Retirement Benefits and Trusteed Assets (Tables)

3 Months Ended

Mar. 31, 2016

Defined Benefit Pension Plans and Defined Benefit Postretirement Plans Disclosure [Abstract]

Schedule of Net Benefit Costs

The following table details the components of net periodic benefit costs for pension benefits and other postretirement benefits for DTE Energy:

	Pension Benefits						Other Postretirement Benefits
	2016			2015			2016			2015
Three Months Ended March 31,	(In millions)
Service cost	$	23		$	25		$	6		$	9
Interest cost	54			53			20			20
Expected return on plan assets	(77		)	(74		)	(32		)	(33		)
Amortization of:
Net actuarial loss	40			51			8			11
Prior service credit	—			—			(30		)	(31		)
Net periodic benefit cost (credit)	$	40		$	55		$	(28	)	$	(24	)

The following table details the components of net periodic benefit costs for pension benefits and other postretirement benefits for DTE Electric:

	Pension Benefits						Other Postretirement Benefits
	2016			2015			2016			2015
Three Months Ended March 31,	(In millions)
Service cost	$	18		$	20		$	5		$	7
Interest cost	41			40			15			16
Expected return on plan assets	(55		)	(53		)	(23		)	(23		)
Amortization of:
Net actuarial loss	29			38			6			8
Prior service credit	—			—			(22		)	(24		)
Net periodic benefit cost (credit)	$	33		$	45		$	(19	)	$	(16	)