Income Taxes (Schedule Of Effective Income Rate Reconciliation) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Income Taxes [Line Items]
Income from continuing operations before income taxes	$ 902	$ 823	$ 809
Income tax expense at statutory rate	189	173	170
Increase (decrease) in income taxes from:
State and local income taxes, net of federal effect	51	39	44
TCJA excess deferred taxes	(65)	(50)	(35)
Production tax credits	(45)	(40)	(28)
Accelerated flow-through of regulatory tax benefits	(39)	(28)	(13)
Research and development tax credits, net	(2)	(3)	(11)
Refund of alternative minimum tax sequestration	0	0	(9)
Other, net	4	4	(3)
Income tax expense	$ 93	$ 95	$ 115
Effective tax rate	10.30%	11.50%	14.20%
Income tax benefit for sequestered amounts	$ 0	$ 0	$ 9
Research Tax Credit Carryforward
Increase (decrease) in income taxes from:
Increase in tax credit carryforward	1		9
Consumers Energy Company
Income Taxes [Line Items]
Income from continuing operations before income taxes	1,085	1,024	989
Income tax expense at statutory rate	228	215	208
Increase (decrease) in income taxes from:
State and local income taxes, net of federal effect	59	54	47
TCJA excess deferred taxes	(65)	(50)	(35)
Production tax credits	(40)	(33)	(19)
Accelerated flow-through of regulatory tax benefits	(39)	(28)	(13)
Research and development tax credits, net	(1)	(3)	(11)
Other, net	(2)	1	(4)
Income tax expense	$ 140	$ 156	$ 173
Effective tax rate	12.90%	15.20%	17.50%
Consumers Energy Company | Research Tax Credit Carryforward
Increase (decrease) in income taxes from:
Increase in tax credit carryforward			$ 8