Significant Accounting Policies (Tables)

9 Months Ended

Sep. 30, 2019

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,
	2019		2018		2019		2018
	(In millions)
Income from REF entities	$	40	$	27	$	96	$	75
Equity earnings of equity method investees	34		46		77		99
Gains from equity securities	3		5		27		6
Contract services	7		11		21		43
Allowance for equity funds used during construction	5		7		18		20
Other	9		3		20		19
	$	98	$	99	$	259	$	262

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

	Three Months Ended September 30,				Nine Months Ended September 30,
	2019		2018		2019		2018
	(In millions)
Gains from equity securities allocated from DTE Energy	$	3	$	5	$	27	$	6
Contract services	7		11		23		44
Allowance for equity funds used during construction	5		5		17		14
Other	5		2		11		8
	$	20	$	23	$	78	$	72

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,
	2019		2018		2019		2018
DTE Energy	13	%	9	%	12	%	12	%
DTE Electric	16	%	21	%	16	%	22	%

Schedule of Finite-Lived Intangible Assets by Major Class

The Registrants have certain Intangible assets as shown below:

		September 30, 2019							December 31, 2018
	Useful Lives	Gross Carrying Value		Accumulated Amortization			Net Carrying Value		Gross Carrying Value		Accumulated Amortization			Net Carrying Value
		(In millions)
Intangible assets subject to amortization
Customer relationships	25 to 40 years(a)	$	779	$	(58	)	$	721	$	779	$	(44	)	$	735
Contract intangibles	6 to 26 years	270		(72		)	198		159		(66		)	93
		1,049		(130		)	919		938		(110		)	828
DTE Electric renewable energy credits	(b)	20		—			20		20		—			20
DTE Electric emission allowances	(b)	1		—			1		1		—			1
		21		—			21		21		—			21
Long-term intangible assets
DTE Electric		$	21	$	—		$	21	$	21	$	—		$	21
DTE Energy		$	1,070	$	(130	)	$	940	$	959	$	(110	)	$	849

______________________________________

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

(b)

Emission allowances and renewable energy credits are charged to expense, using average cost, as the allowances and credits are consumed in the operation of the business.

Schedule of Indefinite-Lived Intangible Assets

The Registrants have certain Intangible assets as shown below:

		September 30, 2019							December 31, 2018
	Useful Lives	Gross Carrying Value		Accumulated Amortization			Net Carrying Value		Gross Carrying Value		Accumulated Amortization			Net Carrying Value
		(In millions)
Intangible assets subject to amortization
Customer relationships	25 to 40 years(a)	$	779	$	(58	)	$	721	$	779	$	(44	)	$	735
Contract intangibles	6 to 26 years	270		(72		)	198		159		(66		)	93
		1,049		(130		)	919		938		(110		)	828
DTE Electric renewable energy credits	(b)	20		—			20		20		—			20
DTE Electric emission allowances	(b)	1		—			1		1		—			1
		21		—			21		21		—			21
Long-term intangible assets
DTE Electric		$	21	$	—		$	21	$	21	$	—		$	21
DTE Energy		$	1,070	$	(130	)	$	940	$	959	$	(110	)	$	849

______________________________________

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

(b)

Emission allowances and renewable energy credits are charged to expense, using average cost, as the allowances and credits are consumed in the operation of the business.

Schedule of Finite-Lived Intangible Assets, Future Amortization Expense

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

	Remaining
	2019		2020		2021		2022		2023		2024
	(In millions)
Estimated amortization expense	$	9	$	35	$	34	$	34	$	34	$	34