Notes Receivable (Schedule Of Current And Non-Current Notes Receivable) (Details) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019
Accounts, Notes, Loans and Financing Receivable [Line Items]
EnerBank notes receivable, net of allowance for loan losses	$ 275	$ 242
Total notes receivable	2,887	2,500
Consumers Energy Company
Accounts, Notes, Loans and Financing Receivable [Line Items]
DB SERP note receivable – related party	7	7
DB SERP note receivable – related party	100	96
Total notes receivable	107	103
EnerBank
Accounts, Notes, Loans and Financing Receivable [Line Items]
EnerBank notes receivable, net of allowance for loan losses	275	242
EnerBank notes receivable, net of allowance for loan losses	$ 2,612	$ 2,258