Fair Value (Fair Value and Unrealized Gains and Losses for Nuclear Decommissioning Trust Funds) (Details) - DTE Electric - USD ($) $ in Millions	Sep. 30, 2025	Dec. 31, 2024
Debt Securities, Available-for-sale [Line Items]
Fair Value	$ 2,480	$ 2,256
Unrealized Gains	840	687
Unrealized Losses	(41)	(58)
Cash equivalents
Debt Securities, Available-for-sale [Line Items]
Fair Value	31	26
Unrealized Gains	0	0
Unrealized Losses	0	0
Private equity and other
Debt Securities, Available-for-sale [Line Items]
Fair Value	362	349
Unrealized Gains	122	106
Unrealized Losses	(9)	(8)
Hedge funds and similar investments
Debt Securities, Available-for-sale [Line Items]
Fair Value	241	228
Unrealized Gains	6	7
Unrealized Losses	(5)	(5)
Equity securities
Debt Securities, Available-for-sale [Line Items]
Fair Value	1,139	1,003
Unrealized Gains	694	558
Unrealized Losses	(9)	(16)
Fixed income securities
Debt Securities, Available-for-sale [Line Items]
Fair Value	707	650
Unrealized Gains	18	16
Unrealized Losses	$ (18)	$ (29)