Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019
Accounts receivable and accrued revenue, ALLOWANCE	$ 29	$ 20
Notes receivable, ALLOWANCE	32	33
Accounts and notes receivable, ALLOWANCE	$ 91	$ 0
Common stock authorized (in shares)	350,000,000.0	350,000,000.0
Common stock outstanding (in shares)	288,900,000	283,900,000
Consumers Energy Company
Accounts receivable and accrued revenue, ALLOWANCE	$ 29	$ 20
Common stock authorized (in shares)	125,000,000.0	125,000,000.0
Common stock outstanding (in shares)	84,100,000	84,100,000