Segment Information (Tables)

3 Months Ended

Mar. 31, 2016

Segment Reporting [Abstract]

Results from Operations by Reportable Segment

(Thousands of Dollars)	Regulated Electric		Regulated Natural Gas		All Other		Reconciling Eliminations			Consolidated Total
Three Months Ended March 31, 2016
Operating revenues (a)(b)	$	1,033,643	$	194,130	$	6,860	$	—		$	1,234,633
Intersegment revenues	145		162		—		(307		)	—
Total revenues	$	1,033,788	$	194,292	$	6,860	$	(307	)	$	1,234,633
Net income	$	71,321	$	23,142	$	166	$	—		$	94,629

(Thousands of Dollars)	Regulated Electric				Regulated Natural Gas		All Other			Reconciling Eliminations			Consolidated Total
Three Months Ended March 31, 2015
Operating revenues (a)(b)	$	1,006,154			$	279,467	$	6,861		$	—		$	1,292,482
Intersegment revenues	133				410		—			(543		)	—
Total revenues	$	1,006,287			$	279,877	$	6,861		$	(543	)	$	1,292,482
Net income (loss)	$	(29,599	)	(c)	$	40,272	$	(3,749	)	$	—		$	6,924

^(a)  Operating revenues include $125 million of affiliate electric revenue for the three months ended March 31, 2016 and 2015.

^(b)  Operating revenues include an immaterial amount of affiliate gas revenue for the three months ended March 31, 2016 and 2015.

^(c)  Includes a net of tax charge related to the Monticello LCM/EPU project.  See Note 5.