Plant, Property, and Equipment (Property, Plant and Equipment Table) (Details) (USD $) In Millions, unless otherwise specified	1 Months Ended		12 Months Ended
	Dec. 31, 2013 site		Dec. 31, 2013 site		Dec. 31, 2012		Dec. 31, 2011
Public Utility, Property, Plant and Equipment [Line Items]
Construction work in progress	$ 1,149		$ 1,149		$ 1,080
Accumulated Depreciation and Amortization	(5,087)		(5,087)		(5,121)
Public Utilities, Property, Plant and Equipment, Net	12,246	[1]	12,246	[1]	11,551	[1]
Public Utilities, Property Plant and Equipment Additions			1,300		999
Public Utilities, Property Plant and Equipment Disposals			156		168
Consumers Energy Company [Member]
Public Utility, Property, Plant and Equipment [Line Items]
Capital Leased Assets, Gross	291		291		285		280
Construction work in progress	1,147		1,147		1,080
Accumulated Depreciation and Amortization	(5,022)		(5,022)		(5,061)
Public Utilities, Property, Plant and Equipment, Net	12,169	[1]	12,169	[1]	11,475	[1]
Public Utilities, Property Plant and Equipment Additions			1,300		999
Public Utilities, Property Plant and Equipment Disposals			156		168
Number of units planned to be retired	10		10
Consumers Energy Company [Member] | Coal Fueled Electric Generating Units [Member]
Public Utility, Property, Plant and Equipment [Line Items]
Number of units planned to be retired	7		7
Consumers Energy Company [Member] | Gas Fueled Electric Generating Units [Member]
Public Utility, Property, Plant and Equipment [Line Items]
Number of units planned to be retired	3		3
Electricity Generation Plant, Non-Nuclear [Member]
Public Utility, Property, Plant and Equipment [Line Items]
Public Utilities, Property, Plant and Equipment, Generation or Processing	3,992		3,992		4,254
Electricity Generation Plant, Non-Nuclear [Member] | Minimum [Member]
Public Utility, Property, Plant and Equipment [Line Items]
Estimated Depreciable Life in Years, Generation			22 years
Electricity Generation Plant, Non-Nuclear [Member] | Maximum [Member]
Public Utility, Property, Plant and Equipment [Line Items]
Estimated Depreciable Life in Years, Generation			125 years
Electricity Generation Plant, Non-Nuclear [Member] | Consumers Energy Company [Member]
Public Utility, Property, Plant and Equipment [Line Items]
Public Utilities, Property, Plant and Equipment, Generation or Processing	3,992		3,992		4,254
Decrease of net plant, property, and equipment			362
Electricity Generation Plant, Non-Nuclear [Member] | Consumers Energy Company [Member] | Minimum [Member]
Public Utility, Property, Plant and Equipment [Line Items]
Estimated Depreciable Life in Years, Generation			22 years
Electricity Generation Plant, Non-Nuclear [Member] | Consumers Energy Company [Member] | Maximum [Member]
Public Utility, Property, Plant and Equipment [Line Items]
Estimated Depreciable Life in Years, Generation			125 years
Electric Distribution [Member]
Public Utility, Property, Plant and Equipment [Line Items]
Public Utilities, Property, Plant and Equipment, Distribution	6,140		6,140		5,831
Electric Distribution [Member] | Minimum [Member]
Public Utility, Property, Plant and Equipment [Line Items]
Estimated Depreciable Life in Years, Distribution			23 years
Electric Distribution [Member] | Maximum [Member]
Public Utility, Property, Plant and Equipment [Line Items]
Estimated Depreciable Life in Years, Distribution			75 years
Electric Distribution [Member] | Consumers Energy Company [Member]
Public Utility, Property, Plant and Equipment [Line Items]
Public Utilities, Property, Plant and Equipment, Distribution	6,140		6,140		5,831
Electric Distribution [Member] | Consumers Energy Company [Member] | Minimum [Member]
Public Utility, Property, Plant and Equipment [Line Items]
Estimated Depreciable Life in Years, Distribution			23 years
Electric Distribution [Member] | Consumers Energy Company [Member] | Maximum [Member]
Public Utility, Property, Plant and Equipment [Line Items]
Estimated Depreciable Life in Years, Distribution			75 years
Electric Other [Member]
Public Utility, Property, Plant and Equipment [Line Items]
Public Utilities, Property, Plant and Equipment, Other Property, Plant and Equipment	770		770		677
Electric Other [Member] | Minimum [Member]
Public Utility, Property, Plant and Equipment [Line Items]
Estimated Depreciable Life in Years, Other			5 years
Electric Other [Member] | Maximum [Member]
Public Utility, Property, Plant and Equipment [Line Items]
Estimated Depreciable Life in Years, Other			50 years
Electric Other [Member] | Consumers Energy Company [Member]
Public Utility, Property, Plant and Equipment [Line Items]
Public Utilities, Property, Plant and Equipment, Other Property, Plant and Equipment	770		770		677
Electric Other [Member] | Consumers Energy Company [Member] | Minimum [Member]
Public Utility, Property, Plant and Equipment [Line Items]
Estimated Depreciable Life in Years, Other			5 years
Electric Other [Member] | Consumers Energy Company [Member] | Maximum [Member]
Public Utility, Property, Plant and Equipment [Line Items]
Estimated Depreciable Life in Years, Other			50 years
Electric Capital Leases [Member]
Public Utility, Property, Plant and Equipment [Line Items]
Capital Leased Assets, Gross	284		284		279
Electric Capital Leases [Member] | Consumers Energy Company [Member]
Public Utility, Property, Plant and Equipment [Line Items]
Capital Leased Assets, Gross	284		284		279
Gas Distribution [Member]
Public Utility, Property, Plant and Equipment [Line Items]
Public Utilities, Property, Plant and Equipment, Distribution	3,015		3,015		2,861
Gas Distribution [Member] | Minimum [Member]
Public Utility, Property, Plant and Equipment [Line Items]
Estimated Depreciable Life in Years, Distribution			28 years
Gas Distribution [Member] | Maximum [Member]
Public Utility, Property, Plant and Equipment [Line Items]
Estimated Depreciable Life in Years, Distribution			80 years
Gas Distribution [Member] | Consumers Energy Company [Member]
Public Utility, Property, Plant and Equipment [Line Items]
Public Utilities, Property, Plant and Equipment, Distribution	3,015		3,015		2,861
Gas Distribution [Member] | Consumers Energy Company [Member] | Minimum [Member]
Public Utility, Property, Plant and Equipment [Line Items]
Estimated Depreciable Life in Years, Distribution			28 years
Gas Distribution [Member] | Consumers Energy Company [Member] | Maximum [Member]
Public Utility, Property, Plant and Equipment [Line Items]
Estimated Depreciable Life in Years, Distribution			80 years
Gas Transmission [Member]
Public Utility, Property, Plant and Equipment [Line Items]
Public Utilities, Property, Plant and Equipment, Transmission	821		821		770
Gas Transmission [Member] | Minimum [Member]
Public Utility, Property, Plant and Equipment [Line Items]
Estimated Depreciable Life in Years, Transmission			17 years
Gas Transmission [Member] | Maximum [Member]
Public Utility, Property, Plant and Equipment [Line Items]
Estimated Depreciable Life in Years, Transmission			75 years
Gas Transmission [Member] | Consumers Energy Company [Member]
Public Utility, Property, Plant and Equipment [Line Items]
Public Utilities, Property, Plant and Equipment, Transmission	821		821		770
Gas Transmission [Member] | Consumers Energy Company [Member] | Minimum [Member]
Public Utility, Property, Plant and Equipment [Line Items]
Estimated Depreciable Life in Years, Transmission			17 years
Gas Transmission [Member] | Consumers Energy Company [Member] | Maximum [Member]
Public Utility, Property, Plant and Equipment [Line Items]
Estimated Depreciable Life in Years, Transmission			75 years
Gas Underground Storage Facilities [Member]
Public Utility, Property, Plant and Equipment [Line Items]
Public Utilities, Property, Plant and Equipment, Other Property, Plant and Equipment	535	[2]	535	[2]	339	[2]
Gas Underground Storage Facilities [Member] | Minimum [Member]
Public Utility, Property, Plant and Equipment [Line Items]
Estimated Depreciable Life in Years, Other			29 years	[2]
Gas Underground Storage Facilities [Member] | Maximum [Member]
Public Utility, Property, Plant and Equipment [Line Items]
Estimated Depreciable Life in Years, Other			65 years	[2]
Gas Underground Storage Facilities [Member] | Consumers Energy Company [Member]
Public Utility, Property, Plant and Equipment [Line Items]
Public Utilities, Property, Plant and Equipment, Other Property, Plant and Equipment	535	[2]	535	[2]	339	[2]
Gas Underground Storage Facilities [Member] | Consumers Energy Company [Member] | Minimum [Member]
Public Utility, Property, Plant and Equipment [Line Items]
Estimated Depreciable Life in Years, Other			29 years	[2]
Gas Underground Storage Facilities [Member] | Consumers Energy Company [Member] | Maximum [Member]
Public Utility, Property, Plant and Equipment [Line Items]
Estimated Depreciable Life in Years, Other			65 years	[2]
Gas Other [Member]
Public Utility, Property, Plant and Equipment [Line Items]
Public Utilities, Property, Plant and Equipment, Other Property, Plant and Equipment	465		465		424
Gas Other [Member] | Minimum [Member]
Public Utility, Property, Plant and Equipment [Line Items]
Estimated Depreciable Life in Years, Other			5 years
Gas Other [Member] | Maximum [Member]
Public Utility, Property, Plant and Equipment [Line Items]
Estimated Depreciable Life in Years, Other			50 years
Gas Other [Member] | Consumers Energy Company [Member]
Public Utility, Property, Plant and Equipment [Line Items]
Public Utilities, Property, Plant and Equipment, Other Property, Plant and Equipment	465		465		424
Gas Other [Member] | Consumers Energy Company [Member] | Minimum [Member]
Public Utility, Property, Plant and Equipment [Line Items]
Estimated Depreciable Life in Years, Other			5 years
Gas Other [Member] | Consumers Energy Company [Member] | Maximum [Member]
Public Utility, Property, Plant and Equipment [Line Items]
Estimated Depreciable Life in Years, Other			50 years
Gas Capital Leases [Member]
Public Utility, Property, Plant and Equipment [Line Items]
Capital Leased Assets, Gross	7		7		6
Gas Capital Leases [Member] | Consumers Energy Company [Member]
Public Utility, Property, Plant and Equipment [Line Items]
Capital Leased Assets, Gross	7		7		6
Enterprises IPP [Member]
Public Utility, Property, Plant and Equipment [Line Items]
Plant, property, and equipment, gross	89		89		89
Enterprises IPP [Member] | Minimum [Member]
Public Utility, Property, Plant and Equipment [Line Items]
Estimated Depreciable Life in Years, Other			3 years
Enterprises IPP [Member] | Maximum [Member]
Public Utility, Property, Plant and Equipment [Line Items]
Estimated Depreciable Life in Years, Other			30 years
Enterprises Other [Member]
Public Utility, Property, Plant and Equipment [Line Items]
Plant, property, and equipment, gross	26		26		24
Enterprises Other [Member] | Minimum [Member]
Public Utility, Property, Plant and Equipment [Line Items]
Estimated Depreciable Life in Years, Other			3 years
Enterprises Other [Member] | Maximum [Member]
Public Utility, Property, Plant and Equipment [Line Items]
Estimated Depreciable Life in Years, Other			40 years
Other [Member]
Public Utility, Property, Plant and Equipment [Line Items]
Other non-utility property	40		40		38
Other [Member] | Minimum [Member]
Public Utility, Property, Plant and Equipment [Line Items]
Estimated Depreciable Life in Years, Other			1 year
Other [Member] | Maximum [Member]
Public Utility, Property, Plant and Equipment [Line Items]
Estimated Depreciable Life in Years, Other			51 years
Other [Member] | Consumers Energy Company [Member]
Public Utility, Property, Plant and Equipment [Line Items]
Other non-utility property	15		15		15
Other [Member] | Consumers Energy Company [Member] | Minimum [Member]
Public Utility, Property, Plant and Equipment [Line Items]
Estimated Depreciable Life in Years, Other			8 years
Other [Member] | Consumers Energy Company [Member] | Maximum [Member]
Public Utility, Property, Plant and Equipment [Line Items]
Estimated Depreciable Life in Years, Other			51 years
Base Natural Gas [Member] | Gas Underground Storage Facilities [Member]
Public Utility, Property, Plant and Equipment [Line Items]
Public Utilities, Property, Plant and Equipment, Other Property, Plant and Equipment	26		26		26
Base Natural Gas [Member] | Gas Underground Storage Facilities [Member] | Consumers Energy Company [Member]
Public Utility, Property, Plant and Equipment [Line Items]
Public Utilities, Property, Plant and Equipment, Other Property, Plant and Equipment	$ 26		$ 26		$ 26

[1] For the year ended December 31, 2013, utility plant additions were $1.3 billion and utility plant retirements were $156 million. Subject to a successful Securitization transaction, Consumers plans to retire seven smaller coal-fueled electric generating units and three smaller gas-fueled electric generating units by April 2016. Accordingly, Consumers removed the net book value of the ten units from plant, property, and equipment and recorded this amount as a regulatory asset at December 31, 2013. As a result, net plant, property, and equipment decreased by $362 million. For additional details, see Note 2, Regulatory Matters.For the year ended December 31, 2012, utility plant additions were $999 million and utility plant retirements were $168 million.

[2] Underground storage includes base natural gas of $26 million at December 31, 2013 and 2012. Base natural gas is not subject to depreciation.