Notes Receivable (Schedule Of Current And Non-Current Notes Receivable) (Details) (USD $) In Millions, unless otherwise specified	Dec. 31, 2013		Dec. 31, 2012
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current notes receivable	$ 63		$ 41
Total notes receivable	698		561
Consumers Energy Company [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current notes receivable	14
Total notes receivable	14		16
EnerBank [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current notes receivable	48		40
Noncurrent notes receivable	635		504
Total notes receivable	683	[1]	544	[1]
Other [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current notes receivable	15		1
Noncurrent notes receivable			16
Other [Member] | Consumers Energy Company [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current notes receivable	14
Noncurrent notes receivable			$ 16

[1] Includes current portion of notes receivable of $48 million at December 31, 2013 and $40 million at December 31, 2012.