Long-Term Debt Long-Term Debt (Debt Issuances) (Details) (USD $) In Millions, unless otherwise specified	Jun. 30, 2014	May 31, 2014 DTE Energy [Member] Senior Notes [Member]	May 31, 2014 DTE Energy [Member] Ten Years [Member] Senior Notes [Member]	Jun. 30, 2014 Electric [Member] Twelve Years [Member] Mortgages [Member]	Jun. 30, 2014 Electric [Member] Thirty Years [Member] Mortgages [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage		7.625%	3.50%	3.77%	4.60%
Debt Instrument, Face Amount	$ 600		$ 350	$ 100	$ 150