Segment Information

3 Months Ended

Mar. 31, 2013

Segment Information [Abstract]

Segment Information

10.  Segment Information

Operating results from the regulated electric utility and regulated natural gas utility are each separately and regularly reviewed by PSCo's chief operating decision maker. PSCo evaluates performance based on profit or loss generated from the product or service provided. These segments are managed separately because the revenue streams are dependent upon regulated rate recovery, which is separately determined for each segment.

PSCo has the following reportable segments: regulated electric utility, regulated natural gas utility and all other.

• PSCo's regulated electric utility segment generates electricity which is transmitted and distributed in Colorado. In addition, this segment includes sales for resale and provides wholesale transmission service to various entities in the United States. Regulated electric utility also includes PSCo's commodity trading operations.

• PSCo's regulated natural gas utility segment transports, stores and distributes natural gas in portions of Colorado.

• Revenues from operating segments not included above are below the necessary quantitative thresholds and are therefore included in the all other category. Those primarily include steam revenue, appliance repair services and nonutility real estate activities.

Asset and capital expenditure information is not provided for PSCo's reportable segments because as an integrated electric and natural gas utility, PSCo operates significant assets that are not dedicated to a specific business segment, and reporting assets and capital expenditures by business segment would require arbitrary and potentially misleading allocations which may not necessarily reflect the assets that would be required for the operation of the business segments on a stand-alone basis.

To report income from continuing operations for regulated electric and regulated natural gas utility segments, the majority of costs are directly assigned to each segment. However, some costs, such as common depreciation, common O&M expenses and interest expense are allocated based on cost causation allocators. A general allocator is used for certain general and administrative expenses, including office supplies, rent, property insurance and general advertising.

	Regulated		Regulated			All			Reconciling				Consolidated
(Thousands of Dollars)	Electric			Natural Gas			Other			Eliminations				Total
Three Months Ended March 31, 2013
Operating revenues from external customers	$	721,348		$	383,924		$	12,185		$	-			$	1,117,457
Intersegment revenues		88			47			-			(135	)			-
Total revenues	$	721,436		$	383,971		$	12,185		$	(135	)		$	1,117,457
Net income	$	78,468		$	33,799		$	4,338		$	-			$	116,605

	Regulated		Regulated			All			Reconciling				Consolidated
(Thousands of Dollars)	Electric			Natural Gas			Other			Eliminations				Total
Three Months Ended March 31, 2012
Operating revenues from external customers	$	682,279		$	383,004		$	10,769		$	-			$	1,076,052
Intersegment revenues		92			55			-			(147	)			-
Total revenues	$	682,371		$	383,059		$	10,769		$	(147	)		$	1,076,052
Net income	$	61,333		$	28,310		$	3,642		$	-			$	93,285