Income Taxes (Schedule of Effective Income Rate Reconciliation) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Income Taxes [Line Items]
Income from continuing operations before income taxes	$ 1,123	$ 954	$ 902
Income tax expense at statutory rate	236	200	189
Increase (decrease) in income taxes from:
State and local income taxes, net of federal effect	60	31	51
Renewable energy tax credits	(72)	(58)	(51)
TCJA excess deferred taxes	(43)	(40)	(65)
Deferred tax adjustment	(16)	0	0
Taxes attributable to noncontrolling interests	12	17	5
Accelerated flow-through of regulatory tax benefits	0	0	(39)
Other, net	(1)	(3)	3
Income tax expense	$ 176	$ 147	$ 93
Effective tax rate	15.70%	15.40%	10.30%
Consumers Energy Company
Income Taxes [Line Items]
Income from continuing operations before income taxes	$ 1,209	$ 1,028	$ 1,085
Income tax expense at statutory rate	254	216	228
Increase (decrease) in income taxes from:
State and local income taxes, net of federal effect	59	36	59
Renewable energy tax credits	(54)	(46)	(46)
TCJA excess deferred taxes	(43)	(40)	(65)
Deferred tax adjustment	(16)	0	0
Accelerated flow-through of regulatory tax benefits	0	0	(39)
Other, net	0	(5)	3
Income tax expense	$ 200	$ 161	$ 140
Effective tax rate	16.50%	15.70%	12.90%
Consumers Energy Company | Non-Michigan Jurisdiction
Increase (decrease) in income taxes from:
State and local income taxes, net of federal effect		$ (13)