CMS Energy Corporation Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Millions	Dec. 31, 2021	Dec. 31, 2020
Accounts receivable and accrued revenue, allowance	$ 20	$ 29
Common stock authorized (in shares)	350,000,000	350,000,000.0
Common stock outstanding (in shares)	289,800,000	288,900,000
Preferred stock authorized (in shares)	10,000,000
Series C Preferred Stock Depositary Shares
Preferred stock outstanding (in shares)	9,200,000
Preferred stock authorized (in shares)	9,200,000