Notes Receivable (Schedule Of Current And Non-Current Notes Receivable) (Details) (USD $) In Millions, unless otherwise specified	Mar. 31, 2014		Dec. 31, 2013
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current notes receivable	$ 69		$ 63
Total notes receivable	713		698
Consumers Energy Company [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current notes receivable			14
Total notes receivable			14
EnerBank [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current notes receivable	68		48
Noncurrent notes receivable	644		635
Total notes receivable	712	[1]	683	[1]
Other [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current notes receivable	1		15
Other [Member] | Consumers Energy Company [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current notes receivable			$ 14

[1] Includes current portion of notes receivable of $68 million at March 31, 2014 and $48 million at December 31, 2013.