Contingencies And Commitments (Contingencies And Commitments) (Details) (USD $) In Millions, unless otherwise specified						6 Months Ended		6 Months Ended				1 Months Ended
	Jun. 30, 2014	Dec. 31, 2013	Oct. 31, 2010	Jun. 30, 2014 Consumers Energy Company [Member]	Dec. 31, 2013 Consumers Energy Company [Member]	Jun. 30, 2014 Bay Harbor [Member]	Jun. 30, 2014 CERCLA Liability [Member] Consumers Energy Company [Member]	Jun. 30, 2014 Manufactured Gas Plant [Member] Consumers Energy Company [Member] item	Jun. 30, 2014 Electric Utility [Member] Consumers Energy Company [Member] item	Jun. 30, 2014 Electric Utility [Member] NREPA [Member] Consumers Energy Company [Member]	Jun. 30, 2014 Gas Utility [Member] NREPA [Member] Consumers Energy Company [Member]	Jul. 31, 2011 DOE Settlement [Member] Consumers Energy Company [Member]
Regulatory Matters [Line Items]
Environmental remediation permit renewal term						5 years
Demand for payment by USEPA			$ 7
Cumulative environmental charge						230
Accrual for environmental loss contingencies						50	3	118		4	1
Discounted projected costs rate						4.34%		2.57%
Remaining undiscounted obligation amount						68		134
Foreign government tax claim on sale	142
Remediation and other response activity costs, minimum							3			4
Remediation and other response activity costs. maximum							9			6	3
Number of boilers alleged to exceed emission limits									14
Alleged number of facilities in violation									3
Number of projects affected by alleged violations									10
Litigation settlement, gross												120
Number of former MGPs								23
Regulatory assets	$ 1,463	$ 1,530		$ 1,463	$ 1,530			$ 148
Authorized recovery, collection period								10 years
Accrual for environmental loss contingencies, inflation rate						1.00%		2.50%