Retirement Benefits and Trusteed Assets (OPEB - Accumulated Postretirement Obligations in Excess of Plan Assets) (Details) - Other postretirement benefit plan - USD ($) $ in Millions	Dec. 31, 2022	Dec. 31, 2021
Defined Benefit Plan Disclosure [Line Items]
Accumulated postretirement benefit obligation	$ 625	$ 822
Fair value of plan assets	338	463
Accumulated postretirement benefit obligation in excess of plan assets	287	359
DTE Electric
Defined Benefit Plan Disclosure [Line Items]
Accumulated postretirement benefit obligation	591	775
Fair value of plan assets	316	435
Accumulated postretirement benefit obligation in excess of plan assets	$ 275	$ 340