Retirement Benefits and Trusteed Assets (OPEB - Fair Value Measurements) (Details) - Other postretirement benefit plan - USD ($) $ in Millions	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Defined Benefit Plan Disclosure [Line Items]
Plan assets at fair value	$ 2,021	$ 1,960	$ 1,819
Level 1
Defined Benefit Plan Disclosure [Line Items]
Plan assets at fair value	494	196
Level 2
Defined Benefit Plan Disclosure [Line Items]
Plan assets at fair value	413	539
Other
Defined Benefit Plan Disclosure [Line Items]
Plan assets at fair value	1,114	1,225
Short-term Investments
Defined Benefit Plan Disclosure [Line Items]
Plan assets at fair value	39	21
Short-term Investments | Level 1
Defined Benefit Plan Disclosure [Line Items]
Plan assets at fair value	39	21
Short-term Investments | Level 2
Defined Benefit Plan Disclosure [Line Items]
Plan assets at fair value	0	0
Short-term Investments | Other
Defined Benefit Plan Disclosure [Line Items]
Plan assets at fair value	0	0
Equity Securities, Domestic
Defined Benefit Plan Disclosure [Line Items]
Plan assets at fair value	226	251
Equity Securities, Domestic | Level 1
Defined Benefit Plan Disclosure [Line Items]
Plan assets at fair value	27	51
Equity Securities, Domestic | Level 2
Defined Benefit Plan Disclosure [Line Items]
Plan assets at fair value	0	0
Equity Securities, Domestic | Other
Defined Benefit Plan Disclosure [Line Items]
Plan assets at fair value	199	200
Equity Securities, International
Defined Benefit Plan Disclosure [Line Items]
Plan assets at fair value	168	201
Equity Securities, International | Level 1
Defined Benefit Plan Disclosure [Line Items]
Plan assets at fair value	27	23
Equity Securities, International | Level 2
Defined Benefit Plan Disclosure [Line Items]
Plan assets at fair value	0	0
Equity Securities, International | Other
Defined Benefit Plan Disclosure [Line Items]
Plan assets at fair value	141	178
Fixed Income Securities, Governmental
Defined Benefit Plan Disclosure [Line Items]
Plan assets at fair value	375	85
Fixed Income Securities, Governmental | Level 1
Defined Benefit Plan Disclosure [Line Items]
Plan assets at fair value	343	40
Fixed Income Securities, Governmental | Level 2
Defined Benefit Plan Disclosure [Line Items]
Plan assets at fair value	32	45
Fixed Income Securities, Governmental | Other
Defined Benefit Plan Disclosure [Line Items]
Plan assets at fair value	0	0
Fixed Income Securities, Corporate
Defined Benefit Plan Disclosure [Line Items]
Plan assets at fair value	626	856
Fixed Income Securities, Corporate | Level 1
Defined Benefit Plan Disclosure [Line Items]
Plan assets at fair value	0	0
Fixed Income Securities, Corporate | Level 2
Defined Benefit Plan Disclosure [Line Items]
Plan assets at fair value	355	477
Fixed Income Securities, Corporate | Other
Defined Benefit Plan Disclosure [Line Items]
Plan assets at fair value	271	379
Hedge Funds and Similar Investments
Defined Benefit Plan Disclosure [Line Items]
Plan assets at fair value	204	202
Hedge Funds and Similar Investments | Level 1
Defined Benefit Plan Disclosure [Line Items]
Plan assets at fair value	58	61
Hedge Funds and Similar Investments | Level 2
Defined Benefit Plan Disclosure [Line Items]
Plan assets at fair value	26	17
Hedge Funds and Similar Investments | Other
Defined Benefit Plan Disclosure [Line Items]
Plan assets at fair value	120	124
Private Equity and Other
Defined Benefit Plan Disclosure [Line Items]
Plan assets at fair value	383	344
Private Equity and Other | Level 1
Defined Benefit Plan Disclosure [Line Items]
Plan assets at fair value	0	0
Private Equity and Other | Level 2
Defined Benefit Plan Disclosure [Line Items]
Plan assets at fair value	0	0
Private Equity and Other | Other
Defined Benefit Plan Disclosure [Line Items]
Plan assets at fair value	383	344
DTE Electric
Defined Benefit Plan Disclosure [Line Items]
Plan assets at fair value	1,355	1,320	$ 1,236
DTE Electric | Level 1
Defined Benefit Plan Disclosure [Line Items]
Plan assets at fair value	331	128
DTE Electric | Level 2
Defined Benefit Plan Disclosure [Line Items]
Plan assets at fair value	273	363
DTE Electric | Other
Defined Benefit Plan Disclosure [Line Items]
Plan assets at fair value	751	829
DTE Electric | Short-term Investments
Defined Benefit Plan Disclosure [Line Items]
Plan assets at fair value	26	14
DTE Electric | Short-term Investments | Level 1
Defined Benefit Plan Disclosure [Line Items]
Plan assets at fair value	26	14
DTE Electric | Short-term Investments | Level 2
Defined Benefit Plan Disclosure [Line Items]
Plan assets at fair value	0	0
DTE Electric | Short-term Investments | Other
Defined Benefit Plan Disclosure [Line Items]
Plan assets at fair value	0	0
DTE Electric | Equity Securities, Domestic
Defined Benefit Plan Disclosure [Line Items]
Plan assets at fair value	150	164
DTE Electric | Equity Securities, Domestic | Level 1
Defined Benefit Plan Disclosure [Line Items]
Plan assets at fair value	18	33
DTE Electric | Equity Securities, Domestic | Level 2
Defined Benefit Plan Disclosure [Line Items]
Plan assets at fair value	0	0
DTE Electric | Equity Securities, Domestic | Other
Defined Benefit Plan Disclosure [Line Items]
Plan assets at fair value	132	131
DTE Electric | Equity Securities, International
Defined Benefit Plan Disclosure [Line Items]
Plan assets at fair value	111	133
DTE Electric | Equity Securities, International | Level 1
Defined Benefit Plan Disclosure [Line Items]
Plan assets at fair value	18	16
DTE Electric | Equity Securities, International | Level 2
Defined Benefit Plan Disclosure [Line Items]
Plan assets at fair value	0	0
DTE Electric | Equity Securities, International | Other
Defined Benefit Plan Disclosure [Line Items]
Plan assets at fair value	93	117
DTE Electric | Fixed Income Securities, Governmental
Defined Benefit Plan Disclosure [Line Items]
Plan assets at fair value	251	55
DTE Electric | Fixed Income Securities, Governmental | Level 1
Defined Benefit Plan Disclosure [Line Items]
Plan assets at fair value	230	24
DTE Electric | Fixed Income Securities, Governmental | Level 2
Defined Benefit Plan Disclosure [Line Items]
Plan assets at fair value	21	31
DTE Electric | Fixed Income Securities, Governmental | Other
Defined Benefit Plan Disclosure [Line Items]
Plan assets at fair value	0	0
DTE Electric | Fixed Income Securities, Corporate
Defined Benefit Plan Disclosure [Line Items]
Plan assets at fair value	422	584
DTE Electric | Fixed Income Securities, Corporate | Level 1
Defined Benefit Plan Disclosure [Line Items]
Plan assets at fair value	0	0
DTE Electric | Fixed Income Securities, Corporate | Level 2
Defined Benefit Plan Disclosure [Line Items]
Plan assets at fair value	235	321
DTE Electric | Fixed Income Securities, Corporate | Other
Defined Benefit Plan Disclosure [Line Items]
Plan assets at fair value	187	263
DTE Electric | Hedge Funds and Similar Investments
Defined Benefit Plan Disclosure [Line Items]
Plan assets at fair value	137	135
DTE Electric | Hedge Funds and Similar Investments | Level 1
Defined Benefit Plan Disclosure [Line Items]
Plan assets at fair value	39	41
DTE Electric | Hedge Funds and Similar Investments | Level 2
Defined Benefit Plan Disclosure [Line Items]
Plan assets at fair value	17	11
DTE Electric | Hedge Funds and Similar Investments | Other
Defined Benefit Plan Disclosure [Line Items]
Plan assets at fair value	81	83
DTE Electric | Private Equity and Other
Defined Benefit Plan Disclosure [Line Items]
Plan assets at fair value	258	235
DTE Electric | Private Equity and Other | Level 1
Defined Benefit Plan Disclosure [Line Items]
Plan assets at fair value	0	0
DTE Electric | Private Equity and Other | Level 2
Defined Benefit Plan Disclosure [Line Items]
Plan assets at fair value	0	0
DTE Electric | Private Equity and Other | Other
Defined Benefit Plan Disclosure [Line Items]
Plan assets at fair value	$ 258	$ 235