Segments and Related Information (Tables)

12 Months Ended

Dec. 31, 2013

Segment Reporting [Abstract]

Results from Continuing Operations by Reportable Segment

(Thousands of Dollars)	Regulated Electric		Regulated Natural Gas		All Other			Reconciling Eliminations			Consolidated Total
2013
Operating revenues (a)	$	3,081,171	$	1,080,703	$	40,754		$	—		$	4,202,628
Intersegment revenues	302		110		—			(412		)	—
Total revenues	$	3,081,473	$	1,080,813	$	40,754		$	(412	)	$	4,202,628
Depreciation and amortization	$	280,972	$	75,510	$	3,935		$	—		$	360,417
Interest charges and financing costs	129,787		30,604		554			—			160,945
Income tax expense (benefit)	220,356		42,294		(11,910		)	—			250,740
Net Income	368,586		69,682		15,115			—			453,383

(Thousands of Dollars)	Regulated Electric		Regulated Natural Gas		All Other			Reconciling Eliminations			Consolidated Total
2012
Operating revenues (a)	$	2,969,899	$	962,435	$	36,959		$	—		$	3,969,293
Intersegment revenues	282		90		—			(372		)	—
Total revenues	$	2,970,181	$	962,525	$	36,959		$	(372	)	$	3,969,293
Depreciation and amortization	$	267,944	$	66,983	$	3,900		$	—		$	338,827
Interest charges and financing costs	145,641		33,430		618			—			179,689
Income tax expense (benefit)	212,347		27,968		(7,771		)	—			232,544
Net income	387,724		60,003		10,349			—			458,076

(Thousands of Dollars)	Regulated Electric		Regulated Natural Gas		All Other			Reconciling Eliminations			Consolidated Total
2011
Operating revenues (a)	$	3,114,370	$	1,087,749	$	38,683		$	—		$	4,240,802
Intersegment revenues	318		242		—			(560		)	—
Total revenues	$	3,114,688	$	1,087,991	$	38,683		$	(560	)	$	4,240,802
Depreciation and amortization	$	265,078	$	59,189	$	4,315		$	—		$	328,582
Interest charges and financing costs	149,291		33,249		939			—			183,479
Income tax expense (benefit)	202,355		30,957		(4,951		)	—			228,361
Net income	334,516		55,446		6,841			—			396,803

^(a)  Operating revenues include $12.6 million, $13.7 million and $15.3 million of intercompany revenue for the years ended Dec. 31, 2013, 2012 and 2011, respectively. See Note 16 for further discussion of related party transactions by reportable segment.