Fair Value (Reconciliation of Level 3 Assets and Liabilities at Fair Value on a Recurring Basis) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 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	$ (12)	$ (43)	$ 24	$ (36)
Transfers into Level 3	0	0	0	0
Transfers out of Level 3	0	0	0	0
Total gains (losses):
Included in earnings	14	(39)	(13)	(19)
Recorded in regulatory assets/liabilities	13	7	11	11
Purchases, issuances and settlements:
Purchases	1	0	2	0
Issuances	0	(1)	0	(2)
Settlements	(20)	36	(28)	6
Net Assets (Liabilities) as of June 30	(4)	(40)	(4)	(40)
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 June 30, 2015 and 2014 and reflected in Operating revenues and Fuel, purchased power and gas in DTE Energy's Consolidated Statements of Operations	(4)	(10)	(102)	(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	1	1	3	3
Total gains (losses):
Recorded in regulatory assets/liabilities	13	7	11	11
Purchases, issuances and settlements:
Settlements	(9)	(1)	(9)	(7)
Net Assets (Liabilities) as of June 30	5	7	5	7
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 June 30, 2015 and 2014 and reflected in DTE Electric's Consolidated Statements of Financial Position	5	7	5	7
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	0	(10)	30	(52)
Transfers into Level 3	0	0	0	0
Transfers out of Level 3	0	0	0	0
Total gains (losses):
Included in earnings	(5)	(16)	(35)	(38)
Recorded in regulatory assets/liabilities	0	0	0	0
Purchases, issuances and settlements:
Purchases	0	0	0	0
Issuances	0	0	0	0
Settlements	(3)	6	(3)	70
Net Assets (Liabilities) as of June 30	(8)	(20)	(8)	(20)
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 June 30, 2015 and 2014 and reflected in Operating revenues and Fuel, purchased power and gas in DTE Energy's Consolidated Statements of Operations	(20)	(11)	(112)	(11)
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	(7)	(34)	(5)	13
Transfers into Level 3	0	0	0	0
Transfers out of Level 3	0	0	0	0
Total gains (losses):
Included in earnings	18	(22)	24	20
Recorded in regulatory assets/liabilities	0	0	0	0
Purchases, issuances and settlements:
Purchases	1	0	2	0
Issuances	0	(1)	0	(2)
Settlements	(9)	30	(18)	(58)
Net Assets (Liabilities) as of June 30	3	(27)	3	(27)
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 June 30, 2015 and 2014 and reflected in Operating revenues and Fuel, purchased power and gas in DTE Energy's Consolidated Statements of Operations	15	1	11	(19)
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	(5)	1	(1)	3
Transfers into Level 3	0	0	0	0
Transfers out of Level 3	0	0	0	0
Total gains (losses):
Included in earnings	1	(1)	(2)	(1)
Recorded in regulatory assets/liabilities	13	7	11	11
Purchases, issuances and settlements:
Purchases	0	0	0	0
Issuances	0	0	0	0
Settlements	(8)	0	(7)	(6)
Net Assets (Liabilities) as of June 30	1	7	1	7
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 June 30, 2015 and 2014 and reflected in Operating revenues and Fuel, purchased power and gas in DTE Energy's Consolidated Statements of Operations	$ 1	$ 0	$ (1)	$ 0