Leases (Finance Leases Reported on Consolidated Statements of Financial Position) (Details) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019
Lessee, Lease, Description [Line Items]
Finance Lease, Right-of-Use Asset, Statement of Financial Position [Extensible List]	us-gaap:PropertyPlantAndEquipmentNet	us-gaap:PropertyPlantAndEquipmentNet
Right-of-use assets, within Property, plant, and equipment, net	$ 29	$ 15
Finance Lease, Liability, Current, Statement of Financial Position [Extensible List]	us-gaap:OtherLiabilitiesCurrent	us-gaap:OtherLiabilitiesCurrent
Current lease liabilities, within Current Liabilities — Other	$ 7	$ 4
Long-term lease liabilities	24	11
DTE Electric
Lessee, Lease, Description [Line Items]
Right-of-use assets, within Property, plant, and equipment, net	16	7
Current lease liabilities, within Current Liabilities — Other	6	3
Long-term lease liabilities	$ 13	$ 4