Fair Value Measurements (Tables)

3 Months Ended

Mar. 31, 2013

Assets And Liabilities Measured At Fair Value On A Recurring Basis

In Millions
	March 31, 2013												December 31, 2012
				Level												Level
	Total			1			2			3			Total			1			2			3
CMS Energy, including Consumers
Assets
Cash equivalents		$	485		$	485		$	-		$	-		$	53		$	53		$	-		$	-
Restricted cash equivalents			13			13			-			-			14			14			-			-
Nonqualified deferred    compensation plan assets			5			5			-			-			5			5			-			-
DB SERP
Cash equivalents			1			1			-			-			2			2			-			-
Mutual funds			141			141			-			-			126			126			-			-
Derivative instruments
Commodity contracts			1			-			-			1			3			-			-			3
Total		$	646		$	645		$	-		$	1		$	203		$	200		$	-		$	3
Liabilities
Nonqualified deferred    compensation plan liabilities		$	5		$	5		$	-		$	-		$	5		$	5		$	-		$	-
Derivative instruments
Commodity contracts			3			-			2			1			4			-			3			1
Total		$	8		$	5		$	2		$	1		$	9		$	5		$	3		$	1
Consumers
Assets
Cash equivalents		$	289		$	289		$	-		$	-		$	-		$	-		$	-		$	-
Restricted cash equivalents			13			13			-			-			13			13			-			-
CMS Energy common stock			30			30			-			-			32			32			-			-
Nonqualified deferred    compensation plan assets			4			4			-			-			4			4			-			-
DB SERP
Cash equivalents			1			1			-			-			1			1			-			-
Mutual funds			99			99			-			-			85			85			-			-
Derivative instruments
Commodity contracts			-			-			-			-			2			-			-			2
Total		$	436		$	436		$	-		$	-		$	137		$	135		$	-		$	2
Liabilities
Nonqualified deferred    compensation plan liabilities		$	4		$	4		$	-		$	-		$	4		$	4		$	-		$	-
Total		$	4		$	4		$	-		$	-		$	4		$	4		$	-		$	-

Consumers Energy Company [Member]

Assets And Liabilities Measured At Fair Value On A Recurring Basis

In Millions
	March 31, 2013												December 31, 2012
				Level												Level
	Total			1			2			3			Total			1			2			3
CMS Energy, including Consumers
Assets
Cash equivalents		$	485		$	485		$	-		$	-		$	53		$	53		$	-		$	-
Restricted cash equivalents			13			13			-			-			14			14			-			-
Nonqualified deferred    compensation plan assets			5			5			-			-			5			5			-			-
DB SERP
Cash equivalents			1			1			-			-			2			2			-			-
Mutual funds			141			141			-			-			126			126			-			-
Derivative instruments
Commodity contracts			1			-			-			1			3			-			-			3
Total		$	646		$	645		$	-		$	1		$	203		$	200		$	-		$	3
Liabilities
Nonqualified deferred    compensation plan liabilities		$	5		$	5		$	-		$	-		$	5		$	5		$	-		$	-
Derivative instruments
Commodity contracts			3			-			2			1			4			-			3			1
Total		$	8		$	5		$	2		$	1		$	9		$	5		$	3		$	1
Consumers
Assets
Cash equivalents		$	289		$	289		$	-		$	-		$	-		$	-		$	-		$	-
Restricted cash equivalents			13			13			-			-			13			13			-			-
CMS Energy common stock			30			30			-			-			32			32			-			-
Nonqualified deferred    compensation plan assets			4			4			-			-			4			4			-			-
DB SERP
Cash equivalents			1			1			-			-			1			1			-			-
Mutual funds			99			99			-			-			85			85			-			-
Derivative instruments
Commodity contracts			-			-			-			-			2			-			-			2
Total		$	436		$	436		$	-		$	-		$	137		$	135		$	-		$	2
Liabilities
Nonqualified deferred    compensation plan liabilities		$	4		$	4		$	-		$	-		$	4		$	4		$	-		$	-
Total		$	4		$	4		$	-		$	-		$	4		$	4		$	-		$	-