Segment Information (Tables)

9 Months Ended

Sep. 30, 2012

Segment Information [Abstract]

Results from Continuing Operations by Reportable Segment

	Regulated		Regulated			All		Reconciling			Consolidated
(Thousands of Dollars)	Electric		Natural Gas			Other		Eliminations			Total
Three Months Ended Sept. 30, 2012
Operating revenues from external customers	$	870,975	$	113,230		$	8,082	$	-		$	992,287
Intersegment revenues		63		(19	)		-		(44	)		-
Total revenues	$	871,038	$	113,211		$	8,082	$	(44	)	$	992,287
Net income	$	181,743	$	6,366		$	4,334	$	-		$	192,443

	Regulated		Regulated			All		Reconciling			Consolidated
(Thousands of Dollars)	Electric		Natural Gas			Other		Eliminations			Total
Three Months Ended Sept. 30, 2011
Operating revenues from external customers	$	933,490	$	122,672		$	7,772	$	-		$	1,063,934
Intersegment revenues		53		(18	)		-		(35	)		-
Total revenues	$	933,543	$	122,654		$	7,772	$	(35	)	$	1,063,934
Net income (loss)	$	143,702	$	(4,219	)	$	1,235	$	-		$	140,718

	Regulated		Regulated		All		Reconciling			Consolidated
(Thousands of Dollars)	Electric		Natural Gas		Other		Eliminations			Total
Nine Months Ended Sept. 30, 2012
Operating revenues from external customers	$	2,267,905	$	643,632	$	26,303	$	-		$	2,937,840
Intersegment revenues		198		55		-		(253	)		-
Total revenues	$	2,268,103	$	643,687	$	26,303	$	(253	)	$	2,937,840
Net income	$	331,883	$	40,205	$	9,047	$	-		$	381,135

	Regulated		Regulated		All		Reconciling			Consolidated
(Thousands of Dollars)	Electric		Natural Gas		Other		Eliminations			Total
Nine Months Ended Sept. 30, 2011
Operating revenues from external customers	$	2,387,434	$	725,593	$	28,454	$	-		$	3,141,481
Intersegment revenues		237		201		-		(438	)		-
Total revenues	$	2,387,671	$	725,794	$	28,454	$	(438	)	$	3,141,481
Net income	$	276,218	$	27,320	$	4,828	$	-		$	308,366