Income Taxes (Tables)

12 Months Ended

Dec. 31, 2012

Income Tax Disclosure [Abstract]

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

Total income tax expense varied from the statutory federal income tax rate for the following reasons:

	2012			2011			2010
	(In millions)
Income before income taxes	$	768		$	704		$	711
Income tax expense at 35% statutory rate	$	269		$	246		$	249
Investment tax credits	(6		)	(6		)	(6		)
Depreciation	3			3			3
Employee Stock Ownership Plan dividends	(3		)	(3		)	(3		)
Domestic production activities deduction	(16		)	(6		)	(6		)
State and other income taxes, net of federal benefit	40			39			40
Other, net	(5		)	(6		)	(7		)
Income Tax Expense	$	282		$	267		$	270
Effective income tax rate	36.7		%	38.0		%	38.0		%

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

Components of income tax expense (benefits) were as follows:

	2012			2011		2010
Current income tax expense (benefit)	(In millions)
Federal	$	267		$	15	$	(89	)
State and other income tax	67			21		37
Total current income taxes	334			36		(52		)
Deferred income tax expense (benefit)
Federal	(47		)	193		297
State and other income tax	(5		)	38		25
Total deferred income taxes	(52		)	231		322
Total	$	282		$	267	$	270

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	$	(2,578	)	$	(2,285	)
Securitized regulatory assets	(261		)	(384		)
Pension and benefits	73			67
Other comprehensive income	15			15
Other, net	(24		)	(182		)
	$	(2,775	)	$	(2,769	)
Current deferred income tax liability (included in Current Liabilities — Other)	$	(14	)	$	(68	)
Long-term deferred income tax liabilities	$	(2,761	)	$	(2,701	)
	$	(2,775	)	$	(2,769	)
Deferred income tax assets	$	557		$	608
Deferred income tax liabilities	(3,332		)	(3,377		)
	$	(2,775	)	$	(2,769	)

Summary of Positions for which Significant Change in Unrecognized Tax Benefits is Reasonably Possible [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	$	59		$	18		$	96
Additions for tax positions of prior years	—			45			1
Reductions for tax positions of prior years	(3		)	(5		)	—
Additions for tax positions of current year	—			1			6
Settlements	(52		)	—			(85		)
Balance at December 31	$	4		$	59		$	18