Income Taxes (Tables)

12 Months Ended

Dec. 31, 2011

Income Taxes [Abstract]

Schedule Of Income Tax Expense (Benefit)

	For the Year Ended December 31,
	2011			2010			2009
	(millions of dollars)
Current Tax Expense (Benefit)
Federal	$	9		$	(270	)	$	(160	)
State and local		4			(50	)		(32	)
Total Current Tax Expense (Benefit)		13			(320	)		(192	)
Deferred Tax Expense (Benefit)
Federal		121			300			261
State and local		19			34			39
Investment tax credit amortization		(4	)		(3	)		(4	)
Total Deferred Tax Expense		136			331			296
Total Consolidated Income Tax Expense Related to Continuing Operations	$	149		$	11		$	104

Effective Income Tax Rate From Continuing Operations

	For the Year Ended December 31,
	2011					2010					2009
	(millions of dollars)
Income tax at Federal statutory rate	$	143		35.0	%	$	52		35.0	%	$	114		35.0	%
Increases (decreases) resulting from
Depreciation		—		—			(3	)	(2.0	)%		6		1.8	%
State income taxes, net of Federal effect		22		5.4	%		—		—			19		5.7	%
State tax benefits related to prior years' asset dispositions		(4	)	(1.0	)%		—		—			(13	)	(4.0	)%
Cross-border energy lease investments		16		3.9	%		(5	)	(3.3	)%		(6	)	(1.7	)%
Change in estimates and interest related to uncertain and effectively settled tax positions		(11	)	(2.7	)%		(6	)	(4.0	)%		(1	)	(0.4	)%
Investment tax credits		(4	)	(1.0	)%		(4	)	(2.7	)%		(4	)	(1.2	)%
Deferred tax basis adjustments		2		0.2	%		(3	)	(2.0	)%		(4	)	(1.2	)%
Reversal of valuation allowances		—		—			(8	)	(5.3	)%		—		—
Change in state deferred tax balances as a result of restructuring		—		—			(6	)	(4.0	)%		—		—
Other, net		(15	)	(3.4	)%		(6	)	(4.4	)%		(7	)	(2.2	)%
Consolidated Income Tax Expense Related to Continuing Operations	$	149		36.4	%	$	11		7.3	%	$	104		31.8	%

Reconciliation Of Beginning And Ending Balances Of Unrecognized Tax Benefits

	2011			2010			2009
	(millions of dollars)
Beginning balance as of January 1,	$	395		$	246		$	255
Tax positions related to current year:
Additions		2			150			(1	)
Reductions		—			—			(2	)
Tax positions related to prior years:
Additions		20			35			77
Reductions		(57	)		(36	)		(83	)
Settlements		(3	)		—			—
Ending balance as of December 31,	$	357		$	395		$	246

Components Of Consolidated Deferred Tax Liabilities (Assets)

	At December 31,
	2011			2010
	(millions of dollars)
Deferred Tax Liabilities (Assets)
Depreciation and other basis differences related to plant and equipment	$	1,871		$	1,680
Deferred electric service and electric restructuring liabilities		131			154
Cross-border energy lease investments		793			816
Federal and state net operating losses		(220	)		(46	)
Valuation allowances on state net operating losses		21			21
Pension and other postretirement benefits		130			70
Deferred taxes on amounts to be collected through future rates		47			43
Other		32			(113	)
Total Deferred Tax Liabilities, net		2,805			2,625
Deferred tax assets included in Current Assets		59			90
Deferred tax liabilities included in Other Current Liabilities		(1	)		(1	)
Total Consolidated Deferred Tax Liabilities, net non-current	$	2,863		$	2,714

Other Taxes

	2011		2010		2009
	(millions of dollars)
Gross Receipts/Delivery	$	145	$	145	$	142
Property		71		70		68
County Fuel and Energy		170		154		94
Environmental, Use and Other		65		65		64
Total	$	451	$	434	$	368