Acquisitions (Details Textuals) $ in Millions			1 Months Ended	9 Months Ended
	Sep. 20, 2019 USD ($)	Sep. 12, 2019 USD ($) MW	Jan. 31, 2020 USD ($)	Sep. 30, 2019 USD ($)	Sep. 30, 2018 USD ($)
Business Acquisition [Line Items]
Consideration paid for entity acquired, paid in cash				$ 174	$ 0
Electric | Heritage Sustainable Energy, Renewable Energy Project
Business Acquisition [Line Items]
Amount of power associated with purchase of renewable energy project | MW		89
Consideration paid for entity acquired, paid in cash		$ 174
Electric | Heritage Sustainable Energy, Renewable Energy Project | Minimum
Business Acquisition [Line Items]
Customer relationship intangible assets, amortization period		11 years
Electric | Heritage Sustainable Energy, Renewable Energy Project | Maximum
Business Acquisition [Line Items]
Customer relationship intangible assets, amortization period		14 years
Electric | Heritage Sustainable Energy, Additional Renewable Energy Project | Forecast
Business Acquisition [Line Items]
Total consideration paid for acquired entity			$ 30
Gas Storage and Pipelines | Generation Pipeline, LLC
Business Acquisition [Line Items]
Portion of consideration paid attributable to DTE Energy	50.00%
Gas Storage and Pipelines | Generation Pipeline, LLC | NEXUS
Business Acquisition [Line Items]
Total consideration paid for acquired entity	$ 163