Fair Value Measurements (Tables)

9 Months Ended

12 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.