Income Taxes (Details Textuals) (USD $)	3 Months Ended	12 Months Ended
	Jun. 30, 2011	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Income Tax Disclosure [Abstract]
Production Tax Credits Earned In Prior Years But Not Utilized Carried Forward Indefinitely As Alternative Minimum Tax Credits		$ 266,000,000	$ 254,000,000
Deferred Tax Assets State Net Operating Loss and Credit Carry Forwards		43,000,000	37,000,000
Valuation Allowance, Amount		37,000,000	33,000,000
Unrecognized Tax Benefits that Would Impact Effective Tax Rate		2,000,000	3,000,000
Significant Change in Unrecognized Tax Benefits is Reasonably Possible, Amount of Unrecorded Benefit		1,000,000
Unrecognized Tax Benefits, Interest on Income Taxes Accrued		1,000,000	1,000,000
Unrecognized Tax Benefits, Income Tax Penalties Accrued		0
Unrecognized Tax Benefits, Interest on Income Taxes Expense		0	(1,000,000)	(2,000,000)
Michigan Corporate Income Tax	6.00%
Time Period for the MBT Deferred Tax Asset	1 year
Net impact of Michigan Corporate Income Tax enactment, decrease in deferred tax liabilities attributable to non-utilities	87,000,000
Consistent with Original Treatment of Deferred Tax Liabilities No Cash Flow Impact	$ 0