Long-Term Debt (Tables)

12 Months Ended

Dec. 31, 2017

Long-term Debt, Unclassified [Abstract]

Schedule of Long-term Debt Instruments

At December 31, 2017, DTE Energy had the following Junior Subordinated Debentures:

	Interest Rate	Maturity Date	Amount
			(In millions)
2012 Series C	5.25%	2062	$	200
2016 Series B	5.375%	2076	300
2016 Series F	6.00%	2076	280
2017 Series E	5.25%	2077	400
			$	1,180

Selected information about DTE Energy’s 2016 Equity Units is presented below:

Issuance Date	Units Issued	Total Net Proceeds		Total Long-Term Debt		RSN Annual Interest Rate	Stock Purchase Contract Annual Rate	Stock Purchase Settlement Date	Stock Purchase Contract Liability(a)		RSN Maturity Date
(In millions, except interest rates)
10/5/2016	13.5	$	654	$	675	1.5%	5.0%	10/1/2019	$	98	10/1/2024

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(a) Payments of $32 million were made in 2017. The stock purchase contract liability was $66 million and $98 million at December 31, 2017 and 2016, respectively, exclusive of interest.

DTE Energy's long-term debt outstanding and weighted average interest rates of debt outstanding at December 31 were:

	Interest Rate(a)	Maturity Date	2017			2016
			(In millions)
Mortgage bonds, notes, and other
DTE Energy Debt, Unsecured	3.1%	2019 — 2033	$	3,825		$	3,325
DTE Electric Taxable Debt, Principally Secured	4.3%	2020 — 2047	5,755			5,615
DTE Electric Tax-Exempt Revenue Bonds(b)	4.3%	2020 — 2030	310			310
DTE Gas Taxable Debt, Principally Secured	4.8%	2018 — 2047	1,330			1,250
Other Long-Term Debt, including Non-Recourse Debt			7			92
			11,227			10,592
Unamortized debt discount and premium, net			(15		)	(10		)
Unamortized debt issuance costs			(69		)	(67		)
Long-term debt due within one year			(104		)	(9		)
			$	11,039		$	10,506
Junior Subordinated Debentures
Subordinated Debentures	5.5%	2062 — 2077	$	1,180		$	780
Unamortized debt issuance costs			(35		)	(24		)
			$	1,145		$	756

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(a) Weighted average interest rate as of December 31, 2017.

(b) DTE Electric Tax-Exempt Revenue Bonds are issued by a public body that loans the proceeds to DTE Electric on terms substantially mirroring the Revenue Bonds.

DTE Electric's long-term debt outstanding and weighted average interest rates of debt outstanding at December 31 were:

	Interest Rate(a)	Maturity Date	2017			2016
			(In millions)
Mortgage bonds, notes, and other
Taxable Debt, Principally Secured	4.3%	2020 — 2047	$	5,755		$	5,615
Tax-Exempt Revenue Bonds(b)	4.3%	2020 — 2030	310			310
			6,065			5,925
Unamortized debt discount			(10		)	(10		)
Unamortized debt issuance costs			(38		)	(37		)
			$	6,017		$	5,878

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(a) Weighted average interest rate as of December 31, 2017.

(b) Tax-Exempt Revenue Bonds are issued by a public body that loans the proceeds to DTE Electric on terms substantially mirroring the Revenue Bonds.

Schedule of Issued Debt

In 2017, the following debt was issued:

Company	Month	Type	Interest Rate	Maturity Date	Amount
					(In millions)
DTE Energy	March	Senior Notes(a)	3.80%	2027	$	500
DTE Electric	August	General and Refunding Mortgage Bonds(b)	3.75%	2047	440
DTE Gas	September	First Mortgage Bonds(a)	3.08%	2029	40
DTE Gas	September	First Mortgage Bonds(a)	3.75%	2047	40
DTE Energy	November	Junior Subordinated Debentures(a)	5.25%	2077	400
					$	1,420

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(a) Proceeds were used for repayment of short-term borrowings and general corporate purposes.

(b) Proceeds were used to repay $300 million of DTE Electric's 2008 series G 5.60% Senior Notes due on June 15, 2018, for the repayment of short-term borrowings and general corporate purposes.

Schedule of Debt Redeemed

In 2017, the following debt was redeemed:

Company	Month	Type	Interest Rate	Maturity Date	Amount
					(In millions)
DTE Electric	August	Senior Notes	5.60%	2018	$	300
DTE Energy	September	Secured Note(a)	7.29%	2029	77
DTE Energy	Various	Other Long-Term Debt	Various	2017	8
					$	385

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(a) DTE Energy's Gas Storage and Pipelines segment recognized a $16 million net loss on extinguishment of debt associated with early repayment, consisting of $20 million of early redemption premiums and $4 million of unamortized debt premiums. The loss is reflected in Other (Income) and Deductions — Interest Expense on the Consolidated Statements of Operations.

Schedule of Maturities of Long-term Debt

The following table shows the Registrants' scheduled debt maturities, excluding any unamortized discount or premium on debt:

	2018		2019		2020		2021		2022		2023 and Thereafter		Total
	(In millions)
DTE Energy(a)	$	104	$	1,497	$	683	$	462	$	616	$	9,045	$	12,407
DTE Electric	$	—	$	—	$	632	$	462	$	316	$	4,655	$	6,065

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(a) Amounts include DTE Electric's scheduled debt maturities.