Borrowings and Other Financing Instruments (Tables)

12 Months Ended

Dec. 31, 2012

Long-Term Borrowings and Other Financing Instruments [Abstract]

Committed Credit Facility Available

At Dec. 31, 2012, SPS had the following committed credit facility available (in millions):

Credit Facility		Drawn (a)		Available
$	300.0	$	9.0	$	291.0

(a) Includes outstanding commercial paper.

Money Pool [Member]

Long-Term Borrowings and Other Financing Instruments [Abstract]

Short-Term Borrowings

Money Pool — Xcel Energy Inc. and its utility subsidiaries have established a money pool arrangement that allows for short-term investments in and borrowings between the utility subsidiaries. Xcel Energy Inc. may make investments in the utility subsidiaries at market-based interest rates; however, the utility money pool arrangement does not allow the utility subsidiaries to make investments in Xcel Energy Inc. The following tables present the money pool borrowings for SPS:

(Amounts in Millions, Except Interest Rates)	Three Months Ended Dec. 31, 2012
Borrowing limit	$	100
Amount outstandingat period end		-
Average amount outstanding		1
Maximum amount outstanding		9
Weighted average interest rate, computed on a daily basis		0.34	%
Weighted average interest rate at end of period		N/A

(Amounts in Millions, Except Interest Rates)	Twelve Months Ended Dec. 31, 2012			Twelve Months Ended Dec. 31, 2011			Twelve Months Ended Dec. 31, 2010
Borrowing limit	$	100		$	100		$	100
Amount outstandingat period end		-			5			-
Average amount outstanding		10			12			16
Maximum amount outstanding		63			71			77
Weighted average interest rate, computed on a daily basis		0.33	%		0.35	%		0.37	%
Weighted average interest rate at end of period		N/A			0.35			N/A

Commercial Paper [Member]

Long-Term Borrowings and Other Financing Instruments [Abstract]

Short-Term Borrowings

Commercial Paper — SPS meets its short-term liquidity requirements primarily through the issuance of commercial paper and borrowings under its credit facility. The following tables present commercial paper outstanding for SPS:

(Amounts in Millions, Except Interest Rates)	Three Months Ended Dec. 31, 2012
Borrowing limit	$	300
Amount outstandingat period end		9
Average amount outstanding		4
Maximum amount outstanding		28
Weighted average interest rate, computed on a daily basis		0.34	%
Weighted average interest rate at end of period		0.36

(Amounts in Millions, Except Interest Rates)	Twelve Months Ended Dec. 31, 2012		Twelve Months Ended Dec. 31, 2011			Twelve Months Ended Dec. 31, 2010
Borrowing limit	$	300	$	300		$	248
Amount outstandingat period end		9		-			49
Average amount outstanding		18		54			8
Maximum amount outstanding		106		161			65
Weighted average interest rate, computed on a daily basis		0.39		0.37	%		0.37	%
Weighted average interest rate at end of period		0.36		N/A			0.37