Fair Value (Fair Value of Nuclear Decommissioning Trust Fund Assets) (Details) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019
Debt Securities, Available-for-sale [Line Items]
Nuclear decommissioning trust funds	$ 1,855	$ 1,661
DTE Electric
Debt Securities, Available-for-sale [Line Items]
Nuclear decommissioning trust funds	1,855	1,661
DTE Electric \| Nuclear decommissioning trusts
Debt Securities, Available-for-sale [Line Items]
Nuclear decommissioning trust funds	1,855	1,661
DTE Electric \| Nuclear decommissioning trusts \| Fermi 2
Debt Securities, Available-for-sale [Line Items]
Nuclear decommissioning trust funds	1,841	1,650
DTE Electric \| Nuclear decommissioning trusts \| Fermi 1
Debt Securities, Available-for-sale [Line Items]
Nuclear decommissioning trust funds	3	3
DTE Electric \| Nuclear decommissioning trusts \| Low-level radioactive waste
Debt Securities, Available-for-sale [Line Items]
Nuclear decommissioning trust funds	$ 11	$ 8

Decommission fund to pay for the costs of decontaminating and decommissioning of facilities through collection of revenues derived from utility assessments and government appropriations. Decommission fund investment for the process whereby a power station, at the end of its economic life, is taken permanently out of service and its site made available for other purposes. In the case of a nuclear station this comprises three different states of clearance. Immediately after the final closure, radioactive material such as nuclear fuel and operational waste is removed and the buildings surrounding the reactor shield are dismantled and finally the reactor itself is dismantled.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.12)
-URI http://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682

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Balance Type:	debit
Period Type:	instant