Other Income and Other Expense (Summary of Components of Other Income and Other Expense) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Other Income and Expenses [Line Items]
Allowance for equity funds used during construction	$ 29	$ 7	$ 6
Income from equity method investees	7	7	3
All other	11	13	5
Other income	207	195	19
Donations	(18)	(1)	(9)
Civic and political expenditures	(5)	(5)	(6)
All other	(9)	(7)	(12)
Total other expense	(32)	(13)	(27)
First mortgage bonds
Other Income and Expenses [Line Items]
Gain on extinguishment of debt	110	131	0
Nonrelated Party
Other Income and Expenses [Line Items]
Interest income	50	37	5
Consumers Energy Company
Other Income and Expenses [Line Items]
Allowance for equity funds used during construction	29	7	6
All other	9	12	4
Other income	85	49	17
Donations	(18)	(1)	(9)
Civic and political expenditures	(5)	(5)	(6)
All other	(7)	(6)	(10)
Total other expense	(30)	(12)	(25)
Consumers Energy Company | Nonrelated Party
Other Income and Expenses [Line Items]
Interest income	42	25	2
Consumers Energy Company | Related Party
Other Income and Expenses [Line Items]
Interest income	$ 5	$ 5	$ 5