Fair Value (Reconciliation of Level 3 Assets and Liabilities at Fair Value on a Recurring Basis) (Details) - Recurring - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Roll Forward]
Net Assets (Liabilities) as of beginning of period	$ 9	$ (23)	$ (44)	$ (9)
Transfers into Level 3 from Level 2	0	0	0	0
Transfers from Level 3 into Level 2	0	0	0	(3)
Total gains (losses):
Included in earnings	2	(9)	42	(102)
Recorded in/Change in fair value recorded in Regulatory liabilities	(3)	(8)	3	6
Purchases, issuances, and settlements
Settlements	(36)	(10)	(29)	58
Net Assets (Liabilities) as of end of period	(28)	(50)	(28)	(50)
The amount of total gains (losses) included in Net Income attributed to the change in unrealized gains (losses) related to assets and liabilities held at September 30, 2019 and 2018 and reflected in Operating Revenues — Non-utility operations and Fuel, purchased power, and gas — non-utility in DTE Energy's Consolidated Statements of Operations	(22)	(22)	6	(108)
DTE Electric
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Roll Forward]
Net Assets (Liabilities) as of beginning of period	9	15	6	9
Total gains (losses):
Recorded in/Change in fair value recorded in Regulatory liabilities	(3)	(8)	3	6
Purchases, issuances, and settlements
Settlements	(1)	(1)	(4)	(9)
Net Assets (Liabilities) as of end of period	5	6	5	6
The amount of total gains (losses) included in Regulatory liabilities attributed to the change in unrealized gains (losses) related to assets held at September 30, 2019 and 2018 and reflected in DTE Electric's Consolidated Statements of Financial Position	(1)	(2)	5	6
Natural gas
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Roll Forward]
Net Assets (Liabilities) as of beginning of period	(10)	(25)	(49)	(29)
Transfers into Level 3 from Level 2	0	0	0	0
Transfers from Level 3 into Level 2	0	0	0	(3)
Total gains (losses):
Included in earnings	(35)	(30)	(4)	(128)
Recorded in/Change in fair value recorded in Regulatory liabilities	0	0	0	0
Purchases, issuances, and settlements
Settlements	4	9	12	114
Net Assets (Liabilities) as of end of period	(41)	(46)	(41)	(46)
The amount of total gains (losses) included in Net Income attributed to the change in unrealized gains (losses) related to assets and liabilities held at September 30, 2019 and 2018 and reflected in Operating Revenues — Non-utility operations and Fuel, purchased power, and gas — non-utility in DTE Energy's Consolidated Statements of Operations	(36)	(31)	(20)	(109)
Electricity
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Roll Forward]
Net Assets (Liabilities) as of beginning of period	10	(13)	(2)	12
Transfers into Level 3 from Level 2	0	0	0	0
Transfers from Level 3 into Level 2	0	0	0	0
Total gains (losses):
Included in earnings	37	21	47	25
Recorded in/Change in fair value recorded in Regulatory liabilities	0	0	0	0
Purchases, issuances, and settlements
Settlements	(39)	(18)	(37)	(47)
Net Assets (Liabilities) as of end of period	8	(10)	8	(10)
The amount of total gains (losses) included in Net Income attributed to the change in unrealized gains (losses) related to assets and liabilities held at September 30, 2019 and 2018 and reflected in Operating Revenues — Non-utility operations and Fuel, purchased power, and gas — non-utility in DTE Energy's Consolidated Statements of Operations	15	10	32	4
Other
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Roll Forward]
Net Assets (Liabilities) as of beginning of period	9	15	7	8
Transfers into Level 3 from Level 2	0	0	0	0
Transfers from Level 3 into Level 2	0	0	0	0
Total gains (losses):
Included in earnings	0	0	(1)	1
Recorded in/Change in fair value recorded in Regulatory liabilities	(3)	(8)	3	6
Purchases, issuances, and settlements
Settlements	(1)	(1)	(4)	(9)
Net Assets (Liabilities) as of end of period	5	6	5	6
The amount of total gains (losses) included in Net Income attributed to the change in unrealized gains (losses) related to assets and liabilities held at September 30, 2019 and 2018 and reflected in Operating Revenues — Non-utility operations and Fuel, purchased power, and gas — non-utility in DTE Energy's Consolidated Statements of Operations	$ (1)	$ (1)	$ (6)	$ (3)