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Income Taxes (Narrative) (Details) (USD $) In Millions, unless otherwise specified | 3 Months Ended
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Mar. 31, 2014
Income Tax Benefits [Line Items] |
IRS audit, adjustments to income tax expense | $ 0
Consumers Energy Company [Member] |
Income Tax Benefits [Line Items] |
Reduction of income tax expense | 16
IRS audit, adjustments to income tax expense | 0
Consumers Energy Company [Member] | Electric Utility [Member] |
Income Tax Benefits [Line Items] |
Income tax benefits, to be returned to customers | 211
Tax benefit, distribution to customers, term | 5 years
Consumers Energy Company [Member] | Gas Utility [Member] |
Income Tax Benefits [Line Items] |
Income tax benefits, to be returned to customers | $ 264
Tax benefit, distribution to customers, term | 12 years

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- Definition The sum of the amounts of estimated penalties and interest recognized in the period arising from income tax examinations. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 740 -SubTopic 10 -Section 50 -Paragraph 15 -Subparagraph (c) -URI http://asc.fasb.org/extlink&oid=6907707&loc=d3e32718-109319 + Details
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