Fair Value (Reconciliation of Level 3 Assets and Liabilities at Fair Value on a Recurring Basis) (Details) - Recurring - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Roll Forward]
Net Assets (Liabilities) as of January 1	$ (88)	$ (4)
Transfers into Level 3 from Level 2	0	0
Transfers from Level 3 into Level 2	0	0
Total gains (losses)
Included in earnings	82	(160)
Recorded in Regulatory liabilities	25	6
Purchases, issuances, and settlements:
Purchases	0	1
Settlements	(28)	69
Net Assets (Liabilities) as of December 31	(9)	(88)
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 December 31, 2017 and 2016 and reflected in Operating Revenues — Non-utility operations and Fuel, purchased power, and gas — non-utility in DTE Energy's Consolidated Statements of Operations	21	(157)
Natural Gas
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Roll Forward]
Net Assets (Liabilities) as of January 1	(96)	(5)
Transfers into Level 3 from Level 2	0	0
Transfers from Level 3 into Level 2	0	0
Total gains (losses)
Included in earnings	(29)	(159)
Recorded in Regulatory liabilities	0	0
Purchases, issuances, and settlements:
Purchases	0	0
Settlements	96	68
Net Assets (Liabilities) as of December 31	(29)	(96)
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 December 31, 2017 and 2016 and reflected in Operating Revenues — Non-utility operations and Fuel, purchased power, and gas — non-utility in DTE Energy's Consolidated Statements of Operations	(30)	(166)
Electricity
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Roll Forward]
Net Assets (Liabilities) as of January 1	9	6
Transfers into Level 3 from Level 2	0	0
Transfers from Level 3 into Level 2	0	0
Total gains (losses)
Included in earnings	109	(2)
Recorded in Regulatory liabilities	0	0
Purchases, issuances, and settlements:
Purchases	0	1
Settlements	(106)	4
Net Assets (Liabilities) as of December 31	12	9
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 December 31, 2017 and 2016 and reflected in Operating Revenues — Non-utility operations and Fuel, purchased power, and gas — non-utility in DTE Energy's Consolidated Statements of Operations	50	7
Other
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Roll Forward]
Net Assets (Liabilities) as of January 1	(1)	(5)
Transfers into Level 3 from Level 2	0	0
Transfers from Level 3 into Level 2	0	0
Total gains (losses)
Included in earnings	2	1
Recorded in Regulatory liabilities	25	6
Purchases, issuances, and settlements:
Purchases	0	0
Settlements	(18)	(3)
Net Assets (Liabilities) as of December 31	8	(1)
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 December 31, 2017 and 2016 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	2
DTE Electric
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Roll Forward]
Net Assets (Liabilities) as of January 1	2	3
Total gains (losses)
Recorded in Regulatory liabilities	25	6
Purchases, issuances, and settlements:
Settlements	(18)	(7)
Net Assets (Liabilities) as of December 31	9	2
The amount of total gains (losses) included in Regulatory liabilities attributed to the change in unrealized gains (losses) related to assets and liabilities held at December 31, 2017 and 2016 and reflected in DTE Electric's Consolidated Statements of Financial Position	$ 9	$ 2