Financial and Other Derivative Instruments (Details Textuals) - USD ($) $ in Millions	Sep. 30, 2026	Dec. 31, 2025
Derivatives, Fair Value [Line Items]
Total derivative assets, gross	$ 1,056	$ 707
Letters of credit issued that could be used to offset net derivative liabilities	2	2
Letters of credit received that could be used to offset net derivative assets	8	17
Contractual obligation to post collateral in event of downgrade to below investment grade	370
Derivative net liability position aggregate fair value	889
Collateral already posted fair value	33
Derivative net asset position, fair value	736
Remaining amount of offsets to derivative net liability positions for hard and soft trigger provisions	120
Derivatives not designated as hedging instruments
Derivatives, Fair Value [Line Items]
Total derivative assets, gross	1,013	704
Balance Sheet Location [Axis]: us-gaap:DerivativeAssetsCurrent
Derivatives, Fair Value [Line Items]
Total derivative assets, gross	732	482
Balance Sheet Location [Axis]: us-gaap:DerivativeAssetsNoncurrent
Derivatives, Fair Value [Line Items]
Total derivative assets, gross	324	225
Balance Sheet Location [Axis]: us-gaap:OtherAssetsCurrent | Derivative assets — FTRs | Derivatives not designated as hedging instruments | DTE Electric
Derivatives, Fair Value [Line Items]
Total derivative assets, gross	$ 30	$ 11