Fair Value (Fair Value and Unrealized Gains and Losses for Nuclear Decommissioning Trust Funds) (Details) - USD ($) $ in Millions	Dec. 31, 2025	Dec. 31, 2024
Cash equivalents
Debt Securities, Available-for-sale [Line Items]
Fair Value	$ 35	$ 26
Private Equity and Other
Debt Securities, Available-for-sale [Line Items]
Fair Value	358	349
Hedge Funds and Similar Investments
Debt Securities, Available-for-sale [Line Items]
Fair Value	245	228
Equity securities
Debt Securities, Available-for-sale [Line Items]
Fair Value	1,188	1,003
Fixed Income Securities
Debt Securities, Available-for-sale [Line Items]
Fair Value	726	650
DTE Electric
Debt Securities, Available-for-sale [Line Items]
Fair Value	2,552	2,256
Unrealized Gains	900	687
Unrealized Losses	(40)	(58)
DTE Electric | Cash equivalents
Debt Securities, Available-for-sale [Line Items]
Fair Value	35	26
Unrealized Gains	0	0
Unrealized Losses	0	0
DTE Electric | Private Equity and Other
Debt Securities, Available-for-sale [Line Items]
Fair Value	358	349
Unrealized Gains	125	106
Unrealized Losses	(7)	(8)
DTE Electric | Hedge Funds and Similar Investments
Debt Securities, Available-for-sale [Line Items]
Fair Value	245	228
Unrealized Gains	8	7
Unrealized Losses	(6)	(5)
DTE Electric | Equity securities
Debt Securities, Available-for-sale [Line Items]
Fair Value	1,188	1,003
Unrealized Gains	742	558
Unrealized Losses	(10)	(16)
DTE Electric | Fixed Income Securities
Debt Securities, Available-for-sale [Line Items]
Fair Value	726	650
Unrealized Gains	25	16
Unrealized Losses	$ (17)	$ (29)