XML 57 R43.htm IDEA: XBRL DOCUMENT ﻿
v2.3.0.11

Regulatory Matters (Schedule of GCR Reconciliation Filing Pending with the MPSC) (Details) (USD $) In Millions | 3 Months Ended | 6 Months Ended | 12 Months Ended | 3 Months Ended | 6 Months Ended
--- | --- | --- | --- | --- | ---
Jun. 30, 2011 | Jun. 30, 2010 | Jun. 30, 2011 | Jun. 30, 2010 | Mar. 31, 2011 Gas Cost Recover (GCR) [Member] Consumers Energy Company [Member] | Mar. 31, 2010 Gas Cost Recover (GCR) [Member] Consumers Energy Company [Member] | Jun. 30, 2011 Consumers Energy Company [Member] | Jun. 30, 2010 Consumers Energy Company [Member] | Jun. 30, 2011 Consumers Energy Company [Member] | Jun. 30, 2010 Consumers Energy Company [Member]
Date Of Filing |  |  |  |  | June 2011 | June 2010 |  |  |  |
Net Over-/(Under) Recovery of GCR Expense, Including Interest |  |  |  |  | $ 6 | $ 1 |  |  |  |
Cost of gas sold | $ 220 | $ 178 | $ 988 | $ 956 | $ 1,200 | $ 1,300 | $ 197 | $ 163 | $ 950 | $ 909

X
- Definition Date of Filing + Details
Name: | cms_DateOfFiling
Namespace Prefix: | cms
Data Type: | invest:dateStringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Net over-/(under-) recovery of expense, including interest. + Details
Name: | cms_NetOverUnderRecoveryOfExpenseIncludingInterest
Namespace Prefix: | cms
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Cost of natural gas purchased and associated transportation and storage costs during the period. + Details
Name: | us-gaap_CostOfNaturalGasPurchases
Namespace Prefix: | us-gaap
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration