Financings (Dividend Restrictions) (Details) (USD $) | 9 Months Ended |
|---|---|
Sep. 30, 2011 | |
| Limitation on payment of stock dividends | $ 1,200,000,000 |
Consumers Energy Company [Member] | |
| Common stock dividends from Consumers | 292,000,000 |
| Unrestricted retained earnings | $ 510,000,000 |