Fair Value (Reconciliation of Level 3 Assets and Liabilities at Fair Value on a Recurring Basis) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Fair value reconciliation of Level 3 assets and liabilities measured at fair value on a recurring basis
Net Assets (Liabilities) as of beginning of period	$ (4)	$ (40)	$ 24	$ (36)
Transfers into Level 3 from Level 2	0	1	0	0
Transfers from Level 3 into Level 2	0	(4)	0	2
Total gains (losses):
Included in earnings	39	10	26	(21)
Recorded in regulatory assets/liabilities	3	(3)	14	9
Purchases, issuances, and settlements:
Purchases	0	0	2	1
Issuances	0	0	0	(2)
Settlements	(15)	(6)	(43)	5
Net Assets (Liabilities) as of end of period	23	(42)	23	(42)
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, 2015 and 2014 and reflected in Operating revenues and Fuel, purchased power and gas in DTE Energy's Consolidated Statements of Operations	12	6	(90)	(30)
DTE Electric
Fair value reconciliation of Level 3 assets and liabilities measured at fair value on a recurring basis
Net Assets (Liabilities) as of beginning of period	5	7	3	3
Total gains (losses):
Recorded in regulatory assets/liabilities	3	(3)	14	9
Purchases, issuances, and settlements:
Settlements	(3)	0	(12)	(8)
Net Assets (Liabilities) as of end of period	5	4	5	4
The amount of total gains (losses) included in Regulatory assets and liabilities attributed to the change in unrealized gains (losses) related to assets and liabilities held at September 30, 2015 and 2014 and reflected in DTE Electric's Consolidated Statements of Financial Position	1	(1)	5	4
Natural Gas
Fair value reconciliation of Level 3 assets and liabilities measured at fair value on a recurring basis
Net Assets (Liabilities) as of beginning of period	(8)	(20)	30	(52)
Transfers into Level 3 from Level 2	0	1	0	0
Transfers from Level 3 into Level 2	0	(4)	0	2
Total gains (losses):
Included in earnings	24	(2)	(11)	(45)
Recorded in regulatory assets/liabilities	0	0	0	0
Purchases, issuances, and settlements:
Purchases	0	0	0	0
Issuances	0	0	0	0
Settlements	5	(3)	2	67
Net Assets (Liabilities) as of end of period	21	(28)	21	(28)
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, 2015 and 2014 and reflected in Operating revenues and Fuel, purchased power and gas in DTE Energy's Consolidated Statements of Operations	18	(7)	(94)	(23)
Electricity
Fair value reconciliation of Level 3 assets and liabilities measured at fair value on a recurring basis
Net Assets (Liabilities) as of beginning of period	3	(27)	(5)	13
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	18	13	42	26
Recorded in regulatory assets/liabilities	0	0	0	0
Purchases, issuances, and settlements:
Purchases	0	0	2	1
Issuances	0	0	0	(2)
Settlements	(18)	(3)	(36)	(55)
Net Assets (Liabilities) as of end of period	3	(17)	3	(17)
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, 2015 and 2014 and reflected in Operating revenues and Fuel, purchased power and gas in DTE Energy's Consolidated Statements of Operations	(3)	14	8	(6)
Other
Fair value reconciliation of Level 3 assets and liabilities measured at fair value on a recurring basis
Net Assets (Liabilities) as of beginning of period	1	7	(1)	3
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	(3)	(1)	(5)	(2)
Recorded in regulatory assets/liabilities	3	(3)	14	9
Purchases, issuances, and settlements:
Purchases	0	0	0	0
Issuances	0	0	0	0
Settlements	(2)	0	(9)	(7)
Net Assets (Liabilities) as of end of period	(1)	3	(1)	3
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, 2015 and 2014 and reflected in Operating revenues and Fuel, purchased power and gas in DTE Energy's Consolidated Statements of Operations	$ (3)	$ (1)	$ (4)	$ (1)