Income Taxes (Tables)

12 Months Ended

Dec. 31, 2011

Income Taxes [Abstract]

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

	2011			2010			2009
	(In millions)
Income before income taxes	$	987		$	950		$	782
Income tax expense at 35% statutory rate	$	345		$	333		$	274
Production tax credits	(6		)	(33		)	(12		)
Investment tax credits	(6		)	(6		)	(7		)
Depreciation	(4		)	(4		)	(4		)
Employee Stock Ownership Plan dividends	(4		)	(5		)	(5		)
Medicare part D subsidy	—			—			(6		)
Domestic production activities deduction	(7		)	(7		)	(5		)
Goodwill attributed to the sale of Gas Utility subsidiaries	—			—			4
Settlement of Federal tax audit	—			(12		)	(11		)
State and local income taxes, net of federal benefit	37			44			25
Enactment of Michigan Corporate Income Tax, net of federal expense	(87		)	—			—
Other, net	(1		)	1			(6		)
Income tax expense	$	267		$	311		$	247
Effective income tax rate	27.1		%	32.7		%	31.6		%

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

Components of income tax expense were as follows:

	2011			2010			2009
	(In millions)
Current income tax expense (benefit)
Federal	$	25		$	(172	)	$	25
State and other income tax	22			26			17
Total current income taxes	47			(146		)	42
Deferred income tax expense (benefit)
Federal	318			415			182
State and other income tax	(98		)	42			23
Total deferred income taxes	220			457			205
Total	$	267		$	311		$	247

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

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

	2011			2010
	(In millions)
Property, plant and equipment	$	(3,131	)	$	(2,558	)
Securitized regulatory assets	(360		)	(396		)
Alternative minimum tax credit carry-forwards	294			337
Merger basis differences	50			49
Pension and benefits	(39		)	(36		)
Other comprehensive income	99			83
Derivative assets and liabilities	64			29
State net operating loss and credit carry-forwards	30			33
Other	(45		)	(2		)
	(3,038		)	(2,461		)
Less valuation allowance	(27		)	(32		)
	$	(3,065	)	$	(2,493	)
Current deferred income tax assets	$	51		$	139
Long-term deferred income tax liabilities	(3,116		)	(2,632		)
	$	(3,065	)	$	(2,493	)
Deferred income tax assets	$	1,048		$	1,418
Deferred income tax liabilities	(4,113		)	(3,911		)
	$	(3,065	)	$	(2,493	)

Unrecognized Tax Benefits [Table Text Block]

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

	2011			2010			2009
	(In millions)
Balance at January 1	$	28		$	81		$	72
Additions for tax positions of prior years	27			4			15
Reductions for tax positions of prior years	(4		)	(4		)	(5		)
Additions for tax positions related to the current year	1			—			7
Settlements	(3		)	(53		)	(5		)
Lapse of statute of limitations	(1		)	—			(3		)
Balance at December 31	$	48		$	28		$	81