Income Taxes (Schedule Of Effective Income Rate Reconciliation) (Details) - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022
Income Taxes [Line Items]
U.S. federal income tax rate	21.00%	21.00%
Increase (decrease) in income taxes from:
State and local income taxes, net of federal effect	1.70%	5.60%
Renewable energy tax credits	(6.90%)	(5.80%)
TCJA excess deferred taxes	(3.90%)	(7.20%)
Accelerated flow-through of regulatory tax benefits	0.00%	(4.30%)
Other, net	0.80%	0.70%
Effective tax rate	12.70%	10.00%
Consumers Energy Company
Income Taxes [Line Items]
U.S. federal income tax rate	21.00%	21.00%
Increase (decrease) in income taxes from:
State and local income taxes, net of federal effect	2.90%	5.30%
Renewable energy tax credits	(4.50%)	(4.30%)
TCJA excess deferred taxes	(3.70%)	(5.90%)
Accelerated flow-through of regulatory tax benefits	0.00%	(3.50%)
Other, net	(0.10%)	0.10%
Effective tax rate	15.60%	12.70%
Consumers Energy Company | Non-Michigan Jurisdiction
Increase (decrease) in income taxes from:
Reversal of tax reserve	$ 13