Income Taxes (Schedule of Effective Income Rate Reconciliation) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
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	5.50%	(0.50%)
Renewable energy tax credits	(6.00%)	(4.90%)
TCJA excess deferred taxes	(3.70%)	(3.70%)
Effective Income Tax Rate Reconciliation, Noncontrolling Interest Income (Loss), Percent	1.10%	0.70%
Other, net	0.20%	0.40%
Effective tax rate	18.10%	13.00%
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	4.90%	0.00%
Renewable energy tax credits	(4.00%)	(4.20%)
TCJA excess deferred taxes	(3.20%)	(3.20%)
Other, net	0.20%	0.50%
Effective tax rate	18.90%	14.10%
Consumers Energy Company | Non-Michigan Jurisdiction
Increase (decrease) in income taxes from:
State and local income taxes, net of federal effect	$ (13)