Retirement Benefits and Trusteed Assets (Pension Plan - Fair Value Measurements) (Details) - Pension plan - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Defined Benefit Plan Disclosure [Line Items]
Plan assets at fair value	$ 4,012	$ 3,832	$ 3,981
Assets valued at NAV	1,112	1,039
Short-term investments
Defined Benefit Plan Disclosure [Line Items]
Plan assets at fair value	22	23
U.S. Large Capitalization (Cap) Equity Securities
Defined Benefit Plan Disclosure [Line Items]
Plan assets at fair value	880	842
U.S. Small Cap and Mid Cap Equity Securities
Defined Benefit Plan Disclosure [Line Items]
Plan assets at fair value	232	219
Non-U.S. Equity Securities
Defined Benefit Plan Disclosure [Line Items]
Plan assets at fair value	766	761
Assets valued at NAV	269	251
Fixed Income Securities
Defined Benefit Plan Disclosure [Line Items]
Plan assets at fair value	1,090	1,029
Assets valued at NAV	52	50
Hedge Funds and Similar Investments
Defined Benefit Plan Disclosure [Line Items]
Plan assets at fair value	809	768
Assets valued at NAV	578	548
Private Equity and Other
Defined Benefit Plan Disclosure [Line Items]
Plan assets at fair value	213	190
Assets valued at NAV	213	190
Securities lending
Defined Benefit Plan Disclosure [Line Items]
Plan assets at fair value	(78)	(154)
Securities lending collateral
Defined Benefit Plan Disclosure [Line Items]
Plan assets at fair value	78	154
Level 1
Defined Benefit Plan Disclosure [Line Items]
Plan assets at fair value	1,815	1,819
Level 1 | Short-term investments
Defined Benefit Plan Disclosure [Line Items]
Plan assets at fair value	0	23
Level 1 | U.S. Large Capitalization (Cap) Equity Securities
Defined Benefit Plan Disclosure [Line Items]
Plan assets at fair value	875	842
Level 1 | U.S. Small Cap and Mid Cap Equity Securities
Defined Benefit Plan Disclosure [Line Items]
Plan assets at fair value	229	219
Level 1 | Non-U.S. Equity Securities
Defined Benefit Plan Disclosure [Line Items]
Plan assets at fair value	479	510
Level 1 | Fixed Income Securities
Defined Benefit Plan Disclosure [Line Items]
Plan assets at fair value	1	5
Level 1 | Hedge Funds and Similar Investments
Defined Benefit Plan Disclosure [Line Items]
Plan assets at fair value	231	220
Level 1 | Private Equity and Other
Defined Benefit Plan Disclosure [Line Items]
Plan assets at fair value	0	0
Level 1 | Securities lending
Defined Benefit Plan Disclosure [Line Items]
Plan assets at fair value	(53)	(129)
Level 1 | Securities lending collateral
Defined Benefit Plan Disclosure [Line Items]
Plan assets at fair value	53	129
Level 2
Defined Benefit Plan Disclosure [Line Items]
Plan assets at fair value	1,085	974
Level 2 | Short-term investments
Defined Benefit Plan Disclosure [Line Items]
Plan assets at fair value	22	0
Level 2 | U.S. Large Capitalization (Cap) Equity Securities
Defined Benefit Plan Disclosure [Line Items]
Plan assets at fair value	5	0
Level 2 | U.S. Small Cap and Mid Cap Equity Securities
Defined Benefit Plan Disclosure [Line Items]
Plan assets at fair value	3	0
Level 2 | Non-U.S. Equity Securities
Defined Benefit Plan Disclosure [Line Items]
Plan assets at fair value	18	0
Level 2 | Fixed Income Securities
Defined Benefit Plan Disclosure [Line Items]
Plan assets at fair value	1,037	974
Level 2 | Hedge Funds and Similar Investments
Defined Benefit Plan Disclosure [Line Items]
Plan assets at fair value	0	0
Level 2 | Private Equity and Other
Defined Benefit Plan Disclosure [Line Items]
Plan assets at fair value	0	0
Level 2 | Securities lending
Defined Benefit Plan Disclosure [Line Items]
Plan assets at fair value	(25)	(25)
Level 2 | Securities lending collateral
Defined Benefit Plan Disclosure [Line Items]
Plan assets at fair value	25	25
DTE Electric
Defined Benefit Plan Disclosure [Line Items]
Plan assets at fair value	2,837	2,709	$ 2,812
Assets valued at NAV	760	709
DTE Electric | Short-term investments
Defined Benefit Plan Disclosure [Line Items]
Plan assets at fair value	16	16
DTE Electric | U.S. Large Capitalization (Cap) Equity Securities
Defined Benefit Plan Disclosure [Line Items]
Plan assets at fair value	626	599
DTE Electric | U.S. Small Cap and Mid Cap Equity Securities
Defined Benefit Plan Disclosure [Line Items]
Plan assets at fair value	167	157
DTE Electric | Non-U.S. Equity Securities
Defined Benefit Plan Disclosure [Line Items]
Plan assets at fair value	548	545
Assets valued at NAV	191	178
DTE Electric | Fixed Income Securities
Defined Benefit Plan Disclosure [Line Items]
Plan assets at fair value	745	703
DTE Electric | Hedge Funds and Similar Investments
Defined Benefit Plan Disclosure [Line Items]
Plan assets at fair value	582	552
Assets valued at NAV	416	394
DTE Electric | Private Equity and Other
Defined Benefit Plan Disclosure [Line Items]
Plan assets at fair value	153	137
Assets valued at NAV	153	137
DTE Electric | Securities lending
Defined Benefit Plan Disclosure [Line Items]
Plan assets at fair value	(56)	(111)
DTE Electric | Securities lending collateral
Defined Benefit Plan Disclosure [Line Items]
Plan assets at fair value	56	111
DTE Electric | Level 1
Defined Benefit Plan Disclosure [Line Items]
Plan assets at fair value	1,297	1,301
DTE Electric | Level 1 | Short-term investments
Defined Benefit Plan Disclosure [Line Items]
Plan assets at fair value	0	16
DTE Electric | Level 1 | U.S. Large Capitalization (Cap) Equity Securities
Defined Benefit Plan Disclosure [Line Items]
Plan assets at fair value	622	599
DTE Electric | Level 1 | U.S. Small Cap and Mid Cap Equity Securities
Defined Benefit Plan Disclosure [Line Items]
Plan assets at fair value	165	157
DTE Electric | Level 1 | Non-U.S. Equity Securities
Defined Benefit Plan Disclosure [Line Items]
Plan assets at fair value	344	367
DTE Electric | Level 1 | Fixed Income Securities
Defined Benefit Plan Disclosure [Line Items]
Plan assets at fair value	0	4
DTE Electric | Level 1 | Hedge Funds and Similar Investments
Defined Benefit Plan Disclosure [Line Items]
Plan assets at fair value	166	158
DTE Electric | Level 1 | Private Equity and Other
Defined Benefit Plan Disclosure [Line Items]
Plan assets at fair value	0	0
DTE Electric | Level 1 | Securities lending
Defined Benefit Plan Disclosure [Line Items]
Plan assets at fair value	(38)	(93)
DTE Electric | Level 1 | Securities lending collateral
Defined Benefit Plan Disclosure [Line Items]
Plan assets at fair value	38	93
DTE Electric | Level 2
Defined Benefit Plan Disclosure [Line Items]
Plan assets at fair value	780	699
DTE Electric | Level 2 | Short-term investments
Defined Benefit Plan Disclosure [Line Items]
Plan assets at fair value	16	0
DTE Electric | Level 2 | U.S. Large Capitalization (Cap) Equity Securities
Defined Benefit Plan Disclosure [Line Items]
Plan assets at fair value	4	0
DTE Electric | Level 2 | U.S. Small Cap and Mid Cap Equity Securities
Defined Benefit Plan Disclosure [Line Items]
Plan assets at fair value	2	0
DTE Electric | Level 2 | Non-U.S. Equity Securities
Defined Benefit Plan Disclosure [Line Items]
Plan assets at fair value	13	0
DTE Electric | Level 2 | Fixed Income Securities
Defined Benefit Plan Disclosure [Line Items]
Plan assets at fair value	745	699
DTE Electric | Level 2 | Hedge Funds and Similar Investments
Defined Benefit Plan Disclosure [Line Items]
Plan assets at fair value	0	0
DTE Electric | Level 2 | Private Equity and Other
Defined Benefit Plan Disclosure [Line Items]
Plan assets at fair value	0	0
DTE Electric | Level 2 | Securities lending
Defined Benefit Plan Disclosure [Line Items]
Plan assets at fair value	(18)	(18)
DTE Electric | Level 2 | Securities lending collateral
Defined Benefit Plan Disclosure [Line Items]
Plan assets at fair value	$ 18	$ 18