Retirement Benefits and Trusteed Assets (Fair Value Measurement Amounts for Other Postretirement Benefit Plan Assets) (Details) - Other postretirement benefit plan - USD ($) $ in Millions	Dec. 31, 2025	Dec. 31, 2024	Dec. 31, 2023
Defined Benefit Plan Disclosure [Line Items]
Total	$ 1,654	$ 1,594	$ 1,614
Level 1
Defined Benefit Plan Disclosure [Line Items]
Total	247	276
Level 2
Defined Benefit Plan Disclosure [Line Items]
Total	589	529
Other
Defined Benefit Plan Disclosure [Line Items]
Total	818	789
Short-term Investments
Defined Benefit Plan Disclosure [Line Items]
Total	37	33
Short-term Investments | Level 1
Defined Benefit Plan Disclosure [Line Items]
Total	37	33
Short-term Investments | Level 2
Defined Benefit Plan Disclosure [Line Items]
Total	0	0
Short-term Investments | Other
Defined Benefit Plan Disclosure [Line Items]
Total	0	0
Equity Securities, Domestic
Defined Benefit Plan Disclosure [Line Items]
Total	61	67
Equity Securities, Domestic | Level 1
Defined Benefit Plan Disclosure [Line Items]
Total	0	0
Equity Securities, Domestic | Level 2
Defined Benefit Plan Disclosure [Line Items]
Total	0	0
Equity Securities, Domestic | Other
Defined Benefit Plan Disclosure [Line Items]
Total	61	67
Equity Securities, International
Defined Benefit Plan Disclosure [Line Items]
Total	49	40
Equity Securities, International | Level 1
Defined Benefit Plan Disclosure [Line Items]
Total	7	6
Equity Securities, International | Level 2
Defined Benefit Plan Disclosure [Line Items]
Total	0	0
Equity Securities, International | Other
Defined Benefit Plan Disclosure [Line Items]
Total	42	34
Fixed Income Securities, Governmental
Defined Benefit Plan Disclosure [Line Items]
Total	206	244
Fixed Income Securities, Governmental | Level 1
Defined Benefit Plan Disclosure [Line Items]
Total	169	210
Fixed Income Securities, Governmental | Level 2
Defined Benefit Plan Disclosure [Line Items]
Total	37	34
Fixed Income Securities, Governmental | Other
Defined Benefit Plan Disclosure [Line Items]
Total	0	0
Fixed Income Securities, Corporate
Defined Benefit Plan Disclosure [Line Items]
Total	771	700
Fixed Income Securities, Corporate | Level 1
Defined Benefit Plan Disclosure [Line Items]
Total	0	0
Fixed Income Securities, Corporate | Level 2
Defined Benefit Plan Disclosure [Line Items]
Total	549	492
Fixed Income Securities, Corporate | Other
Defined Benefit Plan Disclosure [Line Items]
Total	222	208
Hedge Funds and Similar Investments
Defined Benefit Plan Disclosure [Line Items]
Total	142	133
Hedge Funds and Similar Investments | Level 1
Defined Benefit Plan Disclosure [Line Items]
Total	34	27
Hedge Funds and Similar Investments | Level 2
Defined Benefit Plan Disclosure [Line Items]
Total	3	3
Hedge Funds and Similar Investments | Other
Defined Benefit Plan Disclosure [Line Items]
Total	105	103
Private Equity and Other
Defined Benefit Plan Disclosure [Line Items]
Total	388	377
Private Equity and Other | Level 1
Defined Benefit Plan Disclosure [Line Items]
Total	0	0
Private Equity and Other | Level 2
Defined Benefit Plan Disclosure [Line Items]
Total	0	0
Private Equity and Other | Other
Defined Benefit Plan Disclosure [Line Items]
Total	388	377
DTE Electric
Defined Benefit Plan Disclosure [Line Items]
Total	1,087	1,052	$ 1,070
DTE Electric | Level 1
Defined Benefit Plan Disclosure [Line Items]
Total	159	180
DTE Electric | Level 2
Defined Benefit Plan Disclosure [Line Items]
Total	385	348
DTE Electric | Other
Defined Benefit Plan Disclosure [Line Items]
Total	543	524
DTE Electric | Short-term Investments
Defined Benefit Plan Disclosure [Line Items]
Total	24	21
DTE Electric | Short-term Investments | Level 1
Defined Benefit Plan Disclosure [Line Items]
Total	24	21
DTE Electric | Short-term Investments | Level 2
Defined Benefit Plan Disclosure [Line Items]
Total	0	0
DTE Electric | Short-term Investments | Other
Defined Benefit Plan Disclosure [Line Items]
Total	0	0
DTE Electric | Equity Securities, Domestic
Defined Benefit Plan Disclosure [Line Items]
Total	38	42
DTE Electric | Equity Securities, Domestic | Level 1
Defined Benefit Plan Disclosure [Line Items]
Total	0	0
DTE Electric | Equity Securities, Domestic | Level 2
Defined Benefit Plan Disclosure [Line Items]
Total	0	0
DTE Electric | Equity Securities, Domestic | Other
Defined Benefit Plan Disclosure [Line Items]
Total	38	42
DTE Electric | Equity Securities, International
Defined Benefit Plan Disclosure [Line Items]
Total	31	26
DTE Electric | Equity Securities, International | Level 1
Defined Benefit Plan Disclosure [Line Items]
Total	4	4
DTE Electric | Equity Securities, International | Level 2
Defined Benefit Plan Disclosure [Line Items]
Total	0	0
DTE Electric | Equity Securities, International | Other
Defined Benefit Plan Disclosure [Line Items]
Total	27	22
DTE Electric | Fixed Income Securities, Governmental
Defined Benefit Plan Disclosure [Line Items]
Total	134	160
DTE Electric | Fixed Income Securities, Governmental | Level 1
Defined Benefit Plan Disclosure [Line Items]
Total	110	138
DTE Electric | Fixed Income Securities, Governmental | Level 2
Defined Benefit Plan Disclosure [Line Items]
Total	24	22
DTE Electric | Fixed Income Securities, Governmental | Other
Defined Benefit Plan Disclosure [Line Items]
Total	0	0
DTE Electric | Fixed Income Securities, Corporate
Defined Benefit Plan Disclosure [Line Items]
Total	510	465
DTE Electric | Fixed Income Securities, Corporate | Level 1
Defined Benefit Plan Disclosure [Line Items]
Total	0	0
DTE Electric | Fixed Income Securities, Corporate | Level 2
Defined Benefit Plan Disclosure [Line Items]
Total	359	324
DTE Electric | Fixed Income Securities, Corporate | Other
Defined Benefit Plan Disclosure [Line Items]
Total	151	141
DTE Electric | Hedge Funds and Similar Investments
Defined Benefit Plan Disclosure [Line Items]
Total	93	88
DTE Electric | Hedge Funds and Similar Investments | Level 1
Defined Benefit Plan Disclosure [Line Items]
Total	21	17
DTE Electric | Hedge Funds and Similar Investments | Level 2
Defined Benefit Plan Disclosure [Line Items]
Total	2	2
DTE Electric | Hedge Funds and Similar Investments | Other
Defined Benefit Plan Disclosure [Line Items]
Total	70	69
DTE Electric | Private Equity and Other
Defined Benefit Plan Disclosure [Line Items]
Total	257	250
DTE Electric | Private Equity and Other | Level 1
Defined Benefit Plan Disclosure [Line Items]
Total	0	0
DTE Electric | Private Equity and Other | Level 2
Defined Benefit Plan Disclosure [Line Items]
Total	0	0
DTE Electric | Private Equity and Other | Other
Defined Benefit Plan Disclosure [Line Items]
Total	$ 257	$ 250