Consolidated Statements of Comprehensive Income (Unaudited) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Net Income	$ 342	$ 243
Retirement Benefits Liability
Amortization of net actuarial loss, net of tax	1	1
Derivatives
Unrealized gain (loss) on derivative instruments, net of tax of $— and $(1)	1	(4)
Other Comprehensive Income (Loss)	2	(3)
Comprehensive Income	344	240
Comprehensive Loss Attributable to Noncontrolling Interests	(7)	0
Comprehensive Income Attributable to CMS Energy	351	240
Consumers Energy Company
Net Income	336	235
Retirement Benefits Liability
Amortization of net actuarial loss, net of tax	0	0
Derivatives
Other Comprehensive Income (Loss)	0	0
Comprehensive Income	$ 336	$ 235