Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Millions	Jun. 30, 2017	Dec. 31, 2016
Allowances for doubtful accounts receivable	$ 22	$ 24
Allowances for doubtful notes receivable	$ 18	$ 16
Common stock, shares authorized	350,000,000	350,000,000
Common stock, shares outstanding	281,600,000	279,200,000
Consumers Energy Company [Member]
Allowances for doubtful accounts receivable	$ 22	$ 24
Common stock, shares authorized	125,000,000	125,000,000
Common stock, shares outstanding	84,100,000	84,100,000