Income Taxes (Details Textuals) - USD ($)	3 Months Ended	12 Months Ended
	Jun. 30, 2020	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Entity Information [Line Items]
Deferred tax asset, general business tax credit carryforwards		$ 1,100,000,000
State and local net operating loss carry-forwards		155,000,000	$ 117,000,000
Valuation allowance		41,000,000	40,000,000
Unrecognized tax benefits that would impact effective tax rate		8,000,000	8,000,000
Interest on income taxes accrued		5,000,000	4,000,000
Interest on income taxes expense		1,000,000	1,000,000	$ 1,000,000
Penalties on income taxes accrued		0	0
CARES Act
Entity Information [Line Items]
Reduction in Income Tax Expense due to carryback of 2018 net operating loss to 2013		34,000,000
Claim for employee retention credits	$ 6,000,000
Deferral of employer payroll taxes		44,000,000
CARES Act, AMT Credit Refund
Entity Information [Line Items]
AMT credit received from U.S. Treasury		220,000,000
Immediate Refund of 2018 Remaining AMT Credit Balance
Entity Information [Line Items]
AMT credit received from U.S. Treasury		153,000,000
Immediate Refund of AMT Credit Generated by Carrying Back 2018 Net Operating Loss to 2013
Entity Information [Line Items]
AMT credit received from U.S. Treasury		67,000,000
Federal
Entity Information [Line Items]
Net operating loss carry-forwards		1,300,000,000
DTE Electric
Entity Information [Line Items]
Income tax receivable from related party		8,000,000	14,000,000
State and local net operating loss carry-forwards		0	0
Valuation allowance		0	0
Unrecognized tax benefits that would impact effective tax rate		10,000,000	10,000,000
Interest on income taxes accrued		6,000,000	6,000,000
Interest on income taxes expense		0	1,000,000	$ 1,000,000
Penalties on income taxes accrued		0	$ 0
DTE Electric | CARES Act
Entity Information [Line Items]
Claim for employee retention credits	$ 3,000,000
Deferral of employer payroll taxes		23,000,000
DTE Electric | General Business Credits
Entity Information [Line Items]
Tax credit carry-forward		$ 278,000,000