Short-Term Credit Arrangements and Borrowings (Tables)

9 Months Ended

Sep. 30, 2017

Short-term Debt [Abstract]

Schedule of Line of Credit Facilities

The availability under the facilities in place at September 30, 2017 is shown in the following table:

	DTE Energy		DTE Electric		DTE Gas		Total
	(In millions)
Unsecured letter of credit facility, expiring in February 2019	$	150	$	—	$	—	$	150
Unsecured letter of credit facility, expiring in September 2019(a)	70		—		—		70
Unsecured revolving credit facility, expiring April 2022	1,200		400		300		1,900
	1,420		400		300		2,120
Amounts outstanding at September 30, 2017
Commercial paper issuances	98		311		250		659
Letters of credit	132		—		—		132
	230		311		250		791
Net availability at September 30, 2017	$	1,190	$	89	$	50	$	1,329

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(a) In August 2017, DTE Energy amended its $70 million letter of credit facility. The facility's maturity date was extended from September 2017 to September 2019.