Consolidated Balance Sheets (Parenthetical) - USD ($) shares in Millions, $ in Millions	Jun. 30, 2018	Dec. 31, 2017
Accounts receivable and accrued revenue ALLOWANCE	$ 20	$ 20
Accounts and notes receivable ALLOWANCE	$ 23	$ 20
Common Stock, Shares Authorized (in shares)	350.0	350.0
Common Stock, Shares, Outstanding	283.2	281.6
Consumers Energy Company
Accounts receivable and accrued revenue ALLOWANCE	$ 20	$ 20
Common Stock, Shares Authorized (in shares)	125.0	125.0
Common Stock, Shares, Outstanding	84.1	84.1