Fair Value Measurements (Tables)
9 Months Ended12 Months Ended
Sep. 30, 2011
Sep. 30, 2010
Dec. 31, 2010
Assets and Liabilities Measured at Fair Value on a Recurring Basis
In Millions  
    Total     Level 1     Level 2     Level 3  
 
CMS Energy, including Consumers
                                
Assets
                                
Cash equivalents
   $ 512     $ 512     $ —     $ —  
Restricted cash equivalents
     14       14       —       —  
Nonqualified deferred compensation plan assets
     4       4       —       —  
SERP
                                
Cash equivalents
     1       1       —       —  
Mutual fund
     87       87       —       —  
State and municipal bonds
     26       —       26       —  
Derivative instruments
                                
Commodity contracts1
     2       —       —       2  
 
Total2
   $ 646     $ 618     $ 26     $ 2  
 
Liabilities
                                
Nonqualified deferred compensation plan liabilities
   $ 4     $ 4     $ —     $ —  
Derivative instruments
                                
Commodity contracts3
     3       —       —       3  
 
Total4
   $ 7     $ 4     $ —     $ 3  
 
Consumers
                                
Assets
                                
Cash equivalents
   $ 282     $ 282     $ —     $ —  
Restricted cash equivalents
     13       13       —       —  
CMS Energy common stock
     31       31       —       —  
Nonqualified deferred compensation plan assets
     3       3       —       —  
SERP
                                
Cash equivalents
     1       1       —       —  
Mutual fund
     57       57       —       —  
State and municipal bonds
     17       —       17       —  
Derivative instruments
                                
Commodity contracts
     2       —       —       2  
 
Total5
   $ 406     $ 387     $ 17     $ 2  
 
Liabilities
                                
Nonqualified deferred compensation plan liabilities
   $ 3     $ 3     $ —     $ —  
 
Total
   $ 3     $ 3     $ —     $ —  
 
1   This amount is gross and excludes the impact of offsetting derivative assets and liabilities under master netting arrangements, which was less than $1 million at September 30, 2011.
2   At September 30, 2011, CMS Energy's assets classified as Level 3 represented less than one percent of CMS Energy's total assets measured at fair value.
3   This amount is gross and excludes the impact of offsetting derivative assets and liabilities under master netting arrangements and offsetting cash margin deposits paid by CMS ERM to other parties, which was less than $1 million at September 30, 2011.
4   At September 30, 2011, CMS Energy's liabilities classified as Level 3 represented 43 percent of CMS Energy's total liabilities measured at fair value. The Level 3 liabilities consisted primarily of an electricity sales agreement held by CMS ERM.
5   At September 30, 2011, Consumers' assets classified as Level 3 represented less than one percent of Consumers' total assets measured at fair value.
 
                               
In Millions  
    Total     Level 1     Level 2     Level 3  
 
CMS Energy, including Consumers
                                
Assets
                                
Cash equivalents
   $ 183     $ 183     $ —     $ —  
Restricted cash equivalents
     6       6       —       —  
Nonqualified deferred compensation plan assets
     6       6       —       —  
SERP
                                
Cash equivalents
     1       1       —       —  
Mutual fund
     62       62       —       —  
State and municipal bonds
     28       —       28       —  
Derivative instruments
                                
Commodity contracts1
     1       —       —       1  
 
Total2
   $ 287     $ 258     $ 28     $ 1  
 
Liabilities
                                
Nonqualified deferred compensation plan liabilities
   $ 6     $ 6     $ —     $ —  
Derivative instruments
                                
Commodity contracts3
     4       —       —       4  
 
Total4
   $ 10     $ 6     $ —     $ 4  
 
Consumers
                                
Assets
                                
Cash equivalents
   $ 19     $ 19     $ —     $ —  
Restricted cash equivalents
     6       6       —       —  
CMS Energy common stock
     34       34       —       —  
Nonqualified deferred compensation plan assets
     4       4       —       —  
SERP
                                
Cash equivalents
     1       1       —       —  
Mutual fund
     39       39       —       —  
State and municipal bonds
     17       —       17       —  
Derivative instruments
                                
Commodity contracts
     1       —       —       1  
 
Total5
   $ 121     $ 103     $ 17     $ 1  
 
Liabilities
                                
Nonqualified deferred compensation plan liabilities
   $ 4     $ 4     $ —     $ —  
 
Total
   $ 4     $ 4     $ —     $ —  
 
1   This amount is gross and excludes the impact of offsetting derivative assets and liabilities under master netting arrangements, which was less than $1 million at December 31, 2010.
2   At December 31, 2010, CMS Energy's assets classified as Level 3 represented less than one percent of CMS Energy's total assets measured at fair value.
 
3   This amount is gross and excludes the impact of offsetting derivative assets and liabilities under master netting arrangements and offsetting cash margin deposits paid by CMS ERM to other parties, which was less than $1 million at December 31, 2010.
 
4   At December 31, 2010, CMS Energy's liabilities classified as Level 3 represented 40 percent of CMS Energy's total liabilities measured at fair value. The Level 3 liabilities consisted primarily of an electricity sales agreement held by CMS ERM.
 
5   At December 31, 2010, Consumers' assets classified as Level 3 represented one percent of Consumers' total assets measured at fair value.
Assets and Liabilities Measured at Fair Value on a Recurring Basis using Significant Level 3 Inputs
In Millions  
    Three Months Ended     Nine Months Ended  
September 30   2011     2010     2011     2010  
 
CMS Energy, including Consumers
                                
Balance at beginning of period
   $ —     $ (5 )   $ (3 )   $ (8 )
Total gains (losses) included in earnings1
     (1 )     2       (1 )     4  
Total gains (losses) offset through regulatory accounting
     (1 )     3       2       4  
Settlements
     1       (3 )     1       (3 )
 
Balance at end of period
   $ (1 )   $ (3 )   $ (1 )   $ (3 )
 
Unrealized gains (losses) included in earnings relating to assets and liabilities still held at end of period1
   $ (1 )   $ 2     $ —     $ 4  
 
Consumers
                                
Balance at beginning of period
   $ 3     $ —     $ 1     $ —  
Total gains (losses) offset through regulatory accounting
     (1 )     3       2       4  
Settlements
     —       (2 )     (1 )     (3 )
 
Balance at end of period
   $ 2     $ 1     $ 2     $ 1  
 
1   CMS Energy records realized and unrealized gains and losses for Level 3 recurring fair values in earnings as a component of operating revenue or maintenance and other operating expenses on its consolidated statements of income.
  
Assets and Liabilities Measured at Fair Value on a Nonrecurring Basis 
                                 
In Millions  
    Level 1     Level 2     Level 3     Losses  
 
CMS Energy, including Consumers
                                
Assets held for sale
   $ —     $ —     $ 7     $ (4 )
 
 
Consumers Energy Company [Member]
   
Assets and Liabilities Measured at Fair Value on a Recurring Basis
In Millions  
    Total     Level 1     Level 2     Level 3  
 
CMS Energy, including Consumers
                                
Assets
                                
Cash equivalents
   $ 512     $ 512     $ —     $ —  
Restricted cash equivalents
     14       14       —       —  
Nonqualified deferred compensation plan assets
     4       4       —       —  
SERP
                                
Cash equivalents
     1       1       —       —  
Mutual fund
     87       87       —       —  
State and municipal bonds
     26       —       26       —  
Derivative instruments
                                
Commodity contracts1
     2       —       —       2  
 
Total2
   $ 646     $ 618     $ 26     $ 2  
 
Liabilities
                                
Nonqualified deferred compensation plan liabilities
   $ 4     $ 4     $ —     $ —  
Derivative instruments
                                
Commodity contracts3
     3       —       —       3  
 
Total4
   $ 7     $ 4     $ —     $ 3  
 
Consumers
                                
Assets
                                
Cash equivalents
   $ 282     $ 282     $ —     $ —  
Restricted cash equivalents
     13       13       —       —  
CMS Energy common stock
     31       31       —       —  
Nonqualified deferred compensation plan assets
     3       3       —       —  
SERP
                                
Cash equivalents
     1       1       —       —  
Mutual fund
     57       57       —       —  
State and municipal bonds
     17       —       17       —  
Derivative instruments
                                
Commodity contracts
     2       —       —       2  
 
Total5
   $ 406     $ 387     $ 17     $ 2  
 
Liabilities
                                
Nonqualified deferred compensation plan liabilities
   $ 3     $ 3     $ —     $ —  
 
Total
   $ 3     $ 3     $ —     $ —  
 
1   This amount is gross and excludes the impact of offsetting derivative assets and liabilities under master netting arrangements, which was less than $1 million at September 30, 2011.
2   At September 30, 2011, CMS Energy's assets classified as Level 3 represented less than one percent of CMS Energy's total assets measured at fair value.
3   This amount is gross and excludes the impact of offsetting derivative assets and liabilities under master netting arrangements and offsetting cash margin deposits paid by CMS ERM to other parties, which was less than $1 million at September 30, 2011.
4   At September 30, 2011, CMS Energy's liabilities classified as Level 3 represented 43 percent of CMS Energy's total liabilities measured at fair value. The Level 3 liabilities consisted primarily of an electricity sales agreement held by CMS ERM.
5   At September 30, 2011, Consumers' assets classified as Level 3 represented less than one percent of Consumers' total assets measured at fair value.
 
                               
In Millions  
    Total     Level 1     Level 2     Level 3  
 
CMS Energy, including Consumers
                                
Assets
                                
Cash equivalents
   $ 183     $ 183     $ —     $ —  
Restricted cash equivalents
     6       6       —       —  
Nonqualified deferred compensation plan assets
     6       6       —       —  
SERP
                                
Cash equivalents
     1       1       —       —  
Mutual fund
     62       62       —       —  
State and municipal bonds
     28       —       28       —  
Derivative instruments
                                
Commodity contracts1
     1       —       —       1  
 
Total2
   $ 287     $ 258     $ 28     $ 1  
 
Liabilities
                                
Nonqualified deferred compensation plan liabilities
   $ 6     $ 6     $ —     $ —  
Derivative instruments
                                
Commodity contracts3
     4       —       —       4  
 
Total4
   $ 10     $ 6     $ —     $ 4  
 
Consumers
                                
Assets
                                
Cash equivalents
   $ 19     $ 19     $ —     $ —  
Restricted cash equivalents
     6       6       —       —  
CMS Energy common stock
     34       34       —       —  
Nonqualified deferred compensation plan assets
     4       4       —       —  
SERP
                                
Cash equivalents
     1       1       —       —  
Mutual fund
     39       39       —       —  
State and municipal bonds
     17       —       17       —  
Derivative instruments
                                
Commodity contracts
     1       —       —       1  
 
Total5
   $ 121     $ 103     $ 17     $ 1  
 
Liabilities
                                
Nonqualified deferred compensation plan liabilities
   $ 4     $ 4     $ —     $ —  
 
Total
   $ 4     $ 4     $ —     $ —  
 
1   This amount is gross and excludes the impact of offsetting derivative assets and liabilities under master netting arrangements, which was less than $1 million at December 31, 2010.
2   At December 31, 2010, CMS Energy's assets classified as Level 3 represented less than one percent of CMS Energy's total assets measured at fair value.
 
3   This amount is gross and excludes the impact of offsetting derivative assets and liabilities under master netting arrangements and offsetting cash margin deposits paid by CMS ERM to other parties, which was less than $1 million at December 31, 2010.
 
4   At December 31, 2010, CMS Energy's liabilities classified as Level 3 represented 40 percent of CMS Energy's total liabilities measured at fair value. The Level 3 liabilities consisted primarily of an electricity sales agreement held by CMS ERM.
 
5   At December 31, 2010, Consumers' assets classified as Level 3 represented one percent of Consumers' total assets measured at fair value.
Assets and Liabilities Measured at Fair Value on a Recurring Basis using Significant Level 3 Inputs
In Millions  
    Three Months Ended     Nine Months Ended  
September 30   2011     2010     2011     2010  
 
CMS Energy, including Consumers
                                
Balance at beginning of period
   $ —     $ (5 )   $ (3 )   $ (8 )
Total gains (losses) included in earnings1
     (1 )     2       (1 )     4  
Total gains (losses) offset through regulatory accounting
     (1 )     3       2       4  
Settlements
     1       (3 )     1       (3 )
 
Balance at end of period
   $ (1 )   $ (3 )   $ (1 )   $ (3 )
 
Unrealized gains (losses) included in earnings relating to assets and liabilities still held at end of period1
   $ (1 )   $ 2     $ —     $ 4  
 
Consumers
                                
Balance at beginning of period
   $ 3     $ —     $ 1     $ —  
Total gains (losses) offset through regulatory accounting
     (1 )     3       2       4  
Settlements
     —       (2 )     (1 )     (3 )
 
Balance at end of period
   $ 2     $ 1     $ 2     $ 1  
 
1   CMS Energy records realized and unrealized gains and losses for Level 3 recurring fair values in earnings as a component of operating revenue or maintenance and other operating expenses on its consolidated statements of income.