Leases And Palisades Financing (Narrative) (Details) $ in Millions	1 Months Ended	12 Months Ended
	Dec. 31, 2016 USD ($)	Dec. 31, 2016 USD ($) MW	Dec. 31, 2015 USD ($)	Dec. 31, 2014 USD ($)
Consumers Energy Company [Member]
Leases [Line Items]
Finance Lease Term		15 years
Coal-Carrying Railcars [Member] | Consumers Energy Company [Member]
Leases [Line Items]
Operating leases without extension provisions, remaining term		7 years
Operating leases with extension provisions, remaining term		10 years
Gas Transportation Pipeline into Karn [Member] | Consumers Energy Company [Member]
Leases [Line Items]
Capital Lease Term		15 years
Capital Lease Remaining Term		5 years
Gas Transportation Pipeline into Zeeland [Member] | Consumers Energy Company [Member]
Leases [Line Items]
Capital Lease Term		5 years
Capital lease renewal term		5 years
Capital Lease Remaining Term		1 year
Minimum [Member] | Coal-Carrying Railcars [Member] | Consumers Energy Company [Member]
Leases [Line Items]
Operating leases, term		1 year
Minimum [Member] | Long-term PPAs [Member] | Consumers Energy Company [Member]
Leases [Line Items]
Lease term		1 year
Maximum [Member] | Coal-Carrying Railcars [Member] | Consumers Energy Company [Member]
Leases [Line Items]
Operating leases, term		15 years
Maximum [Member] | Vehicle Fleet Operations [Member] | Consumers Energy Company [Member]
Leases [Line Items]
Capital Lease Term		120 months
Maximum [Member] | Long-term PPAs [Member] | Consumers Energy Company [Member]
Leases [Line Items]
Lease term		16 years
Financing Leases [Member]
Leases [Line Items]
Finance Leases Lessee Balance Sheet Assets Amortization And Interest Charges | $	$ 17	$ 17	$ 18	$ 19
Financing Leases [Member] | Consumers Energy Company [Member]
Leases [Line Items]
Lease termination cost | $	$ 172
Palisades PPA [Member]
Leases [Line Items]
Unrecorded Unconditional Purchase Obligations, Maximum Quantity | MW		798
Palisades PPA [Member] | Consumers Energy Company [Member]
Leases [Line Items]
Unrecorded Unconditional Purchase Obligations, Maximum Quantity | MW		798