Regulatory Matters (Tables) (Consumers Energy Company [Member])

12 Months Ended

Dec. 31, 2011

Schedule of Regulatory Assets and Liabilities

December 31	End of Recovery or Refund Period	2011		2010
		In Millions
Regulatory assets
Current
Postretirement benefits (Note 12)1	2011	$	—	$	19
Other2	2012		1		—
Total current regulatory assets		$	1	$	19
Non-current
Postretirement benefits (Note 12)1	various	$	1,665	$	1,364
Securitized costs (Note 7)3	2015		252		310
MGP sites (Note 5)3	various		156		58
ARO (Note 17)3	various		114		107
Big Rock nuclear decommissioning and related costs3	n/a		85		85
Electric revenue decoupling mechanism	n/a		59		28
Unamortized debt costs3	various		44		52
Energy optimization plan incentive	various		26		14
Stranded costs2	2013		23		46
Gas revenue decoupling mechanism	n/a		21		11
Uncollectible expense tracking mechanism2	2012		2		3
Other2	various		19		15
Total non-current regulatory assets		$	2,466	$	2,093
Total regulatory assets		$	2,467	$	2,112
Regulatory liabilities
Current
DOE settlement	2012	$	120	$	—
Self-implemented rate refunds	2011		—		14
Refund of revenue in excess of nuclear decommissioning costs	2011		—		7
Other	2012		5		1
Total current regulatory liabilities		$	125	$	22
Non-current
Cost of removal	various	$	1,364	$	1,311
Income taxes, net (Note 13)	various		181		410
Renewable energy plan	n/a		161		101
ARO (Note 17)	various		113		122
Energy optimization plan	n/a		45		34
Other	various		11		10
Total non-current regulatory liabilities		$	1,875	$	1,988
Total regulatory liabilities		$	2,000	$	2,010

¹ The regulatory asset associated with postretirement benefits is offset partially by liabilities. The net amount is included in rate base, thereby providing a return.

²  These regulatory assets either are included in rate base (or are expected to be included, for costs incurred subsequent to the most recently approved rate case), thereby providing a return on expenditures, or provide a specific return on investment authorized by the MPSC.

³ These regulatory assets represent expenditures for which the MPSC has provided, or Consumers expects, recovery without a return on investment.

Schedule of Assets and Liabilities for PSCR and GCR Underrecoveries and Overrecoveries

December 31	2011		2010
	In Millions
Accrued power supply revenue	$	—	$	15
Accrued rate refunds		30		19

Power Supply Cost Recover (PSCR) [Member]

Schedule of Reconciliation Filings Pending with MPSC

PSCR Year	Date Filed		Net Underrecovery		PSCR Cost of Power Sold
2010		March 2011	$	15 million	$	1.7 billion

Gas Cost Recover (GCR) [Member]

Schedule of Reconciliation Filings Pending with MPSC

GCR Year	Date Filed	Net Overrecovery		GCR Cost of Gas Sold
2009-2010	June 2010		$1 million		$1.3 billion
2010-2011	June 2011		6 million		1.2 billion

2010 Gas Rate Case [Member]

Schedule Of Annual Rate Increase Authorized And Requested

Components of the Rate Increase	Increase Authorized by the MPSC			Increase Originally Requested by Consumers		Difference
	In Millions
Investment in rate base	$	29		$	30	$	(1	)
Impact of sales declines		15			4		11
Operating and maintenance costs		2			16		(14	)
Cost of capital		(15	)		5		(20	)
Total	$	31		$	55	$	(24	)