $ 13 $ 14 $ 42 $ 43 Variable payments 55 43 90 82 $ 68 $ 57 $ 132 $ 125 Operating revenues $ 26 $ 26 $ 70 $ 74 Other income 42 31 62 51 $ 68 $ 57 $ 132 $ 125

Retirement Benefits and Trust_2

Retirement Benefits and Trusteed Assets (Tables)	9 Months Ended
Retirement Benefits and Trusteed Assets (Tables)	Sep. 30, 2021
Retirement Benefits [Abstract]
Schedule of Net Periodic Benefit Costs (Credits)	The following tables detail the components of net periodic benefit costs (credits) for pension benefits and other postretirement benefits for DTE Energy: Pension Benefits Other Postretirement Benefits Three Months Ended September 30, 2021 2020 2021 2020 (In millions) Service cost $ 27 $ 25 $ 8 $ 7 Interest cost 39 46 12 14 Expected return on plan assets (84) (84) (33) (32) Amortization of: Net actuarial loss 49 43 3 4 Prior service credit — — (5) (5) Settlements — 2 — — Net periodic benefit cost (credit) $ 31 $ 32 $ (15) $ (12) Pension Benefits Other Postretirement Benefits Nine Months Ended September 30, 2021 2020 2021 2020 (In millions) Service cost $ 81 $ 74 $ 23 $ 20 Interest cost 118 139 35 42 Expected return on plan assets (254) (250) (97) (96) Amortization of: Net actuarial loss 147 129 10 12 Prior service credit — — (15) (15) Settlements — 2 — — Net periodic benefit cost (credit) $ 92 $ 94 $ (44) $ (37) The following tables detail the components of net periodic benefit costs (credits) for other postretirement benefits for DTE Electric: Three Months Ended September 30, Nine Months Ended September 30, 2021 2020 2021 2020 (In millions) Service cost $ 6 $ 5 $ 17 $ 15 Interest cost 8 11 25 32 Expected return on plan assets (22) (21) (65) (65) Amortization of: Net actuarial loss 3 2 9 8 Prior service credit (3) (3) (10) (10) Net periodic benefit credit $ (8) $ (6) $ (24) $ (20)

Segment and Related Informati_2

Segment and Related Information (Tables)	9 Months Ended
Segment and Related Information (Tables)	Sep. 30, 2021
Segment Reporting [Abstract]
Financial Data of Business Segments	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, natural gas sales, and renewable natural gas sales in the following segments: Three Months Ended September 30, Nine Months Ended September 30, 2021 2020 2021 2020 (In millions) Electric $ 17 $ 16 $ 48 $ 46 Gas 3 4 10 12 DTE Vantage 125 134 463 308 Energy Trading 9 9 35 23 Corporate and Other 1 1 2 2 $ 155 $ 164 $ 558 $ 391 Financial data of DTE Energy's business segments follows: Three Months Ended September 30, Nine Months Ended September 30, 2021 2020 2021 2020 (In millions) Operating Revenues — Utility operations Electric $ 1,700 $ 1,690 $ 4,468 $ 4,211 Gas 193 173 1,070 964 Operating Revenues — Non-utility operations Electric 2 3 9 10 DTE Vantage 372 324 1,132 850 Energy Trading 1,602 1,061 4,208 2,714 Corporate and Other 1 1 2 2 Reconciliation and Eliminations (a) (155) (172) (572) (408) Total $ 3,715 $ 3,080 $ 10,317 $ 8,343 _______________________________________ (a) Includes $14 million for the nine months ended September 30, 2021 and $8 million and $17 million for the three and nine months ended September 30, 2020, respectively, for eliminations related to DTE Energy's prior Gas Storage and Pipelines segment that remain in continuing operations. Eliminations for these revenues are offset by related cost eliminations and have no impact on DTE Energy net income. Three Months Ended September 30, Nine Months Ended September 30, 2021 2020 2021 2020 (In millions) Net Income (Loss) Attributable to DTE Energy by Segment: Electric $ 342 $ 398 $ 788 $ 675 Gas (30) (20) 146 102 DTE Vantage 73 47 115 102 Energy Trading (52) (28) (173) 5 Corporate and Other (275) (25) (381) (40) Discontinued Operations (33) 104 106 249 Net Income Attributable to DTE Energy Company $ 25 $ 476 $ 601 $ 1,093

Organization and Basis of Pre_3

Organization and Basis of Presentation (Details Textuals) customer in Millions, $ in Millions	Sep. 30, 2021USD ($)customer
Variable Interest Entity [Line Items]
Number of electric utility customers \| customer	2.3
Number of gas utility customers \| customer	1.3
Material potential exposure \| $	$ 0
DTE Electric
Variable Interest Entity [Line Items]
Material potential exposure \| $	$ 0

Organization and Basis of Pre_4

Organization and Basis of Presentation (Consolidated Variable Interest Entities) (Details) - USD ($) $ in Millions	Sep. 30, 2021	Dec. 31, 2020
ASSETS
Cash and cash equivalents	$ 54	$ 472
Accounts receivable	1,522	1,542
Property, plant, and equipment, net	26,157	24,499
Total Assets	39,435	45,496
LIABILITIES
Accounts payable	1,365	1,000
Short-term borrowings	361	38
Variable interest entity, primary beneficiary
ASSETS
Cash and cash equivalents	23	20
Accounts receivable	26	28
Inventories	45	107
Property, plant, and equipment, net	5	14
Notes receivable and other	67	33
Total Assets	166	202
LIABILITIES
Accounts payable	21	22
Short-term borrowings	74	38
Other current and long-term liabilities	2	4
Total liabilities	$ 97	$ 64

Organization and Basis of Pre_5

Organization and Basis of Presentation (Non-Consolidated Variable Interest Entities) (Details) - USD ($) $ in Millions	Sep. 30, 2021	Dec. 31, 2020
Variable Interest Entity [Line Items]
Investments in equity method investees	$ 186	$ 177
Notes receivable	304	261
Variable interest entity, non-consolidated
Variable Interest Entity [Line Items]
Investments in equity method investees	170	159
Notes receivable	16	21
Future funding commitments	$ 3	$ 6

Significant Accounting Polici_4

Significant Accounting Policies (Other Income) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Schedule of Other Nonoperating Income, by Component [Line Items]
Income from REF entities	$ 57	$ 43	$ 102	$ 95
Equity earnings of equity method investees	17	12	31	21
Contract services	6	7	21	20
Allowance for equity funds used during construction	7	6	20	19
Gains from rabbi trust securities	0	2	4	24
Other	3	5	9	9
Total other income	90	75	187	188
DTE Electric
Schedule of Other Nonoperating Income, by Component [Line Items]
Contract services	6	7	21	20
Allowance for equity funds used during construction	6	6	18	18
Gains from rabbi trust securities	0	2	4	24
Other	2	3	9	6
Total other income	$ 14	$ 18	$ 52	$ 68

Significant Accounting Polici_5

Significant Accounting Policies (Income Taxes) (Details)	3 Months Ended		9 Months Ended
Significant Accounting Policies (Income Taxes) (Details)	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Schedule of Income Taxes [Line Items]
Effective Tax Rate	186.00%	5.00%	(34.00%)	2.00%
DTE Electric
Schedule of Income Taxes [Line Items]
Effective Tax Rate	12.00%	13.00%	10.00%	12.00%

Significant Accounting Polici_6

Significant Accounting Policies (Details Textuals) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020	Dec. 31, 2020
Significant Accounting Policies [Line Items]
Reduction in accumulated other comprehensive loss due to the Separation of DT Midstream	$ (3,999)
Effective tax rate increase (decrease)	181.00%		(36.00%)
Effective tax rate increase (decrease) due to deferred tax remeasurement	133.00%		(23.00%)
Effective tax rate increase (decrease) due to annual production tax credits	51.00%		(13.00%)
Effective tax rate increase (decrease) due to amortization of TCJA regulatory liability	35.00%		(9.00%)
Effective tax rate increase (decrease) due to valuation allowance	(29.00%)		4.00%
Effective tax rate increase (decrease) due to deferred intercompany gain	(13.00%)		2.00%
Effective tax rate increase (decrease) due to net operating losses due to the CARES Act			4.00%
Effective tax rate increase (decrease) due to West Virginia tax law change			2.00%
Deferred tax expense for valuation allowance established	$ 18		$ 18
Deferred tax benefit for deferred tax remeasurement	85		85
Deferred tax expense for deferred intercompany gain recognized	9		9
Unrecognized compensation cost	76		$ 76
Recognition period (in years)			1 year 4 months 24 days
Specific review of probable future collections based on receivable balances, threshold duration			30 days
Past due
Significant Accounting Policies [Line Items]
Financing receivables	$ 0		$ 0
Minimum
Significant Accounting Policies [Line Items]
Notes receivable considered delinquent period			60 days
Maximum
Significant Accounting Policies [Line Items]
Notes receivable considered delinquent period			120 days
DTE Electric and DTE Gas
Significant Accounting Policies [Line Items]
Receivables due date			21 days
Threshold period past due for write-off of trade accounts receivable			150 days
DTE Electric
Significant Accounting Policies [Line Items]
Effective tax rate increase (decrease)	(1.00%)		(2.00%)
Effective tax rate increase (decrease) due to annual production tax credits			(1.00%)
Effective tax rate increase (decrease) due to amortization of TCJA regulatory liability			(1.00%)
DTE Electric \| DTE Energy
Significant Accounting Policies [Line Items]
Income tax receivable	$ 11		$ 11		$ 8
Allocated costs	10	$ 12	$ 35	$ 28
Accumulated Other Comprehensive Loss
Significant Accounting Policies [Line Items]
Reduction in accumulated other comprehensive loss due to the Separation of DT Midstream	$ 10

Significant Accounting Polici_7

Significant Accounting Policies (Financing Receivables Classified by Internal Grade of Credit Risk) (Details) $ in Millions	Sep. 30, 2021USD ($)
Notes receivable
Financing Receivable, Credit Quality Indicator [Line Items]
2021	$ 2
2020	100
2019 and Prior	40
Total	142
Notes receivable \| DTE Electric
Financing Receivable, Credit Quality Indicator [Line Items]
Total	17
Notes receivable \| Internal grade 1
Financing Receivable, Credit Quality Indicator [Line Items]
2021	0
2020	0
2019 and Prior	19
Total	19
Notes receivable \| Internal grade 1 \| DTE Electric
Financing Receivable, Credit Quality Indicator [Line Items]
Total	14
Notes receivable \| Internal grade 2
Financing Receivable, Credit Quality Indicator [Line Items]
2021	2
2020	100
2019 and Prior	21
Total	123
Notes receivable \| Internal grade 2 \| DTE Electric
Financing Receivable, Credit Quality Indicator [Line Items]
Total	3
Notes receivable \| Internal grade 3
Financing Receivable, Credit Quality Indicator [Line Items]
2021	0
2020	0
2019 and Prior	0
Total	0
Notes receivable \| Internal grade 3 \| DTE Electric
Financing Receivable, Credit Quality Indicator [Line Items]
Total	0
Net investment in leases
Financing Receivable, Credit Quality Indicator [Line Items]
2021	0
2020	161
2019 and Prior	40
Total	201
Net investment in leases \| DTE Electric
Financing Receivable, Credit Quality Indicator [Line Items]
Total	0
Net investment in leases \| Internal grade 1
Financing Receivable, Credit Quality Indicator [Line Items]
2021	0
2020	2
2019 and Prior	39
Total	41
Net investment in leases \| Internal grade 1 \| DTE Electric
Financing Receivable, Credit Quality Indicator [Line Items]
Total	0
Net investment in leases \| Internal grade 2
Financing Receivable, Credit Quality Indicator [Line Items]
2021	0
2020	159
2019 and Prior	1
Total	160
Net investment in leases \| Internal grade 2 \| DTE Electric
Financing Receivable, Credit Quality Indicator [Line Items]
Total	$ 0

Significant Accounting Polici_8

Significant Accounting Policies (Roll-Forward of Activity for Financing Receivables Credit Loss Reserves) (Details) - USD ($) $ in Millions	9 Months Ended	12 Months Ended
	Sep. 30, 2021	Dec. 31, 2020	Jan. 01, 2020
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	$ 104	$ 83
Current period provision	42	105
Write-offs charged against allowance	(93)	(134)
Recoveries of amounts previously written off	49	50
Ending balance	102	104
DTE Electric
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	57	46
Current period provision	27	61
Write-offs charged against allowance	(58)	(80)
Recoveries of amounts previously written off	29	30
Ending balance	55	57
Trade accounts receivable
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	101	79
Current period provision	41	102
Write-offs charged against allowance	(92)	(130)
Recoveries of amounts previously written off	49	50
Ending balance	99	101
Trade accounts receivable \| Discontinued operations, spinoff \| DT Midstream
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Trade accounts receivable reserve related to discontinued operations			$ 8
Other receivables
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	3	4
Current period provision	1	3
Write-offs charged against allowance	(1)	(4)
Recoveries of amounts previously written off	0	0
Ending balance	$ 3	$ 3

Significant Accounting Polici_9

Significant Accounting Policies (Uncollectible Expense) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Accounts, Notes, Loans and Financing Receivable [Line Items]
Uncollectible expense	$ 7	$ 22	$ 42	$ 72
DTE Electric
Accounts, Notes, Loans and Financing Receivable [Line Items]
Uncollectible expense	$ 10	$ 16	$ 26	$ 42

Dispositions and Impairments (D

Dispositions and Impairments (Details Textuals)	Jul. 01, 2021USD ($)shares	Jun. 30, 2021USD ($)	Aug. 31, 2021USD ($)	Sep. 30, 2021USD ($)	Sep. 30, 2021USD ($)	Sep. 30, 2020USD ($)	Dec. 31, 2020USD ($)
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Long-term debt issued				$ 4,100,000,000	$ 4,100,000,000
Redemption of long-term debt			$ 2,600,000,000		3,242,000,000	$ 682,000,000
Net assets of DT Midstream				3,999,000,000
DTE Vantage
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Impairment charge					27,000,000
DTE Vantage \| Property, plant and equipment
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Impairment of long-lived assets held for use					18,000,000
DTE Vantage \| Other noncurrent assets
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Impairment of long-lived assets held for use					9,000,000
DT Midstream \| Discontinued operations, spinoff
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Total Assets of Discontinued Operations for DTE Energy				0	0		$ 8,076,000,000
Total Liabilities of Discontinued Operations for DTE Energy				0	$ 0		$ 935,000,000
Net assets of DT Midstream	$ 4,000,000,000
Maximum \| DT Midstream \| Discontinued operations, spinoff
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Transition Services Agreement period	24 months
Senior Notes
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Redemption of long-term debt				$ 2,600,000,000
DT Midstream
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Distribution of shares (in shares) \| shares	96,732,466
Share distribution ratio	0.5
Discount and debt issuance costs		$ 53,000,000
Cash payment for dividend to DTE Energy		501,000,000
DT Midstream \| June 2021 Variable Rate Term Loan maturing in 2028
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Long-term debt issued		1,000,000,000
DT Midstream \| Senior Notes
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Long-term debt issued		2,100,000,000
DT Midstream \| Affiliates
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Cash payment for short-term borrowings due to DTE Energy		2,537,000,000
Net cash payment for accounts receivable due from and accounts payable due to DTE Energy		$ 9,000,000

Dispositions and Impairments (F

Dispositions and Impairments (Financial Results That Have Been Reclassified from Continuing Operations and Included in Discontinued Operations) (Details) - USD ($)	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021
Other (Income) and Deductions
Income (Loss) from Discontinued Operations, Net of Taxes	$ (33,000,000)	$ 107,000,000	$ 112,000,000	$ 257,000,000
Less: Net Income Attributable to Noncontrolling Interests	0	3,000,000	6,000,000	8,000,000
Net Income (Loss) from Discontinued Operations	(33,000,000)	104,000,000	106,000,000	249,000,000
Transaction costs	30,000,000	0	59,000,000	0	$ 67,000,000
DT Midstream \| Discontinued operations, spinoff
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Operating Revenues — Non-utility operations	0	204,000,000	405,000,000	546,000,000
Operating Expenses
Cost of gas and other — non-utility	0	6,000,000	15,000,000	14,000,000
Operation and maintenance	30,000,000	32,000,000	124,000,000	80,000,000
Depreciation and amortization	0	38,000,000	82,000,000	110,000,000
Taxes other than income	0	3,000,000	13,000,000	12,000,000
Asset (gains) losses and impairments, net	0	(4,000,000)	17,000,000	(4,000,000)
Operating Expenses	30,000,000	75,000,000	251,000,000	212,000,000
Operating Income (Loss)	(30,000,000)	129,000,000	154,000,000	334,000,000
Other (Income) and Deductions
Interest expense	0	29,000,000	50,000,000	82,000,000
Interest income	0	(4,000,000)	(4,000,000)	(6,000,000)
Other income	0	(45,000,000)	(62,000,000)	(98,000,000)
Other (Income) and Deductions	0	(20,000,000)	(16,000,000)	(22,000,000)
Income (Loss) from Discontinued Operations Before Income Taxes	(30,000,000)	149,000,000	170,000,000	356,000,000
Income Tax Expense	3,000,000	42,000,000	58,000,000	99,000,000
Income (Loss) from Discontinued Operations, Net of Taxes	(33,000,000)	107,000,000	112,000,000	257,000,000
Less: Net Income Attributable to Noncontrolling Interests	0	3,000,000	6,000,000	8,000,000
Net Income (Loss) from Discontinued Operations	$ (33,000,000)	$ 104,000,000	$ 106,000,000	$ 249,000,000

Dispositions and Impairments (M

Dispositions and Impairments (Major Classes of Assets and Liabilities Transferred and Presented as Discontinued Operations) (Details) - USD ($)	Sep. 30, 2021	Dec. 31, 2020
Total Assets of Discontinued Operations
Current assets of discontinued operations for DTE Energy	$ 0	$ 217,000,000
Noncurrent assets of discontinued operations for DTE Energy	0	7,859,000,000
Total Liabilities of Discontinued Operations
Current liabilities of discontinued operations for DTE Energy	0	99,000,000
Noncurrent liabilities of discontinued operations for DTE Energy	0	836,000,000
Discontinued operations, spinoff \| DT Midstream
Discontinued Operations and Disposal Groups [Abstract]
Cash		42,000,000
Total Assets of Discontinued Operations
Cash		42,000,000
Accounts receivable		126,000,000
Inventories		8,000,000
Other		44,000,000
Current assets of DT Midstream		220,000,000
Less: Previously affiliated amounts eliminated at DTE Energy		3,000,000
Current assets of discontinued operations for DTE Energy		217,000,000
Investments in equity method investees		1,691,000,000
Net property, plant, and equipment		3,470,000,000
Goodwill		473,000,000
Intangible assets		2,140,000,000
Notes receivable		19,000,000
Operating lease right-of-use assets		45,000,000
Other		21,000,000
Noncurrent assets of discontinued operations for DTE Energy		7,859,000,000
Total Assets of Discontinued Operations for DTE Energy	0	8,076,000,000
Total Liabilities of Discontinued Operations
Accounts payable		39,000,000
Operating lease liabilities		17,000,000
Short-term borrowings due to DTE Energy		2,913,000,000
Other		53,000,000
Current liabilities of DT Midstream		3,022,000,000
Less: Previously affiliated amounts eliminated at DTE Energy		2,923,000,000
Current liabilities of discontinued operations for DTE Energy		99,000,000
Deferred income taxes		753,000,000
Asset retirement obligations		10,000,000
Operating lease liabilities		28,000,000
Other		45,000,000
Noncurrent liabilities of discontinued operations for DTE Energy		836,000,000
Total Liabilities of Discontinued Operations for DTE Energy	$ 0	$ 935,000,000

Dispositions and Impairments (S

Dispositions and Impairments (Significant Non-cash Items, Capital Expenditures, and Significant Financing Activities of Discontinued Operations) (Details) - DT Midstream - Discontinued operations, spinoff - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020
Operating Activities
Depreciation and amortization	$ 82	$ 110
Deferred income taxes	57	95
Equity earnings of equity method investees	(59)	(75)
Asset (gains) losses and impairments, net	19	(4)
Investing Activities
Plant and equipment expenditures — non-utility	(60)	(440)
Financing Activities
Acquisition related deferred payment, excluding accretion	$ 0	$ (380)

Revenue (Disaggregation of Reve

Revenue (Disaggregation of Revenue By Segment) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Disaggregation of Revenue [Line Items]
Revenues	$ 3,715	$ 3,080	$ 10,317	$ 8,343
Electric
Disaggregation of Revenue [Line Items]
Revenues	1,702	1,693	4,477	4,221
Electric \| Residential
Disaggregation of Revenue [Line Items]
Revenues	885	900	2,262	2,169
Electric \| Commercial
Disaggregation of Revenue [Line Items]
Revenues	533	498	1,452	1,313
Electric \| Industrial
Disaggregation of Revenue [Line Items]
Revenues	167	157	473	434
Electric \| Other
Disaggregation of Revenue [Line Items]
Revenues	117	138	290	305
Electric \| Other \| DTE Sustainable Generation
Disaggregation of Revenue [Line Items]
Revenues	2	3	9	10
Gas
Disaggregation of Revenue [Line Items]
Revenues	193	173	1,070	964
Gas \| Other
Disaggregation of Revenue [Line Items]
Revenues	44	32	114	98
Gas \| Gas sales
Disaggregation of Revenue [Line Items]
Revenues	95	92	726	655
Gas \| End User Transportation
Disaggregation of Revenue [Line Items]
Revenues	38	34	171	154
Gas \| Intermediate Transportation
Disaggregation of Revenue [Line Items]
Revenues	16	15	59	57
DTE Vantage
Disaggregation of Revenue [Line Items]
Revenues	372	324	1,132	850
Energy Trading
Disaggregation of Revenue [Line Items]
Revenues	$ 1,602	$ 1,061	$ 4,208	$ 2,714

Revenue (Revenues Outside the S

Revenue (Revenues Outside the Scope of Topic 606) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Disaggregation of Revenue [Line Items]
Leases	$ 68	$ 57	$ 132	$ 125
Electric
Disaggregation of Revenue [Line Items]
Other revenues	6	8	14	18
Gas
Disaggregation of Revenue [Line Items]
Other revenues	1	2	5	7
Alternative Revenue Program	0	0	0	2
DTE Vantage
Disaggregation of Revenue [Line Items]
Leases	26	26	70	74
Energy Trading
Disaggregation of Revenue [Line Items]
Derivatives	$ 1,324	$ 731	$ 3,377	$ 1,835

Revenue (Deferred Revenue Activ

Revenue (Deferred Revenue Activity) (Details) - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2021	Dec. 31, 2020
Contract Liability [Roll Forward]
Beginning Balance	$ 65
Increases due to cash received or receivable, excluding amounts recognized as revenue during the period	79
Revenue recognized that was included in the deferred revenue balance at the beginning of the period	(19)
Ending Balance	$ 125
Discontinued operations, spinoff \| DT Midstream
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Deferred revenue		$ 22

Revenue (Expected Recognition o

Revenue (Expected Recognition of Deferred Revenue) (Details) $ in Millions	Sep. 30, 2021USD ($)
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Remaining performance obligation	$ 125
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2021-10-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Remaining performance obligation	$ 72
Remaining performance obligation, expected timing of satisfaction	3 months
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2022-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Remaining performance obligation	$ 50
Remaining performance obligation, expected timing of satisfaction	1 year
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2023-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Remaining performance obligation	$ 1
Remaining performance obligation, expected timing of satisfaction	1 year
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2024-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Remaining performance obligation	$ 1
Remaining performance obligation, expected timing of satisfaction	1 year
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2025-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Remaining performance obligation	$ 0
Remaining performance obligation, expected timing of satisfaction	1 year
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2026-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Remaining performance obligation	$ 1
Remaining performance obligation, expected timing of satisfaction

Revenue (Expected Timing of Per

Revenue (Expected Timing of Performance Obligation Satisfaction) (Details) $ in Millions	Sep. 30, 2021USD ($)
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Remaining performance obligation	$ 125
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2021-10-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Remaining performance obligation	$ 72
Remaining performance obligation, expected timing of satisfaction	3 months
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2022-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Remaining performance obligation	$ 50
Remaining performance obligation, expected timing of satisfaction	1 year
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2023-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Remaining performance obligation	$ 1
Remaining performance obligation, expected timing of satisfaction	1 year
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2024-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Remaining performance obligation	$ 1
Remaining performance obligation, expected timing of satisfaction	1 year
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2025-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Remaining performance obligation	$ 0
Remaining performance obligation, expected timing of satisfaction	1 year
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2026-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Remaining performance obligation	$ 1
Remaining performance obligation, expected timing of satisfaction
Fixed-price Contract
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Remaining performance obligation	$ 1,273
Fixed-price Contract \| DTE Electric
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Remaining performance obligation	25
Fixed-price Contract \| Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2021-10-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Remaining performance obligation	$ 41
Remaining performance obligation, expected timing of satisfaction	3 months
Fixed-price Contract \| Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2021-10-01 \| DTE Electric
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Remaining performance obligation	$ 2
Remaining performance obligation, expected timing of satisfaction	3 months
Fixed-price Contract \| Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2022-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Remaining performance obligation	$ 308
Remaining performance obligation, expected timing of satisfaction	1 year
Fixed-price Contract \| Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2022-01-01 \| DTE Electric
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Remaining performance obligation	$ 8
Remaining performance obligation, expected timing of satisfaction	1 year
Fixed-price Contract \| Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2023-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Remaining performance obligation	$ 264
Remaining performance obligation, expected timing of satisfaction	1 year
Fixed-price Contract \| Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2023-01-01 \| DTE Electric
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Remaining performance obligation	$ 7
Remaining performance obligation, expected timing of satisfaction	1 year
Fixed-price Contract \| Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2024-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Remaining performance obligation	$ 159
Remaining performance obligation, expected timing of satisfaction	1 year
Fixed-price Contract \| Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2024-01-01 \| DTE Electric
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Remaining performance obligation	$ 7
Remaining performance obligation, expected timing of satisfaction	1 year
Fixed-price Contract \| Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2025-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Remaining performance obligation	$ 80
Remaining performance obligation, expected timing of satisfaction	1 year
Fixed-price Contract \| Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2025-01-01 \| DTE Electric
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Remaining performance obligation	$ 1
Remaining performance obligation, expected timing of satisfaction	1 year
Fixed-price Contract \| Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2026-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Remaining performance obligation	$ 421
Remaining performance obligation, expected timing of satisfaction
Fixed-price Contract \| Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2026-01-01 \| DTE Electric
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Remaining performance obligation	$ 0
Remaining performance obligation, expected timing of satisfaction

Regulatory Matters (Details Tex

Regulatory Matters (Details Textuals) - MPSC - USD ($) $ in Millions	Feb. 12, 2021	Aug. 31, 2021	Jun. 23, 2021	Mar. 26, 2021	Jul. 09, 2020
DTE Electric
Public Utilities, General Disclosures [Line Items]
Regulatory liability for non-plant-related accumulated deferred income tax balances that resulted from the TCJA, accelerated amortization approved					$ 102
Requested securitization of qualified costs				$ 184
Authorized issuance of securitization bonds of qualified costs, maximum			$ 236
DTE Electric \| Tree Trim Costs
Public Utilities, General Disclosures [Line Items]
Requested regulatory liability		$ 70
DTE Gas \| 2021 Gas Rate Case Filing
Public Utilities, General Disclosures [Line Items]
Requested rate increase	$ 195
Return on equity percent	9.90%
Return on equity requested percent	10.25%

Common Stock and Earnings Per_3

Common Stock and Earnings Per Share (Basic and Diluted Income Per Share Calculation) (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Basic Earnings per Share
Net Income attributable to DTE Energy — continuing operations	$ 58	$ 372	$ 495	$ 844
Less: Allocation of earnings to net restricted stock awards	0	1	1	2
Net income from continuing operations available to common shareholders — basic	58	371	494	842
Net Income (Loss) attributable to DTE Energy — discontinued operations	(33)	104	106	249
Net income available to common shareholders — basic	$ 25	$ 475	$ 600	$ 1,091
Average number of common shares outstanding — basic (in shares)	193	193	193	192
Continuing operations (in dollars per share)	$ 0.30	$ 1.93	$ 2.55	$ 4.37
Discontinued operations (in dollars per share)	(0.17)	0.54	0.55	1.30
Basic Earnings per Common Share (in dollars per share)	$ 0.13	$ 2.47	$ 3.10	$ 5.67
Diluted Earnings per Share
Net Income attributable to DTE Energy — continuing operations	$ 58	$ 372	$ 495	$ 844
Less: Allocation of earnings to net restricted stock awards	0	1	1	2
Net income from continuing operations available to common shareholders — diluted	58	371	494	842
Net Income (Loss) attributable to DTE Energy — discontinued operations	(33)	104	106	249
Net income available to common shareholders — diluted	$ 25	$ 475	$ 600	$ 1,091
Average number of common shares outstanding — basic (in shares)	193	193	193	192
Average dilutive equity units, performance share awards, and stock options (in shares)	1	0	1	1
Average number of common shares outstanding — diluted (in shares)	194	193	194	193
Continuing operations (in dollars per share)	$ 0.30	$ 1.92	$ 2.55	$ 4.37
Discontinued operations (in dollars per share)	(0.17)	0.54	0.55	1.29
Diluted Earnings per Common Share (in dollars per share)	$ 0.13	$ 2.46	$ 3.10	$ 5.66
Antidilutive securities excluded from computation of earnings per share (in shares)	11.1	10.3	11.5	10.3

Common Stock and Earnings Per_4

Common Stock and Earnings Per Share (Details Textuals) $ / shares in Units, shares in Millions	1 Months Ended
	Jul. 31, 2021day$ / shares	Dec. 31, 2019USD ($)$ / shares	Nov. 30, 2022shares	Sep. 30, 2021USD ($)shares
Debt Instrument [Line Items]
Face amount \| $				$ 4,100,000,000
Equity units, face amount of attached debt instrument \| $		$ 1,000
Equity units subject to mandatory redemption
Debt Instrument [Line Items]
Forward contract indexed to issuer's equity, forward rate per share (in dollars per share) \| $ / shares		$ 50
Equity units, percentage interest in attached debt instrument		0.005%
Financial instruments subject to mandatory redemption, settlement terms, share value, amount \| $		$ 150,000,000
Stock purchase contract liability \| $				$ 64,000,000
Financial instruments subject to mandatory redemption, settlement terms, maximum number of shares (in shares) \| shares				13
Equity units subject to mandatory redemption \| Minimum \| Forecast
Debt Instrument [Line Items]
Financial instruments subject to mandatory redemption, settlement terms, number of shares (in shares) \| shares			9.8
Equity units subject to mandatory redemption \| Maximum \| Forecast
Debt Instrument [Line Items]
Financial instruments subject to mandatory redemption, settlement terms, number of shares (in shares) \| shares			12.2
Equity units subject to mandatory redemption \| Equal to or greater than $133.08, 0.3757 shares of common stock
Debt Instrument [Line Items]
Number of consecutive scheduled trading days \| day	20
Financial instruments subject to mandatory redemption, anti-dilution provision, conversion ratio	0.3757
Equity units subject to mandatory redemption \| Equal to or greater than $133.08, 0.3757 shares of common stock \| Minimum
Debt Instrument [Line Items]
Financial instruments subject to mandatory redemption, anti-dilution provision, stock price threshold (in dollars per share) \| $ / shares	$ 133.08
Equity units subject to mandatory redemption \| Less than $133.08, but greater than $106.50, number of shares of common stock equal to $50 divided by the AMV
Debt Instrument [Line Items]
Financial instruments subject to mandatory redemption, anti-dilution provision, conversion ratio	50
Equity units subject to mandatory redemption \| Less than $133.08, but greater than $106.50, number of shares of common stock equal to $50 divided by the AMV \| Minimum
Debt Instrument [Line Items]
Financial instruments subject to mandatory redemption, anti-dilution provision, stock price threshold (in dollars per share) \| $ / shares	$ 106.50
Equity units subject to mandatory redemption \| Less than $133.08, but greater than $106.50, number of shares of common stock equal to $50 divided by the AMV \| Maximum
Debt Instrument [Line Items]
Financial instruments subject to mandatory redemption, anti-dilution provision, stock price threshold (in dollars per share) \| $ / shares	$ 133.08
Equity units subject to mandatory redemption \| Less than or equal to $106.50, 0.4695 shares of common stock
Debt Instrument [Line Items]
Financial instruments subject to mandatory redemption, anti-dilution provision, conversion ratio	0.4695
Equity units subject to mandatory redemption \| Less than or equal to $106.50, 0.4695 shares of common stock \| Maximum
Debt Instrument [Line Items]
Financial instruments subject to mandatory redemption, anti-dilution provision, stock price threshold (in dollars per share) \| $ / shares	$ 106.50
November 2019 Series F 2.25% RSNs Maturing 2025 \| Equity Units
Debt Instrument [Line Items]
Face amount \| $		$ 1,300,000,000
Interest rate		2.25%

Fair Value (Assets and Liabilit

Fair Value (Assets and Liabilities Recorded at Fair Value on a Recurring Basis) (Details) - USD ($) $ in Millions	Sep. 30, 2021	Dec. 31, 2020
Derivative assets
Derivative assets, gross	$ 2,340	$ 567
Derivative asset, netting	(1,912)	(411)
Derivative assets, net	428	156
Derivative liabilities
Derivative liabilities, gross	(2,557)	(533)
Derivative liability, netting	1,848	405
Derivative liabilities, net	(709)	(128)
DTE Electric
Assets
Nuclear decommissioning trusts	2,007	1,855
Current liabilities
Derivative liabilities
Derivative liabilities, gross	(2,011)	(386)
Noncurrent liabilities
Derivative liabilities
Derivative liabilities, gross	(546)	(147)
Natural gas
Derivative assets
Derivative assets, gross	778	233
Derivative asset, netting	(715)	(156)
Derivative assets, net	63	77
Derivative liabilities
Derivative liabilities, gross	(1,055)	(223)
Derivative liability, netting	664	151
Derivative liabilities, net	(391)	(72)
Electricity
Derivative assets
Derivative assets, gross	952	180
Derivative asset, netting	(627)	(120)
Derivative assets, net	325	60
Derivative liabilities
Derivative liabilities, gross	(916)	(168)
Derivative liability, netting	614	125
Derivative liabilities, net	(302)	(43)
Environmental & Other
Derivative assets
Derivative assets, gross	610	154
Derivative asset, netting	(570)	(135)
Derivative assets, net	40	19
Derivative liabilities
Derivative liabilities, gross	(581)	(137)
Derivative liability, netting	570	129
Derivative liabilities, net	(11)	(8)
Foreign currency exchange contracts
Derivative liabilities
Derivative liabilities, gross	(5)	(5)
Derivative liability, netting	0	0
Derivative liabilities, net	(5)	(5)
Cash equivalents \| DTE Electric
Assets
Nuclear decommissioning trusts	34	27
Private equity and other \| DTE Electric
Assets
Nuclear decommissioning trusts	175	104
Equity securities \| DTE Electric
Assets
Nuclear decommissioning trusts	1,140	1,169
Fixed income securities \| DTE Electric
Assets
Nuclear decommissioning trusts	658	555
Recurring
Assets
Cash equivalents	9	438
Derivative assets
Derivative asset, netting	(1,912)	(411)
Derivative assets, net	428	156
Total assets	2,598	2,609
Derivative liabilities
Derivative liability, netting	1,848	405
Derivative liabilities, net	(709)	(128)
Net Assets (Liabilities) at end of period	1,889	2,481
Net Assets at end of period, netting	(64)	(6)
Recurring \| DTE Electric
Assets
Cash equivalents	0	4
Derivative assets
Total assets	2,048	1,890
Recurring \| Current assets
Derivative assets
Derivative asset, netting	(1,591)	(330)
Total assets	356	554
Recurring \| Current assets \| DTE Electric
Derivative assets
Total assets	12	8
Recurring \| Noncurrent assets
Derivative assets
Derivative asset, netting	(321)	(81)
Total assets	2,242	2,055
Recurring \| Noncurrent assets \| DTE Electric
Derivative assets
Total assets	2,036	1,882
Recurring \| Current liabilities
Derivative liabilities
Derivative liability, netting	1,546	318
Derivative liabilities, net	(465)	(68)
Recurring \| Noncurrent liabilities
Derivative liabilities
Derivative liability, netting	302	87
Derivative liabilities, net	(244)	(60)
Recurring \| Restricted cash
Assets
Cash equivalents	1	2
Recurring \| Natural gas
Derivative assets
Derivative asset, netting	(715)	(156)
Derivative assets, net	63	77
Derivative liabilities
Derivative liability, netting	664	151
Derivative liabilities, net	(391)	(72)
Recurring \| Electricity
Derivative assets
Derivative asset, netting	(627)	(120)
Derivative assets, net	325	60
Derivative liabilities
Derivative liability, netting	614	125
Derivative liabilities, net	(302)	(43)
Recurring \| Environmental & Other
Derivative assets
Derivative asset, netting	(570)	(135)
Derivative assets, net	40	19
Derivative liabilities
Derivative liability, netting	570	129
Derivative liabilities, net	(11)	(8)
Recurring \| Foreign currency exchange contracts
Derivative liabilities
Derivative liability, netting	0	0
Derivative liabilities, net	(5)	(5)
Recurring \| Derivative assets — FTRs \| DTE Electric
Derivative assets
Derivative assets, net	12	4
Recurring \| Cash equivalents
Assets
Nuclear decommissioning trusts	34	27
Other investments	86	97
Recurring \| Cash equivalents \| DTE Electric
Assets
Nuclear decommissioning trusts	34	27
Other investments	11	11
Recurring \| Private equity and other
Assets
Nuclear decommissioning trusts	175	104
Recurring \| Private equity and other \| DTE Electric
Assets
Nuclear decommissioning trusts	175	104
Recurring \| Equity securities
Assets
Nuclear decommissioning trusts	1,140	1,169
Other investments	61	55
Recurring \| Equity securities \| DTE Electric
Assets
Nuclear decommissioning trusts	1,140	1,169
Other investments	18	16
Recurring \| Fixed income securities
Assets
Nuclear decommissioning trusts	658	555
Other investments	7	8
Recurring \| Fixed income securities \| DTE Electric
Assets
Nuclear decommissioning trusts	658	555
Recurring \| Level 1
Assets
Cash equivalents	9	438
Derivative assets
Derivative assets, gross	579	99
Total assets	1,847	1,773
Derivative liabilities
Derivative liabilities, gross	(425)	(88)
Net Assets (Liabilities) at end of period	1,422	1,685
Recurring \| Level 1 \| DTE Electric
Assets
Cash equivalents	0	4
Derivative assets
Total assets	1,134	1,107
Recurring \| Level 1 \| Current assets
Derivative assets
Total assets	506	532
Recurring \| Level 1 \| Current assets \| DTE Electric
Derivative assets
Total assets	0	4
Recurring \| Level 1 \| Noncurrent assets
Derivative assets
Total assets	1,341	1,241
Recurring \| Level 1 \| Noncurrent assets \| DTE Electric
Derivative assets
Total assets	1,134	1,103
Recurring \| Level 1 \| Current liabilities
Derivative liabilities
Derivative liabilities, gross	(409)	(84)
Recurring \| Level 1 \| Noncurrent liabilities
Derivative liabilities
Derivative liabilities, gross	(16)	(4)
Recurring \| Level 1 \| Natural gas
Derivative assets
Derivative assets, gross	579	99
Derivative liabilities
Derivative liabilities, gross	(425)	(88)
Recurring \| Level 1 \| Electricity
Derivative assets
Derivative assets, gross	0	0
Derivative liabilities
Derivative liabilities, gross	0	0
Recurring \| Level 1 \| Environmental & Other
Derivative assets
Derivative assets, gross	0	0
Derivative liabilities
Derivative liabilities, gross	0	0
Recurring \| Level 1 \| Foreign currency exchange contracts
Derivative liabilities
Derivative liabilities, gross	0	0
Recurring \| Level 1 \| Derivative assets — FTRs \| DTE Electric
Derivative assets
Derivative assets, net	0	0
Recurring \| Level 1 \| Cash equivalents
Assets
Nuclear decommissioning trusts	34	27
Other investments	86	97
Recurring \| Level 1 \| Cash equivalents \| DTE Electric
Assets
Nuclear decommissioning trusts	34	27
Other investments	11	11
Recurring \| Level 1 \| Private equity and other
Assets
Nuclear decommissioning trusts	0	0
Recurring \| Level 1 \| Private equity and other \| DTE Electric
Assets
Nuclear decommissioning trusts	0	0
Recurring \| Level 1 \| Equity securities
Assets
Nuclear decommissioning trusts	944	947
Other investments	61	55
Recurring \| Level 1 \| Equity securities \| DTE Electric
Assets
Nuclear decommissioning trusts	944	947
Other investments	18	16
Recurring \| Level 1 \| Fixed income securities
Assets
Nuclear decommissioning trusts	127	102
Other investments	7	8
Recurring \| Level 1 \| Fixed income securities \| DTE Electric
Assets
Nuclear decommissioning trusts	127	102
Recurring \| Level 2
Assets
Cash equivalents	0	0
Derivative assets
Derivative assets, gross	1,451	352
Total assets	1,880	723
Derivative liabilities
Derivative liabilities, gross	(1,459)	(327)
Net Assets (Liabilities) at end of period	421	396
Recurring \| Level 2 \| DTE Electric
Assets
Cash equivalents	0	0
Derivative assets
Total assets	429	371
Recurring \| Level 2 \| Current assets
Derivative assets
Total assets	1,183	260
Recurring \| Level 2 \| Current assets \| DTE Electric
Derivative assets
Total assets	0	0
Recurring \| Level 2 \| Noncurrent assets
Derivative assets
Total assets	697	463
Recurring \| Level 2 \| Noncurrent assets \| DTE Electric
Derivative assets
Total assets	429	371
Recurring \| Level 2 \| Current liabilities
Derivative liabilities
Derivative liabilities, gross	(1,138)	(223)
Recurring \| Level 2 \| Noncurrent liabilities
Derivative liabilities
Derivative liabilities, gross	(321)	(104)
Recurring \| Level 2 \| Natural gas
Derivative assets
Derivative assets, gross	146	74
Derivative liabilities
Derivative liabilities, gross	(297)	(59)
Recurring \| Level 2 \| Electricity
Derivative assets
Derivative assets, gross	707	128
Derivative liabilities
Derivative liabilities, gross	(576)	(126)
Recurring \| Level 2 \| Environmental & Other
Derivative assets
Derivative assets, gross	598	150
Derivative liabilities
Derivative liabilities, gross	(581)	(137)
Recurring \| Level 2 \| Foreign currency exchange contracts
Derivative liabilities
Derivative liabilities, gross	(5)	(5)
Recurring \| Level 2 \| Derivative assets — FTRs \| DTE Electric
Derivative assets
Derivative assets, net	0	0
Recurring \| Level 2 \| Cash equivalents
Assets
Nuclear decommissioning trusts	0	0
Other investments	0	0
Recurring \| Level 2 \| Cash equivalents \| DTE Electric
Assets
Nuclear decommissioning trusts	0	0
Other investments	0	0
Recurring \| Level 2 \| Private equity and other
Assets
Nuclear decommissioning trusts	0	0
Recurring \| Level 2 \| Private equity and other \| DTE Electric
Assets
Nuclear decommissioning trusts	0	0
Recurring \| Level 2 \| Equity securities
Assets
Nuclear decommissioning trusts	0	0
Other investments	0	0
Recurring \| Level 2 \| Equity securities \| DTE Electric
Assets
Nuclear decommissioning trusts	0	0
Other investments	0	0
Recurring \| Level 2 \| Fixed income securities
Assets
Nuclear decommissioning trusts	429	371
Other investments	0	0
Recurring \| Level 2 \| Fixed income securities \| DTE Electric
Assets
Nuclear decommissioning trusts	429	371
Recurring \| Level 3
Assets
Cash equivalents	0	0
Derivative assets
Derivative assets, gross	310	116
Total assets	310	116
Derivative liabilities
Derivative liabilities, gross	(673)	(118)
Net Assets (Liabilities) at end of period	(363)	(2)
Recurring \| Level 3 \| DTE Electric
Assets
Cash equivalents	0	0
Derivative assets
Total assets	12	4
Recurring \| Level 3 \| Current assets
Derivative assets
Total assets	258	92
Recurring \| Level 3 \| Current assets \| DTE Electric
Derivative assets
Total assets	12	4
Recurring \| Level 3 \| Noncurrent assets
Derivative assets
Total assets	52	24
Recurring \| Level 3 \| Noncurrent assets \| DTE Electric
Derivative assets
Total assets	0	0
Recurring \| Level 3 \| Current liabilities
Derivative liabilities
Derivative liabilities, gross	(464)	(79)
Recurring \| Level 3 \| Noncurrent liabilities
Derivative liabilities
Derivative liabilities, gross	(209)	(39)
Recurring \| Level 3 \| Natural gas
Derivative assets
Derivative assets, gross	53	60
Derivative liabilities
Derivative liabilities, gross	(333)	(76)
Recurring \| Level 3 \| Electricity
Derivative assets
Derivative assets, gross	245	52
Derivative liabilities
Derivative liabilities, gross	(340)	(42)
Recurring \| Level 3 \| Environmental & Other
Derivative assets
Derivative assets, gross	12	4
Derivative liabilities
Derivative liabilities, gross	0	0
Recurring \| Level 3 \| Foreign currency exchange contracts
Derivative liabilities
Derivative liabilities, gross	0
Recurring \| Level 3 \| Derivative assets — FTRs \| DTE Electric
Derivative assets
Derivative assets, net	12	4
Recurring \| Level 3 \| Cash equivalents
Assets
Nuclear decommissioning trusts	0	0
Other investments	0	0
Recurring \| Level 3 \| Cash equivalents \| DTE Electric
Assets
Nuclear decommissioning trusts	0	0
Other investments	0	0
Recurring \| Level 3 \| Private equity and other
Assets
Nuclear decommissioning trusts	0	0
Recurring \| Level 3 \| Private equity and other \| DTE Electric
Assets
Nuclear decommissioning trusts	0	0
Recurring \| Level 3 \| Equity securities
Assets
Nuclear decommissioning trusts	0	0
Other investments	0	0
Recurring \| Level 3 \| Equity securities \| DTE Electric
Assets
Nuclear decommissioning trusts	0	0
Other investments	0	0
Recurring \| Level 3 \| Fixed income securities
Assets
Nuclear decommissioning trusts	0	0
Other investments	0	0
Recurring \| Level 3 \| Fixed income securities \| DTE Electric
Assets
Nuclear decommissioning trusts	0	0
Recurring \| Other
Derivative assets
Total assets	473	408
Derivative liabilities
Net Assets (Liabilities) at end of period	473	408
Recurring \| Other \| DTE Electric
Derivative assets
Total assets	473	408
Recurring \| Other \| Noncurrent assets
Derivative assets
Total assets	473	408
Recurring \| Other \| Noncurrent assets \| DTE Electric
Derivative assets
Total assets	473	408
Recurring \| Other \| Private equity and other
Assets
Nuclear decommissioning trusts	175	104
Recurring \| Other \| Private equity and other \| DTE Electric
Assets
Nuclear decommissioning trusts	175	104
Recurring \| Other \| Equity securities
Assets
Nuclear decommissioning trusts	196	222
Recurring \| Other \| Equity securities \| DTE Electric
Assets
Nuclear decommissioning trusts	196	222
Recurring \| Other \| Fixed income securities
Assets
Nuclear decommissioning trusts	102	82
Recurring \| Other \| Fixed income securities \| DTE Electric
Assets
Nuclear decommissioning trusts	$ 102	$ 82

Fair Value (Details Textuals)

Fair Value (Details Textuals) - USD ($) $ in Millions	9 Months Ended
Fair Value (Details Textuals) - USD ($) $ in Millions	Sep. 30, 2021	Dec. 31, 2020
Nuclear decommissioning trust fund \| Fixed income securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities with no contractual maturity date	$ 102
Equity or debt securities \| Minimum
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments, redemption notice period	7 days
Equity or debt securities \| Maximum
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments, redemption notice period	65 days
Private equity and other
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Unfunded commitments related to investments classified as NAV assets	$ 155	$ 183
Private equity and other \| Minimum
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments classified as NAV assets, general contractual durations	7 years
Private equity and other \| Maximum
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments classified as NAV assets, general contractual durations	12 years

Fair Value (Reconciliation of L

Fair Value (Reconciliation of Level 3 Assets and Liabilities at Fair Value on a Recurring Basis) (Details) - Recurring - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Roll Forward]
Net Assets (Liabilities) as of beginning of period	$ (215)	$ 46	$ (2)	$ 4
Transfers from Level 3 into Level 2	0	(1)	0	(5)
Total gains (losses)
Included in earnings	(183)	(42)	(361)	39
Recorded in Regulatory liabilities	(1)	9	14	21
Purchases, issuances, and settlements
Settlements	36	(39)	(14)	(86)
Net Assets (Liabilities) as of end of period	(363)	(27)	(363)	(27)
Total gains (losses) included in Net Income attributed to the change in unrealized gains (losses) related to assets and liabilities held at end of period	(141)	(47)	(372)	16
Total gains (losses) included in Regulatory liabilities attributed to the change in unrealized gains (losses) related to assets and liabilities held at end of period			12	7
DTE Electric
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Roll Forward]
Net Assets (Liabilities) as of beginning of period	15	10	4	3
Total gains (losses)
Recorded in Regulatory liabilities	(1)	9	14	21
Purchases, issuances, and settlements
Settlements	(2)	(12)	(6)	(17)
Net Assets (Liabilities) as of end of period	12	7	12	7
Total gains (losses) included in Regulatory liabilities attributed to the change in unrealized gains (losses) related to assets and liabilities held at end of period	0	0	12	7
Natural gas
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Roll Forward]
Net Assets (Liabilities) as of beginning of period	(181)	20	(16)	(15)
Transfers from Level 3 into Level 2	0	(1)	0	(5)
Total gains (losses)
Included in earnings	(162)	(80)	(356)	(44)
Recorded in Regulatory liabilities	0	0	0	0
Purchases, issuances, and settlements
Settlements	63	22	92	25
Net Assets (Liabilities) as of end of period	(280)	(39)	(280)	(39)
Total gains (losses) included in Net Income attributed to the change in unrealized gains (losses) related to assets and liabilities held at end of period	(109)	(57)	(301)	(20)
Total gains (losses) included in Regulatory liabilities attributed to the change in unrealized gains (losses) related to assets and liabilities held at end of period			0	0
Electricity
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Roll Forward]
Net Assets (Liabilities) as of beginning of period	(49)	16	10	16
Transfers from Level 3 into Level 2	0	0	0	0
Total gains (losses)
Included in earnings	(21)	37	(5)	90
Recorded in Regulatory liabilities	0	0	0	0
Purchases, issuances, and settlements
Settlements	(25)	(48)	(100)	(101)
Net Assets (Liabilities) as of end of period	(95)	5	(95)	5
Total gains (losses) included in Net Income attributed to the change in unrealized gains (losses) related to assets and liabilities held at end of period	(30)	11	(54)	53
Total gains (losses) included in Regulatory liabilities attributed to the change in unrealized gains (losses) related to assets and liabilities held at end of period			0	0
Other
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Roll Forward]
Net Assets (Liabilities) as of beginning of period	15	10	4	3
Transfers from Level 3 into Level 2	0	0	0	0
Total gains (losses)
Included in earnings	0	1	0	(7)
Recorded in Regulatory liabilities	(1)	9	14	21
Purchases, issuances, and settlements
Settlements	(2)	(13)	(6)	(10)
Net Assets (Liabilities) as of end of period	12	7	12	7
Total gains (losses) included in Net Income attributed to the change in unrealized gains (losses) related to assets and liabilities held at end of period	$ (2)	$ (1)	(17)	(17)
Total gains (losses) included in Regulatory liabilities attributed to the change in unrealized gains (losses) related to assets and liabilities held at end of period			$ 12	$ 7

Fair Value (Unobservable Inputs

Fair Value (Unobservable Inputs related to Level 3 Assets and Liabilities) (Details) $ in Millions	Sep. 30, 2021USD ($)MMBTUMWh	Dec. 31, 2020USD ($)MMBTUMWh
Unobservable Inputs Valuation Techniques [Line Items]
Derivative Assets	$ 2,340	$ 567
Derivative Liabilities	(2,557)	(533)
Natural gas
Unobservable Inputs Valuation Techniques [Line Items]
Derivative Assets	778	233
Derivative Liabilities	(1,055)	(223)
Electricity
Unobservable Inputs Valuation Techniques [Line Items]
Derivative Assets	952	180
Derivative Liabilities	$ (916)	$ (168)
Level 3 \| Natural gas \| Forward basis price \| Minimum \| Discounted Cash Flow
Unobservable Inputs Valuation Techniques [Line Items]
Forward basis price \| MMBTU	(1.33)	(0.86)
Level 3 \| Natural gas \| Forward basis price \| Maximum \| Discounted Cash Flow
Unobservable Inputs Valuation Techniques [Line Items]
Forward basis price \| MMBTU	3.53	2.50
Level 3 \| Natural gas \| Forward basis price \| Weighted Average \| Discounted Cash Flow
Unobservable Inputs Valuation Techniques [Line Items]
Forward basis price \| MMBTU	(0.04)	(0.07)
Level 3 \| Electricity \| Forward basis price \| Minimum \| Discounted Cash Flow
Unobservable Inputs Valuation Techniques [Line Items]
Forward basis price \| MWh	(8)	(9)
Level 3 \| Electricity \| Forward basis price \| Maximum \| Discounted Cash Flow
Unobservable Inputs Valuation Techniques [Line Items]
Forward basis price \| MWh	10	6
Level 3 \| Electricity \| Forward basis price \| Weighted Average \| Discounted Cash Flow
Unobservable Inputs Valuation Techniques [Line Items]
Forward basis price \| MWh	(1)	0
Recurring \| Level 3
Unobservable Inputs Valuation Techniques [Line Items]
Derivative Assets	$ 310	$ 116
Derivative Liabilities	(673)	(118)
Recurring \| Level 3 \| Natural gas
Unobservable Inputs Valuation Techniques [Line Items]
Derivative Assets	53	60
Derivative Liabilities	(333)	(76)
Recurring \| Level 3 \| Electricity
Unobservable Inputs Valuation Techniques [Line Items]
Derivative Assets	245	52
Derivative Liabilities	$ (340)	$ (42)

Fair Value (Fair Value of Finan

Fair Value (Fair Value of Financial Instruments) (Details) - USD ($) $ in Millions	Sep. 30, 2021	Dec. 31, 2020
Carrying amount
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Notes receivable	$ 142	$ 141
Short-term borrowings	361	38
Notes payable	5	19
Long-term debt	17,222	19,439
Carrying amount \| DTE Electric
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Notes receivable	17	16
Short-term borrowings	159	0
Notes payable	4	17
Long-term debt	8,906	8,236
Carrying amount \| DTE Electric \| Affiliates
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Short-term borrowings	32	101
Fair value \| Level 1
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Notes receivable	0	0
Short-term borrowings	0	0
Notes payable	0	0
Long-term debt	2,241	2,547
Fair value \| Level 1 \| DTE Electric
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Notes receivable	0	0
Short-term borrowings	0	0
Notes payable	0	0
Long-term debt	0	0
Fair value \| Level 1 \| DTE Electric \| Affiliates
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Short-term borrowings	0	0
Fair value \| Level 2
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Notes receivable	0	0
Short-term borrowings	361	38
Notes payable	0	0
Long-term debt	15,486	18,230
Fair value \| Level 2 \| DTE Electric
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Notes receivable	0	0
Short-term borrowings	159	0
Notes payable	0	0
Long-term debt	9,952	9,579
Fair value \| Level 2 \| DTE Electric \| Affiliates
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Short-term borrowings	0	0
Fair value \| Level 3
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Notes receivable	142	141
Short-term borrowings	0	0
Notes payable	5	19
Long-term debt	1,104	1,397
Fair value \| Level 3 \| DTE Electric
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Notes receivable	17	16
Short-term borrowings	0	0
Notes payable	4	17
Long-term debt	150	379
Fair value \| Level 3 \| DTE Electric \| Affiliates
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Short-term borrowings	$ 32	$ 101

Fair Value (Fair Value of Nucle

Fair Value (Fair Value of Nuclear Decommissioning Trust Fund Assets) (Details) - USD ($) $ in Millions	Sep. 30, 2021	Dec. 31, 2020
Debt Securities, Available-for-sale [Line Items]
Nuclear decommissioning trust funds	$ 2,007	$ 1,855
DTE Electric
Debt Securities, Available-for-sale [Line Items]
Nuclear decommissioning trust funds	2,007	1,855
DTE Electric \| Nuclear decommissioning trust fund
Debt Securities, Available-for-sale [Line Items]
Nuclear decommissioning trust funds	2,007	1,855
DTE Electric \| Nuclear decommissioning trust fund \| Fermi 2
Debt Securities, Available-for-sale [Line Items]
Nuclear decommissioning trust funds	1,989	1,841
DTE Electric \| Nuclear decommissioning trust fund \| Fermi 1
Debt Securities, Available-for-sale [Line Items]
Nuclear decommissioning trust funds	3	3
DTE Electric \| Nuclear decommissioning trust fund \| Low-level radioactive waste
Debt Securities, Available-for-sale [Line Items]
Nuclear decommissioning trust funds	$ 15	$ 11

Fair Value (Gains and Losses an

Fair Value (Gains and Losses and Proceeds from the Sale of Securities by the Nuclear Decommissioning Trust Funds) (Details) - DTE Electric - Nuclear decommissioning trust fund - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Debt Securities, Available-for-sale [Line Items]
Realized gains	$ 21	$ 38	$ 80	$ 172
Realized losses	(1)	(11)	(9)	(103)
Proceeds from sale of securities	$ 217	$ 816	$ 854	$ 2,054

Fair Value (Fair Value and Unre

Fair Value (Fair Value and Unrealized Gains and Losses for the Nuclear Decommissioning Trust Funds) (Details) - DTE Electric - USD ($) $ in Millions	Sep. 30, 2021	Dec. 31, 2020
Debt Securities, Available-for-sale [Line Items]
Fair Value	$ 2,007	$ 1,855
Unrealized Gains	572	501
Unrealized Losses	(15)	(7)
Cash equivalents
Debt Securities, Available-for-sale [Line Items]
Fair Value	34	27
Private equity and other
Debt Securities, Available-for-sale [Line Items]
Fair Value	175	104
Unrealized Gains	41	0
Unrealized Losses	(2)	0
Equity securities
Debt Securities, Available-for-sale [Line Items]
Fair Value	1,140	1,169
Unrealized Gains	507	481
Unrealized Losses	(8)	(6)
Fixed income securities
Debt Securities, Available-for-sale [Line Items]
Fair Value	658	555
Unrealized Gains	24	20
Unrealized Losses	$ (5)	$ (1)

Fair Value (Fair Value of Fixed

Fair Value (Fair Value of Fixed Income Securities Held in Nuclear Decommissioning Trust Funds (Details) - Fixed income securities - Nuclear decommissioning trust fund $ in Millions	Sep. 30, 2021USD ($)
Debt Securities, Available-for-sale [Line Items]
Due within one year	$ 11
Due after one through five years	138
Due after five through ten years	112
Due after ten years	295
Fixed income securities total	$ 556

Fair Value (Gains (Losses) Rela

Fair Value (Gains (Losses) Related to the Trust) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Rabbi Trust
Schedule of Investments [Line Items]
Gains (losses) related to the trust	$ (1)	$ 2	$ 3	$ (7)
Equity securities
Schedule of Investments [Line Items]
Gains (losses) related to the trust	(1)	2	3	(4)
Fixed income securities
Schedule of Investments [Line Items]
Gains (losses) related to the trust	$ 0	$ 0	$ 0	$ (3)

Financial and Other Derivativ_3

Financial and Other Derivative Instruments (Fair Value of Derivative Instruments) (Details) - USD ($) $ in Millions	Sep. 30, 2021	Dec. 31, 2020
Derivatives, Fair Value [Line Items]
Derivative Assets	$ 2,340	$ 567
Derivative Liabilities	(2,557)	(533)
Current derivative assets
Derivatives, Fair Value [Line Items]
Derivative Assets	1,938	446
Current derivative liabilities
Derivatives, Fair Value [Line Items]
Derivative Liabilities	(2,011)	(386)
Noncurrent derivative assets
Derivatives, Fair Value [Line Items]
Derivative Assets	402	121
Noncurrent derivative liabilities
Derivatives, Fair Value [Line Items]
Derivative Liabilities	(546)	(147)
Foreign currency exchange contracts
Derivatives, Fair Value [Line Items]
Derivative Liabilities	(5)	(5)
Natural gas
Derivatives, Fair Value [Line Items]
Derivative Assets	778	233
Derivative Liabilities	(1,055)	(223)
Electricity
Derivatives, Fair Value [Line Items]
Derivative Assets	952	180
Derivative Liabilities	(916)	(168)
Environmental & Other
Derivatives, Fair Value [Line Items]
Derivative Assets	610	154
Derivative Liabilities	(581)	(137)
Derivatives designated as hedging instruments \| Foreign currency exchange contracts
Derivatives, Fair Value [Line Items]
Derivative Assets	0	0
Derivative Liabilities	(3)	(4)
Derivatives not designated as hedging instruments
Derivatives, Fair Value [Line Items]
Derivative Assets	2,340	567
Derivative Liabilities	(2,554)	(529)
Derivatives not designated as hedging instruments \| DTE Electric
Derivatives, Fair Value [Line Items]
Derivative Assets	12	4
Derivatives not designated as hedging instruments \| Foreign currency exchange contracts
Derivatives, Fair Value [Line Items]
Derivative Assets	0	0
Derivative Liabilities	(2)	(1)
Derivatives not designated as hedging instruments \| Natural gas
Derivatives, Fair Value [Line Items]
Derivative Assets	778	233
Derivative Liabilities	(1,055)	(223)
Derivatives not designated as hedging instruments \| Electricity
Derivatives, Fair Value [Line Items]
Derivative Assets	952	180
Derivative Liabilities	(916)	(168)
Derivatives not designated as hedging instruments \| Environmental & Other
Derivatives, Fair Value [Line Items]
Derivative Assets	610	154
Derivative Liabilities	(581)	(137)
Derivatives not designated as hedging instruments \| FTRs — Other current assets \| DTE Electric
Derivatives, Fair Value [Line Items]
Derivative Assets	$ 12	$ 4

Financial and Other Derivativ_4

Financial and Other Derivative Instruments (Details Textuals) - USD ($) $ in Millions	Sep. 30, 2021	Dec. 31, 2020
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Letters of credit that could be used to offset net derivative liabilities	$ 20	$ 7
Letters of credit received that could be used to offset net derivative assets	55	$ 9
Contractual obligation to post collateral in event of downgrade to below investment grade	575
Derivative net liability position aggregate fair value	2,180
Collateral already posted fair value	52
Derivative net asset position, fair value	1,788
Remaining amount of offsets to derivative net liability positions for hard and soft trigger provisions	$ 340

Financial and Other Derivativ_5

Financial and Other Derivative Instruments (Net Cash Collateral Offsetting Arrangements) (Details) - USD ($) $ in Millions	Sep. 30, 2021	Dec. 31, 2020
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Cash collateral netted against Derivative assets	$ (122)	$ (12)
Cash collateral netted against Derivative liabilities	58	6
Cash collateral recorded in Accounts receivable	66	14
Cash collateral recorded in Accounts payable	(8)	(1)
Total net cash collateral posted (received)	$ (6)	$ 7

Financial and Other Derivativ_6

Financial and Other Derivative Instruments (Netting Offsets of Derivative Assets and Liabilities) (Details) - USD ($) $ in Millions	Sep. 30, 2021	Dec. 31, 2020
Derivative assets
Gross Amounts of Recognized Assets (Liabilities)	$ 2,340	$ 567
Gross Amounts Offset in the Consolidated Statements of Financial Position	(1,912)	(411)
Derivative assets, net	428	156
Derivative liabilities
Gross Amounts of Recognized Assets (Liabilities)	(2,557)	(533)
Gross Amounts Offset in the Consolidated Statements of Financial Position	1,848	405
Derivative liabilities, net	(709)	(128)
Natural gas
Derivative assets
Gross Amounts of Recognized Assets (Liabilities)	778	233
Gross Amounts Offset in the Consolidated Statements of Financial Position	(715)	(156)
Derivative assets, net	63	77
Derivative liabilities
Gross Amounts of Recognized Assets (Liabilities)	(1,055)	(223)
Gross Amounts Offset in the Consolidated Statements of Financial Position	664	151
Derivative liabilities, net	(391)	(72)
Electricity
Derivative assets
Gross Amounts of Recognized Assets (Liabilities)	952	180
Gross Amounts Offset in the Consolidated Statements of Financial Position	(627)	(120)
Derivative assets, net	325	60
Derivative liabilities
Gross Amounts of Recognized Assets (Liabilities)	(916)	(168)
Gross Amounts Offset in the Consolidated Statements of Financial Position	614	125
Derivative liabilities, net	(302)	(43)
Environmental & Other
Derivative assets
Gross Amounts of Recognized Assets (Liabilities)	610	154
Gross Amounts Offset in the Consolidated Statements of Financial Position	(570)	(135)
Derivative assets, net	40	19
Derivative liabilities
Gross Amounts of Recognized Assets (Liabilities)	(581)	(137)
Gross Amounts Offset in the Consolidated Statements of Financial Position	570	129
Derivative liabilities, net	(11)	(8)
Foreign currency exchange contracts
Derivative liabilities
Gross Amounts of Recognized Assets (Liabilities)	(5)	(5)
Gross Amounts Offset in the Consolidated Statements of Financial Position	0	0
Derivative liabilities, net	$ (5)	$ (5)

Financial and Other Derivativ_7

Financial and Other Derivative Instruments (Netting Offsets Reconciliation to Balance Sheet) (Details) - USD ($) $ in Millions	Sep. 30, 2021	Dec. 31, 2020
Derivative Assets
Derivative Assets	$ 2,340	$ 567
Collateral adjustment	(122)	(12)
Derivative assets, current	347	116
Derivative assets, noncurrent	81	40
Derivative Liabilities
Derivative Liabilities	(2,557)	(533)
Collateral adjustment	58	6
Derivative liabilities, current	(465)	(68)
Derivative liabilities, noncurrent	(244)	(60)
Current derivative assets
Derivative Assets
Derivative Assets	1,938	446
Counterparty netting	(1,498)	(318)
Collateral adjustment	(93)	(12)
Derivative assets, current	347	116
Noncurrent derivative assets
Derivative Assets
Derivative Assets	402	121
Counterparty netting	(292)	(81)
Collateral adjustment	(29)	0
Derivative assets, noncurrent	81	40
Current derivative liabilities
Derivative Liabilities
Derivative Liabilities	(2,011)	(386)
Counterparty netting	1,498	318
Collateral adjustment	48	0
Derivative liabilities, current	(465)	(68)
Noncurrent derivative liabilities
Derivative Liabilities
Derivative Liabilities	(546)	(147)
Counterparty netting	292	81
Collateral adjustment	10	6
Derivative liabilities, noncurrent	$ (244)	$ (60)

Financial and Other Derivativ_8

Financial and Other Derivative Instruments (Effect of Derivatives not Designated as Hedging Instruments on the Consolidated Statement of Operations) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Derivative Instruments, Gain (Loss) [Line Items]
Gain (Loss) Recognized in Income on Derivatives	$ (78)	$ (45)	$ (281)	$ 0
Natural gas \| Operating Revenues — Non-utility operations
Derivative Instruments, Gain (Loss) [Line Items]
Gain (Loss) Recognized in Income on Derivatives	(214)	(27)	(371)	(63)
Natural gas \| Fuel, purchased power, gas, and other — non-utility
Derivative Instruments, Gain (Loss) [Line Items]
Gain (Loss) Recognized in Income on Derivatives	63	(51)	(16)	28
Electricity \| Operating Revenues — Non-utility operations
Derivative Instruments, Gain (Loss) [Line Items]
Gain (Loss) Recognized in Income on Derivatives	68	33	143	75
Environmental & Other \| Operating Revenues — Non-utility operations
Derivative Instruments, Gain (Loss) [Line Items]
Gain (Loss) Recognized in Income on Derivatives	3	2	(36)	(40)
Foreign currency exchange contracts \| Operating Revenues — Non-utility operations
Derivative Instruments, Gain (Loss) [Line Items]
Gain (Loss) Recognized in Income on Derivatives	$ 2	$ (2)	$ (1)	$ 0

Financial and Other Derivativ_9

Financial and Other Derivative Instruments (Cumulative Gross Volume of Derivative Contracts Outstanding) (Details)	9 Months Ended
	Sep. 30, 2021CAD ($)MMBTUMWhT
Natural gas (MMBtu)
Derivative [Line Items]
Commodity, energy measures \| MMBTU	2,096,409,912
Electricity (MWh)
Derivative [Line Items]
Commodity, energy measures	29,383,562
Foreign currency exchange ($ CAD)
Derivative [Line Items]
Commodity, monetary measure \| $	$ 119,281,865
Renewable Energy Certificates (MWh)
Derivative [Line Items]
Commodity, energy measures	8,387,594
Carbon emissions (Metric Tons)
Derivative [Line Items]
Commodity, mass measure \| T	48,343,793

Long-Term Debt (Schedule of Iss

Long-Term Debt (Schedule of Issued Debt) (Details) - USD ($)	Sep. 30, 2021	Jun. 30, 2021	Mar. 31, 2021
Debt Instrument [Line Items]
Amount	$ 4,100,000,000
DTE Electric \| Mortgage Bonds \| March 2021 1.9% Mortgage Bonds maturing in 2028
Debt Instrument [Line Items]
Interest rate			1.90%
Amount			$ 575,000,000
DTE Electric \| Mortgage Bonds \| March 2021 3.25% Mortgage Bonds maturing In 2051
Debt Instrument [Line Items]
Interest rate			3.25%
Amount			$ 425,000,000
DT Midstream \| June 2021 Variable Rate Term Loan maturing in 2028
Debt Instrument [Line Items]
Amount		$ 1,000,000,000
DT Midstream \| Senior Notes
Debt Instrument [Line Items]
Amount		$ 2,100,000,000
DT Midstream \| Senior Notes \| June 2021 4.125% Senior Notes maturing in 2029
Debt Instrument [Line Items]
Interest rate		4.125%
Amount		$ 1,100,000,000
DT Midstream \| Senior Notes \| June 2021 4.375% Senior Notes maturing in 2031
Debt Instrument [Line Items]
Interest rate		4.375%
Amount		$ 1,000,000,000

Long-Term Debt (Details Textual

Long-Term Debt (Details Textuals) - USD ($)	2 Months Ended	3 Months Ended	9 Months Ended
Long-Term Debt (Details Textuals) - USD ($)	Aug. 31, 2021	Sep. 30, 2021	Sep. 30, 2021	Sep. 30, 2020	Nov. 30, 2021	Jun. 30, 2021
Debt Instrument [Line Items]
Face amount		$ 4,100,000,000	$ 4,100,000,000
Redemption of long-term debt	$ 2,600,000,000		3,242,000,000	$ 682,000,000
Prepayment costs for extinguishment of long-term debt			361,000,000	0
Senior Notes
Debt Instrument [Line Items]
Redemption of long-term debt		2,600,000,000
Prepayment costs for extinguishment of long-term debt		361,000,000
Write off of unamortized issuance costs and discounts		15,000,000
2.07% First Mortgage Bonds maturing in 2031 \| Mortgage Bonds \| Forecast
Debt Instrument [Line Items]
Face amount					$ 60,000,000
Interest rate					2.07%
2.85% First Mortgage Bonds maturing in 2051 \| Mortgage Bonds \| Forecast
Debt Instrument [Line Items]
Face amount					$ 95,000,000
Interest rate					2.85%
DTE Electric
Debt Instrument [Line Items]
Redemption of long-term debt			321,000,000	$ 632,000,000
DTE Electric \| 1.45% Revenue Bonds maturing in 2030 \| Tax Exempt Revenue Bonds
Debt Instrument [Line Items]
Face amount		$ 82,000,000	$ 82,000,000
Interest rate		1.45%	1.45%			1.45%
DTE Electric \| 1.35% Revenue Bonds maturing in 2029 \| Tax Exempt Revenue Bonds
Debt Instrument [Line Items]
Face amount		$ 59,000,000	$ 59,000,000
Interest rate		1.35%	1.35%			1.45%

Long-Term Debt (Schedule of Deb

Long-Term Debt (Schedule of Debt Redeemed) (Details) - USD ($) $ in Millions	1 Months Ended					2 Months Ended	3 Months Ended		9 Months Ended
	Aug. 31, 2021	Jul. 31, 2021	Jun. 30, 2021	May 31, 2021	Apr. 30, 2021	Aug. 31, 2021	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Debt Instrument, Redemption [Line Items]
Amount						$ 2,600			$ 3,242	$ 682
Loss on extinguishment of debt							$ 376	$ 0	384	0
Junior Subordinated Debentures \| 5.375% Junior Subordinated Debentures maturing in 2076
Debt Instrument, Redemption [Line Items]
Interest rate			5.375%
Amount			$ 300
Loss on extinguishment of debt			$ 8
Senior Notes
Debt Instrument, Redemption [Line Items]
Amount							$ 2,600
Senior Notes \| 3.30% Senior Notes maturing in 2022
Debt Instrument, Redemption [Line Items]
Interest rate		3.30%
Amount		$ 300
Senior Notes \| 2.60% Senior Notes maturing in 2022
Debt Instrument, Redemption [Line Items]
Interest rate		2.60%
Amount		$ 300
Senior Notes \| 3.70% Senior Notes maturing in 2023
Debt Instrument, Redemption [Line Items]
Interest rate		3.70%
Amount		$ 600
Senior Notes \| 3.85% Senior Notes maturing in 2023
Debt Instrument, Redemption [Line Items]
Interest rate	3.85%	3.85%				3.85%
Amount	$ 165	$ 135
Senior Notes \| 3.50% Senior Notes maturing in 2024
Debt Instrument, Redemption [Line Items]
Interest rate		3.50%
Amount		$ 350
Senior Notes \| 3.80% Senior Notes maturing in 2027
Debt Instrument, Redemption [Line Items]
Interest rate		3.80%
Amount		$ 350
Senior Notes \| 3.40% Senior Notes maturing in 2029
Debt Instrument, Redemption [Line Items]
Interest rate		3.40%
Amount		$ 21
Senior Notes \| 6.375% Senior Notes maturing in 2033
Debt Instrument, Redemption [Line Items]
Interest rate	6.375%	6.375%				6.375%
Amount	$ 209	$ 191
DTE Electric
Debt Instrument, Redemption [Line Items]
Amount									$ 321	$ 632
DTE Electric \| Mortgage Bonds \| 3.90% Mortgage bonds maturing in 2021
Debt Instrument, Redemption [Line Items]
Interest rate					3.90%
Amount					$ 250
DTE Electric \| Mortgage Bonds \| 7.00% Mortgage Bonds maturing in 2021
Debt Instrument, Redemption [Line Items]
Interest rate				7.00%
Amount				$ 33
DTE Electric \| Mortgage Bonds \| 6.90% Senior Notes Due In 2021
Debt Instrument, Redemption [Line Items]
Interest rate	6.90%					6.90%
Amount	$ 38

Short-Term Credit Arrangement_3

Short-Term Credit Arrangements and Borrowings (Details Textuals)	Sep. 30, 2021USD ($)	Jun. 30, 2021	Dec. 31, 2020USD ($)
DTE Electric
Short-term Debt [Line Items]
Ratio of indebtedness to net capital	0.51
DTE Gas
Short-term Debt [Line Items]
Ratio of indebtedness to net capital	0.46
DTE Energy
Short-term Debt [Line Items]
Ratio of indebtedness to net capital	0.66
DTE Energy \| Demand financing agreement
Short-term Debt [Line Items]
Maximum borrowing capacity, financing agreement	$ 300,000,000
Amount outstanding	4,000,000		$ 49,000,000
DTE Energy \| Demand financing agreement \| Demand financing agreement, indefinite term
Short-term Debt [Line Items]
Maximum borrowing capacity, financing agreement	100,000,000
Maximum additional margin financing	50,000,000
DTE Energy \| Demand financing agreement \| Demand financing agreement, expiring in 2022
Short-term Debt [Line Items]
Maximum borrowing capacity, financing agreement	$ 150,000,000
Maximum
Short-term Debt [Line Items]
Ratio of indebtedness to net capital	0.70	0.65

Short-Term Credit Arrangement_4

Short-Term Credit Arrangements and Borrowings (Details) $ in Millions	Sep. 30, 2021USD ($)
Availability under combined facilities
Maximum borrowing capacity	$ 2,657
Amounts outstanding	629
Net availability	2,028
DTE Electric
Availability under combined facilities
Maximum borrowing capacity	500
Amounts outstanding	159
Net availability	341
DTE Gas
Availability under combined facilities
Maximum borrowing capacity	300
Amounts outstanding	128
Net availability	172
DTE Energy
Availability under combined facilities
Maximum borrowing capacity	1,857
Amounts outstanding	342
Net availability	1,515
Revolver borrowings
Availability under combined facilities
Amounts outstanding	74
Revolver borrowings \| DTE Electric
Availability under combined facilities
Amounts outstanding	0
Revolver borrowings \| DTE Gas
Availability under combined facilities
Amounts outstanding	0
Revolver borrowings \| DTE Energy
Availability under combined facilities
Amounts outstanding	74
Commercial paper issuances
Availability under combined facilities
Amounts outstanding	287
Commercial paper issuances \| DTE Electric
Availability under combined facilities
Amounts outstanding	159
Commercial paper issuances \| DTE Gas
Availability under combined facilities
Amounts outstanding	128
Commercial paper issuances \| DTE Energy
Availability under combined facilities
Amounts outstanding	0
Letters of credit
Availability under combined facilities
Amounts outstanding	268
Letters of credit \| DTE Electric
Availability under combined facilities
Amounts outstanding	0
Letters of credit \| DTE Gas
Availability under combined facilities
Amounts outstanding	0
Letters of credit \| DTE Energy
Availability under combined facilities
Amounts outstanding	268
Unsecured revolving credit facility, expiring April 2025 \| Revolver borrowings
Availability under combined facilities
Maximum borrowing capacity	2,300
Unsecured revolving credit facility, expiring April 2025 \| Revolver borrowings \| DTE Electric
Availability under combined facilities
Maximum borrowing capacity	500
Unsecured revolving credit facility, expiring April 2025 \| Revolver borrowings \| DTE Gas
Availability under combined facilities
Maximum borrowing capacity	300
Unsecured revolving credit facility, expiring April 2025 \| Revolver borrowings \| DTE Energy
Availability under combined facilities
Maximum borrowing capacity	1,500
Unsecured Canadian revolving credit facility, expiring May 2023 \| Revolver borrowings
Availability under combined facilities
Maximum borrowing capacity	87
Unsecured Canadian revolving credit facility, expiring May 2023 \| Revolver borrowings \| DTE Electric
Availability under combined facilities
Maximum borrowing capacity	0
Unsecured Canadian revolving credit facility, expiring May 2023 \| Revolver borrowings \| DTE Gas
Availability under combined facilities
Maximum borrowing capacity	0
Unsecured Canadian revolving credit facility, expiring May 2023 \| Revolver borrowings \| DTE Energy
Availability under combined facilities
Maximum borrowing capacity	87
Unsecured letter of credit facility, expiring in February 2023 \| Letters of credit
Availability under combined facilities
Maximum borrowing capacity	150
Unsecured letter of credit facility, expiring in February 2023 \| Letters of credit \| DTE Electric
Availability under combined facilities
Maximum borrowing capacity	0
Unsecured letter of credit facility, expiring in February 2023 \| Letters of credit \| DTE Gas
Availability under combined facilities
Maximum borrowing capacity	0
Unsecured letter of credit facility, expiring in February 2023 \| Letters of credit \| DTE Energy
Availability under combined facilities
Maximum borrowing capacity	150
Unsecured letter of credit facility, expiring in July 2023 \| Letters of credit
Availability under combined facilities
Maximum borrowing capacity	70
Unsecured letter of credit facility, expiring in July 2023 \| Letters of credit \| DTE Electric
Availability under combined facilities
Maximum borrowing capacity	0
Unsecured letter of credit facility, expiring in July 2023 \| Letters of credit \| DTE Gas
Availability under combined facilities
Maximum borrowing capacity	0
Unsecured letter of credit facility, expiring in July 2023 \| Letters of credit \| DTE Energy
Availability under combined facilities
Maximum borrowing capacity	70
Unsecured letter of credit facility \| Letters of credit
Availability under combined facilities
Maximum borrowing capacity	50
Unsecured letter of credit facility \| Letters of credit \| DTE Electric
Availability under combined facilities
Maximum borrowing capacity	0
Unsecured letter of credit facility \| Letters of credit \| DTE Gas
Availability under combined facilities
Maximum borrowing capacity	0
Unsecured letter of credit facility \| Letters of credit \| DTE Energy
Availability under combined facilities
Maximum borrowing capacity	50
Unsecured revolving credit facility, expiring April 2024 \| Revolver borrowings
Availability under combined facilities
Maximum borrowing capacity	102
Unsecured revolving credit facility, expiring April 2024 \| Revolver borrowings \| DTE Electric
Availability under combined facilities
Maximum borrowing capacity	22
Unsecured revolving credit facility, expiring April 2024 \| Revolver borrowings \| DTE Gas
Availability under combined facilities
Maximum borrowing capacity	13
Unsecured revolving credit facility, expiring April 2024 \| Revolver borrowings \| DTE Energy
Availability under combined facilities
Maximum borrowing capacity	$ 67

Leases (Details Textuals)

Leases (Details Textuals) - USD ($) $ in Millions	3 Months Ended			9 Months Ended
Leases (Details Textuals) - USD ($) $ in Millions	Sep. 30, 2021	Mar. 31, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Leases [Abstract]
Additional net investment in finance leases		$ 31
Interest income recognized under finance leases	$ 4		$ 4	$ 13	$ 12

Leases (Components of Net Inves

Leases (Components of Net Investment in Finance Leases) (Details) $ in Millions	Sep. 30, 2021USD ($)
Leases [Abstract]
2021	$ 6
2022	22
2023	22
2024	22
2025	22
2026 and Thereafter	292
Total minimum future lease receipts	386
Residual value of leased pipeline	17
Less unearned income	202
Net investment in finance lease	201
Less current portion	7
Net investment in finance lease, noncurrent	$ 194

Leases (Lease Income Associated

Leases (Lease Income Associated with Operating Leases) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Lessor, Lease, Description [Line Items]
Fixed payments	$ 13	$ 14	$ 42	$ 43
Variable payments	55	43	90	82
Total lease income under operating leases	68	57	132	125
Operating revenues
Lessor, Lease, Description [Line Items]
Total lease income under operating leases	26	26	70	74
Other income
Lessor, Lease, Description [Line Items]
Total lease income under operating leases	$ 42	$ 31	$ 62	$ 51

Commitments and Contingencies (

Commitments and Contingencies (Details Textuals)	1 Months Ended	9 Months Ended
Commitments and Contingencies (Details Textuals)	Jun. 30, 2020	Sep. 30, 2021USD ($)employeefacilitysite	Dec. 31, 2020USD ($)
Loss Contingencies [Line Items]
Estimated capital expenditures and contributions to equity method investees for current fiscal year		$ 3,900,000,000
Workforce subject to collective bargaining arrangements \| Labor force concentration risk
Loss Contingencies [Line Items]
Number of employees \| employee		5,100
Percentage of total employees		50.00%
Workforce Subject to Collective Bargaining Arrangements Expiring within One Year \| Labor force concentration risk
Loss Contingencies [Line Items]
Percentage of total employees		16.00%
Synthetic fuel
Loss Contingencies [Line Items]
Number of days after expiration of statutes of limitations		90 days
Maximum potential liability		$ 400,000,000
Reduced emissions fuel guarantees
Loss Contingencies [Line Items]
Number of days after expiration of statutes of limitations		90 days
Maximum potential liability		$ 698,000,000
Other guarantees
Loss Contingencies [Line Items]
Maximum potential liability		40,000,000
Performance surety bonds
Loss Contingencies [Line Items]
Performance bonds outstanding		$ 171,000,000
Reduction of Carbon Emissions by 2023
Loss Contingencies [Line Items]
Commitment to reduce carbon emissions, percentage		32.00%
Reduction of Carbon Emissions by 2028
Loss Contingencies [Line Items]
Commitment to reduce carbon emissions, percentage		50.00%
Reduction of Carbon Emissions by 2040
Loss Contingencies [Line Items]
Commitment to reduce carbon emissions, percentage		80.00%
DTE Electric
Loss Contingencies [Line Items]
Environmental capital expenditures		$ 2,400,000,000
Estimated environmental capital expenditures		$ 0
Number of former MGP sites \| site		3
Accrued for remediation		$ 13,000,000	$ 10,000,000
Number of permitted engineered ash storage facilities owned \| facility		3
Estimated capital expenditures and contributions to equity method investees for current fiscal year		$ 3,000,000,000
DTE Electric \| Workforce subject to collective bargaining arrangements \| Labor force concentration risk
Loss Contingencies [Line Items]
Number of employees \| employee		2,700
Percentage of total employees		57.00%
DTE Electric \| Workforce Subject to Collective Bargaining Arrangements Expiring within One Year \| Labor force concentration risk
Loss Contingencies [Line Items]
Percentage of total employees		21.00%
DTE Electric \| Performance surety bonds
Loss Contingencies [Line Items]
Performance bonds outstanding		$ 120,000,000
DTE Electric \| Reduction of Carbon Emissions by 2050
Loss Contingencies [Line Items]
Goal of net carbon emissions, percentage		0.00%
DTE Electric \| Coal Combustion Residual And Effluent Limitations Guidelines Rules
Loss Contingencies [Line Items]
Estimated impact of the CCR and ELG rules		$ 661,000,000
Estimated impact of the CCR and ELG rules through 2025		$ 516,000,000
DTE Gas
Loss Contingencies [Line Items]
Number of former MGP sites \| site		14
Accrued for remediation		$ 24,000,000	$ 24,000,000
Amortization period (in years)		10 years
DTE Gas \| Clean up completed and site closed
Loss Contingencies [Line Items]
Number of former MGP sites \| site		8
DTE Gas \| Partial closure complete
Loss Contingencies [Line Items]
Number of former MGP sites \| site		4
DTE Gas \| Reduction of Greenhouse Gas Emissions by 2050
Loss Contingencies [Line Items]
Goal of net greenhouse gas emissions, percentage	0.00%

Retirement Benefits and Trust_3

Retirement Benefits and Trusteed Assets (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Pension Benefits
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 27	$ 25	$ 81	$ 74
Interest cost	39	46	118	139
Expected return on plan assets	(84)	(84)	(254)	(250)
Amortization of net actuarial loss	49	43	147	129
Amortization of prior service credit	0	0	0	0
Settlements	0	2	0	2
Net periodic benefit cost (credit)	31	32	92	94
Other Postretirement Benefits
Defined Benefit Plan Disclosure [Line Items]
Service cost	8	7	23	20
Interest cost	12	14	35	42
Expected return on plan assets	(33)	(32)	(97)	(96)
Amortization of net actuarial loss	3	4	10	12
Amortization of prior service credit	(5)	(5)	(15)	(15)
Settlements	0	0	0	0
Net periodic benefit cost (credit)	(15)	(12)	(44)	(37)
Other Postretirement Benefits \| DTE Electric
Defined Benefit Plan Disclosure [Line Items]
Service cost	6	5	17	15
Interest cost	8	11	25	32
Expected return on plan assets	(22)	(21)	(65)	(65)
Amortization of net actuarial loss	3	2	9	8
Amortization of prior service credit	(3)	(3)	(10)	(10)
Net periodic benefit cost (credit)	$ (8)	$ (6)	$ (24)	$ (20)

Retirement Benefits and Trust_4

Retirement Benefits and Trusteed Assets (Details Textuals) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Pension plans \| Qualified Plan
Defined Benefit Plan Disclosure [Line Items]
Anticipated contributions, current fiscal year	$ 7,000,000		$ 7,000,000
Postretirement benefit plans
Defined Benefit Plan Disclosure [Line Items]
Anticipated contributions, current fiscal year	0		0
DTE Electric \| Pension plans
Defined Benefit Plan Disclosure [Line Items]
Pension cost	26,000,000	$ 28,000,000	78,000,000	$ 79,000,000
DTE Electric \| Pension plans \| Qualified Plan
Defined Benefit Plan Disclosure [Line Items]
Anticipated contributions, current fiscal year	$ 0		$ 0

Segment and Related Informati_3

Segment and Related Information (Details Textuals) customer in Millions	Sep. 30, 2021customer
Segment Reporting [Abstract]
Number of electric utility customers	2.3
Number of gas utility customers	1.3

Segment and Related Informati_4

Segment and Related Information (Financial Data - Inter-segment Billing) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Segment Reporting Information [Line Items]
Operating Revenues	$ (3,715)	$ (3,080)	$ (10,317)	$ (8,343)
Electric
Segment Reporting Information [Line Items]
Operating Revenues	(1,702)	(1,693)	(4,477)	(4,221)
Gas
Segment Reporting Information [Line Items]
Operating Revenues	(193)	(173)	(1,070)	(964)
DTE Vantage
Segment Reporting Information [Line Items]
Operating Revenues	(372)	(324)	(1,132)	(850)
Energy Trading
Segment Reporting Information [Line Items]
Operating Revenues	(1,602)	(1,061)	(4,208)	(2,714)
Reconciliation and Eliminations
Segment Reporting Information [Line Items]
Operating Revenues	155	164	558	391
Reconciliation and Eliminations \| Electric
Segment Reporting Information [Line Items]
Operating Revenues	17	16	48	46
Reconciliation and Eliminations \| Gas
Segment Reporting Information [Line Items]
Operating Revenues	3	4	10	12
Reconciliation and Eliminations \| DTE Vantage
Segment Reporting Information [Line Items]
Operating Revenues	125	134	463	308
Reconciliation and Eliminations \| Energy Trading
Segment Reporting Information [Line Items]
Operating Revenues	9	9	35	23
Reconciliation and Eliminations \| Corporate and Other
Segment Reporting Information [Line Items]
Operating Revenues	$ 1	$ 1	$ 2	$ 2

Segment and Related Informati_5

Segment and Related Information (Financial Data - Operating Revenues including Inter-segment Revenues) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Segment Reporting, Revenue Reconciling Item [Line Items]
Operating Revenues — Utility operations	$ 1,875	$ 1,844	$ 5,483	$ 5,119
Operating Revenues — Non-utility operations	1,840	1,236	4,834	3,224
Operating Revenues	3,715	3,080	10,317	8,343
Reconciliation and Eliminations
Segment Reporting, Revenue Reconciling Item [Line Items]
Operating Revenues — Non-utility operations	(155)	(172)	(572)	(408)
Operating Revenues	(155)	(164)	(558)	(391)
Electric
Segment Reporting, Revenue Reconciling Item [Line Items]
Operating Revenues	1,702	1,693	4,477	4,221
Electric \| Operating segments
Segment Reporting, Revenue Reconciling Item [Line Items]
Operating Revenues — Utility operations	1,700	1,690	4,468	4,211
Operating Revenues — Non-utility operations	2	3	9	10
Electric \| Reconciliation and Eliminations
Segment Reporting, Revenue Reconciling Item [Line Items]
Operating Revenues	(17)	(16)	(48)	(46)
Gas
Segment Reporting, Revenue Reconciling Item [Line Items]
Operating Revenues	193	173	1,070	964
Gas \| Operating segments
Segment Reporting, Revenue Reconciling Item [Line Items]
Operating Revenues — Utility operations	193	173	1,070	964
Gas \| Reconciliation and Eliminations
Segment Reporting, Revenue Reconciling Item [Line Items]
Operating Revenues	(3)	(4)	(10)	(12)
DTE Vantage
Segment Reporting, Revenue Reconciling Item [Line Items]
Operating Revenues	372	324	1,132	850
DTE Vantage \| Operating segments
Segment Reporting, Revenue Reconciling Item [Line Items]
Operating Revenues — Non-utility operations	372	324	1,132	850
DTE Vantage \| Reconciliation and Eliminations
Segment Reporting, Revenue Reconciling Item [Line Items]
Operating Revenues	(125)	(134)	(463)	(308)
Energy Trading
Segment Reporting, Revenue Reconciling Item [Line Items]
Operating Revenues	1,602	1,061	4,208	2,714
Energy Trading \| Operating segments
Segment Reporting, Revenue Reconciling Item [Line Items]
Operating Revenues — Non-utility operations	1,602	1,061	4,208	2,714
Energy Trading \| Reconciliation and Eliminations
Segment Reporting, Revenue Reconciling Item [Line Items]
Operating Revenues	(9)	(9)	(35)	(23)
Corporate and Other \| Operating segments
Segment Reporting, Revenue Reconciling Item [Line Items]
Operating Revenues — Non-utility operations	1	1	2	2
Corporate and Other \| Reconciliation and Eliminations
Segment Reporting, Revenue Reconciling Item [Line Items]
Operating Revenues	$ (1)	(1)	(2)	(2)
Gas Storage and Pipelines \| Reconciliation and Eliminations
Segment Reporting, Revenue Reconciling Item [Line Items]
Operating Revenues — Non-utility operations		$ 8	$ 14	$ 17

Segment and Related Informati_6

Segment and Related Information (Financial Data - Net Income (Loss) Attributable to DTE Energy by Segment) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Net Income (Loss) attributable to DTE Energy — continuing operations	$ 58	$ 372	$ 495	$ 844
Net Income (Loss) attributable to DTE Energy — discontinued operations	(33)	104	106	249
Net Income Attributable to DTE Energy Company/DTE Electric Company	25	476	601	1,093
Electric
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Net Income (Loss) attributable to DTE Energy — continuing operations	342	398	788	675
Gas
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Net Income (Loss) attributable to DTE Energy — continuing operations	(30)	(20)	146	102
DTE Vantage
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Net Income (Loss) attributable to DTE Energy — continuing operations	73	47	115	102
Energy Trading
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Net Income (Loss) attributable to DTE Energy — continuing operations	(52)	(28)	(173)	5
Corporate and Other
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Net Income (Loss) attributable to DTE Energy — continuing operations	$ (275)	$ (25)	$ (381)	$ (40)