Fair Value (Fair Value and Unrealized Gains and Losses for Nuclear Decommissioning Trust Funds) (Details) - USD ($) $ in Millions	Sep. 30, 2026	Dec. 31, 2025
Cash equivalents
Debt Securities, Available-for-sale [Line Items]
Fair Value	$ 37	$ 35
Private equity and other
Debt Securities, Available-for-sale [Line Items]
Fair Value	381	358
Hedge funds and similar investments
Debt Securities, Available-for-sale [Line Items]
Fair Value	258	245
Equity securities
Debt Securities, Available-for-sale [Line Items]
Fair Value	1,252	1,188
Fixed income securities
Debt Securities, Available-for-sale [Line Items]
Fair Value	778	726
DTE Electric
Debt Securities, Available-for-sale [Line Items]
Fair Value	2,706	2,552
Unrealized Gains	981	900
Unrealized Losses	(78)	(40)
DTE Electric | Cash equivalents
Debt Securities, Available-for-sale [Line Items]
Fair Value	37	35
Unrealized Gains	0	0
Unrealized Losses	0	0
DTE Electric | Private equity and other
Debt Securities, Available-for-sale [Line Items]
Fair Value	381	358
Unrealized Gains	133	125
Unrealized Losses	(10)	(7)
DTE Electric | Hedge funds and similar investments
Debt Securities, Available-for-sale [Line Items]
Fair Value	258	245
Unrealized Gains	9	8
Unrealized Losses	(10)	(6)
DTE Electric | Equity securities
Debt Securities, Available-for-sale [Line Items]
Fair Value	1,252	1,188
Unrealized Gains	820	742
Unrealized Losses	(13)	(10)
DTE Electric | Fixed income securities
Debt Securities, Available-for-sale [Line Items]
Fair Value	778	726
Unrealized Gains	19	25
Unrealized Losses	$ (45)	$ (17)