Short-Term Credit Arrangements and Borrowings (Tables)

12 Months Ended

Dec. 31, 2017

Short-term Debt [Abstract]

Schedule of Line of Credit Facilities

The availability under the facilities in place at December 31, 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	70		—		—		70
Unsecured revolving credit facility, expiring April 2022	1,200		400		300		1,900
	1,420		400		300		2,120
Amounts outstanding at December 31, 2017
Commercial paper issuances	83		238		300		621
Letters of credit	124		—		—		124
	207		238		300		745
Net availability at December 31, 2017	$	1,213	$	162	$	—	$	1,375