Income Taxes (Tables)

6 Months Ended

Jun. 30, 2011

Income Taxes

Effective Income Tax Rate From Continuing Operations

	Three Months Ended June 30,										Six Months Ended June 30,
	2011					2010					2011					2010
	(millions of dollars)
Income tax at federal statutory rate	$	52		35.0	%	$	38		35.0	%	$	86		35.0	%	$	57		35.0	%
Increases (decreases) resulting from:
State income taxes, net of federal effect		6		4.0			5		5.0			11		4.5			9		5.6
Depreciation		—		—			2		1.4			(1	)	(0.4	)		3		1.7
Cross-border energy lease investments		21		14.1			(1	)	(1.2	)		20		8.2			(2	)	(1.5	)
Change in estimates and interest related to uncertain and effectively settled tax positions		(17	)	(11.4	)		1		1.0			(15	)	(6.1	)		10		6.2
Tax credits		(1	)	(0.7	)		(1	)	(0.9	)		(2	)	(0.8	)		(2	)	(1.2	)
Medicare Part D subsidy		—		—			—		—			—		—			4		2.2
Release of valuation allowance		—		—			—		—			—		—			(8	)	(4.8	)
Change in state deferred tax balances as a result of corporate restructuring		—		—			(8	)	(7.8	)		—		—			(8	)	(5.2	)
State tax benefit related to prior years' asset dispositions		(4	)	(2.7	)		—		—			(4	)	(1.6	)		—		—
Other, net		(3	)	(2.1	)		(3	)	(2.2	)		(7	)	(2.9	)		(5	)	(2.2	)
Consolidated income tax expense related to continuing operations	$	54		36.2	%	$	33		30.3	%	$	88		35.9	%	$	58		35.8	%