Regulatory Matters (Narrative) (Details) $ in Millions		1 Months Ended						12 Months Ended
	Dec. 31, 2021 USD ($)	Jan. 31, 2023 USD ($)	Sep. 30, 2022 USD ($)	Jul. 31, 2022 USD ($)	Jun. 30, 2022	Apr. 30, 2022 USD ($)	Dec. 31, 2021 USD ($)	Dec. 31, 2022 USD ($) coal_fueled_electric_generating_unit site	Mar. 31, 2022 USD ($)	Dec. 31, 2021 USD ($)	Mar. 31, 2021 USD ($)	Dec. 31, 2020 USD ($)	Dec. 31, 2016 site	Dec. 31, 2015 site	Dec. 31, 2013 USD ($)	Oct. 31, 2022 USD ($)	Aug. 31, 2022 USD ($)
Public Utilities, General Disclosures [Line Items]
Incentive revenue								$ 8,596		$ 7,329		$ 6,418
Regulatory assets	$ 2,259						$ 2,259	3,595		2,259
Regulatory liabilities	146						146	104		146
Consumers revenues to be refunded								37				28
Subsequent Event
Public Utilities, General Disclosures [Line Items]
Proposed recovery term for 2022 underrecovery		3 years
Consumers Energy Company
Public Utilities, General Disclosures [Line Items]
Incentive revenue								8,151		7,021		6,189
Regulatory assets	2,259						2,259	$ 3,595		2,259
Number of units retired | site								10
Regulatory liabilities	146						146	$ 104		146
Consumers revenues to be refunded								37				28
Purchased and interchange power								1,867		1,599		1,454
Cost of gas sold								1,243		726		568
Consumers Energy Company | J.H. Campbell Generating Units
Public Utilities, General Disclosures [Line Items]
Rate of return on equity authorized					9.00%
Regulatory assets								$ 1,300
Costs of coal-fueled electric generating units to be retired | Consumers Energy Company
Public Utilities, General Disclosures [Line Items]
Regulatory assets, number of units | coal_fueled_electric_generating_unit								2
Coal-Fueled Electric Generation | Consumers Energy Company
Public Utilities, General Disclosures [Line Items]
Number of units retired | site													7
Gas-Fueled Electric Generation | Consumers Energy Company
Public Utilities, General Disclosures [Line Items]
Number of units retired | site														3
Energy Waste Reduction Plan Incentive | Consumers Energy Company
Public Utilities, General Disclosures [Line Items]
Authorized recovery collection																$ 46
Incentive revenue								$ 55		46
Requested recovery/collection								$ 55
Electric Rate Case | Consumers Energy Company
Public Utilities, General Disclosures [Line Items]
Impairment charge	4									45
Requested annual rate increase						$ 272
Requested annual rate increase, as a percent						10.25%
Amended requested annual rate increase			$ 292
Distributed generation cap, percent								2.00%
Electric Rate Case | Consumers Energy Company | Subsequent Event
Public Utilities, General Disclosures [Line Items]
Rate of return on equity authorized		9.90%
Surcharge for the recovery of excess distribution investments		$ 6
Distributed generation cap, percent		4.00%
Additional annual rate increase authorized		$ 155
Gas Rate Case | Consumers Energy Company
Public Utilities, General Disclosures [Line Items]
Rate of return on equity authorized				9.90%
Requested annual rate increase							$ 278
Requested annual rate increase, as a percent						10.25%	10.50%
Amended requested annual rate increase						$ 233
Additional annual rate increase authorized				$ 170
PSCR underrecoveries | Consumers Energy Company
Public Utilities, General Disclosures [Line Items]
Purchased and interchange power										2,100		1,800
Underrecovery for gas fuel and power supply costs	8						$ 8			8		(1)
Recommended disallowed costs																	$ 1
GCR underrecoveries | Consumers Energy Company
Public Utilities, General Disclosures [Line Items]
Underrecovery for gas fuel and power supply costs									$ 9		$ 2
Cost of gas sold									$ 700		$ 400
Voluntary refund mechanism | Consumers Energy Company
Public Utilities, General Disclosures [Line Items]
Regulatory liabilities								$ 22
Reserve for customer refunds | Consumers Energy Company
Public Utilities, General Disclosures [Line Items]
Regulatory liabilities	$ 2						$ 2	47		$ 2		$ 28
Consumers revenues to be refunded								15
Commitment to fund contributions to assist low-income customers								$ 10
Renewable energy grant | Consumers Energy Company
Public Utilities, General Disclosures [Line Items]
Proceeds from government grant															$ 69
MGP Sites | Consumers Energy Company
Public Utilities, General Disclosures [Line Items]
Number of former MGPs | site								23
Regulatory asset collection period								10 years