Income Taxes (Tables)

12 Months Ended

Dec. 31, 2012

Income Tax Disclosure [Abstract]

Schedule of Effective Income Tax Rate Reconciliation [Table Text Block]

	2012			2011			2010
	(In millions)
Income before income taxes	$	960		$	991		$	962
Income tax expense at 35% statutory rate	$	336		$	347		$	337
Production tax credits	(49		)	(6		)	(33		)
Investment tax credits	(6		)	(6		)	(6		)
Depreciation	(4		)	(4		)	(4		)
Employee Stock Ownership Plan dividends	(4		)	(4		)	(5		)
Domestic production activities deduction	(14		)	(7		)	(7		)
Settlement of Federal tax audit	—			—			(12		)
State and local income taxes, net of federal benefit	37			37			44
Enactment of Michigan Corporate Income Tax, net of federal expense	—			(87		)	—
Other, net	(10		)	(2		)	1
Income tax expense	$	286		$	268		$	315
Effective income tax rate	29.8		%	27.0		%	32.7		%

Schedule of Components of Income Tax Expense (Benefit) [Table Text Block]

Components of income tax expense were as follows:

	2012			2011			2010
Current income tax expense (benefit)	(In millions)
Federal	$	190		$	27		$	(168	)
State and other income tax	49			21			26
Total current income taxes	239			48			(142		)
Deferred income tax expense (benefit)
Federal	39			318			415
State and other income tax	8			(98		)	42
Total deferred income taxes	47			220			457
Total income taxes from continuing operations	286			268			315
Discontinued operations	(29		)	(1		)	(4		)
Total	$	257		$	267		$	311

Schedule of Deferred Tax Assets and Liabilities [Table Text Block]

Deferred tax assets (liabilities) were comprised of the following at December 31:

	2012			2011
	(In millions)
Property, plant and equipment	$	(3,389	)	$	(3,131	)
Securitized regulatory assets	(256		)	(360		)
Alternative minimum tax credit carry-forwards	254			294
Merger basis differences	42			50
Pension and benefits	(33		)	(39		)
Other comprehensive income	101			99
Derivative assets and liabilities	66			64
State net operating loss and credit carry-forwards	37			30
Other	41			(45		)
	(3,137		)	(3,038		)
Less valuation allowance	(33		)	(27		)
	$	(3,170	)	$	(3,065	)
Current deferred income tax assets	$	21		$	51
Long-term deferred income tax liabilities	(3,191		)	(3,116		)
	$	(3,170	)	$	(3,065	)
Deferred income tax assets	$	1,038		$	1,048
Deferred income tax liabilities	(4,208		)	(4,113		)
	$	(3,170	)	$	(3,065	)

Unrecognized Tax Benefits [Table Text Block]

A reconciliation of the beginning and ending amount of unrecognized tax benefits is as follows:

	2012			2011			2010
	(In millions)
Balance at January 1	$	48		$	28		$	81
Additions for tax positions of prior years	—			27			4
Reductions for tax positions of prior years	(2		)	(4		)	(4		)
Additions for tax positions of current year	1			1			—
Settlements	(30		)	(3		)	(53		)
Lapse of statute of limitations	(6		)	(1		)	—
Balance at December 31	$	11		$	48		$	28