Other Income and Other Expense (Components of Other Expense) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Other Income and Expenses [Line Items]
Donations	$ (6)	$ (35)	$ (3)
Civic and political expenditures	(5)	(5)	(6)
Loss on reacquired and extinguished debt	0	(16)	0
All other	(7)	(6)	(4)
Total other expense	(18)	(62)	(13)
Consumers Energy Company
Other Income and Expenses [Line Items]
Donations	(6)	(33)	(3)
Civic and political expenditures	(5)	(5)	(6)
All other	(7)	(5)	(4)
Total other expense	$ (18)	$ (43)	$ (13)