XML 88 R57.htm IDEA: XBRL DOCUMENT v3.3.1.900
Contingencies And Commitments (Contingencies And Commitments) (Details)
$ in Millions
9 Months Ended 12 Months Ended
Sep. 30, 2015
USD ($)
Dec. 31, 2015
USD ($)
site
lawsuit
Dec. 31, 2014
USD ($)
Loss Contingencies [Line Items]      
Increase due to change in estimate   $ 74
Regulatory assets   1,840 $ 1,956
Consumers Energy Company [Member]      
Loss Contingencies [Line Items]      
Increase due to change in estimate   74
Regulatory assets   $ 1,840 $ 1,956
Bay Harbor [Member]      
Loss Contingencies [Line Items]      
Environmental remediation permit renewal term   5 years  
Demand for payment by USEPA   $ 8  
Accrual for environmental loss contingencies   $ 58  
Discounted projected costs rate   4.34%  
Remaining undiscounted obligation amount   $ 74  
Accrual for environmental loss contingencies, inflation rate   1.00%  
CERCLA Liability [Member] | Consumers Energy Company [Member]      
Loss Contingencies [Line Items]      
Accrual for environmental loss contingencies   $ 3  
Remediation and other response activity costs, minimum   3  
Remediation and other response activity costs, maximum   8  
Manufactured Gas Plant [Member] | Consumers Energy Company [Member]      
Loss Contingencies [Line Items]      
Accrual for environmental loss contingencies   $ 114  
Discounted projected costs rate   2.57%  
Remaining undiscounted obligation amount   $ 129  
Number of former MGPs | site   23  
Regulatory assets   $ 146  
Authorized recovery, collection period   10 years  
Accrual for environmental loss contingencies, inflation rate   2.50%  
Coal Ash Disposal [Member] | Consumers Energy Company [Member]      
Loss Contingencies [Line Items]      
Increase due to change in estimate $ 68    
Electric Utility [Member] | NREPA [Member] | Consumers Energy Company [Member]      
Loss Contingencies [Line Items]      
Accrual for environmental loss contingencies   $ 3  
Remediation and other response activity costs, minimum   3  
Remediation and other response activity costs, maximum   5  
Gas Utility [Member] | NREPA [Member] | Consumers Energy Company [Member]      
Loss Contingencies [Line Items]      
Accrual for environmental loss contingencies   1  
Remediation and other response activity costs, maximum   3  
Equatorial Guinea Tax Claim [Member]      
Loss Contingencies [Line Items]      
Foreign government tax claim on sale   $ 152  
Class Action Lawsuits [Member]      
Loss Contingencies [Line Items]      
Number of lawsuits | lawsuit   4  
Individual Lawsuits [Member]      
Loss Contingencies [Line Items]      
Number of lawsuits | lawsuit   1