Borrowings and Other Financing Instruments (Tables)

6 Months Ended

Jun. 30, 2025

Borrowings and Other Financing Instruments [Abstract]

Credit Facilities

As of June 30, 2025, SPS had the following committed revolving credit facility available (in millions of dollars):

Credit Facility (a)		Drawn (b)		Available
$	600	$	—	$	600

(a)Expires in December 2029.

(b)Includes outstanding letters of credit.

Money Pool

Borrowings and Other Financing Instruments [Abstract]

Short-Term Borrowings

Money pool borrowings:

(Amounts in Millions, Except Interest Rates)	Three Months Ended June 30, 2025			Year Ended Dec. 31, 2024
Borrowing limit	$	100		$	100
Amount outstanding at period end	—			7
Average amount outstanding	29			24
Maximum amount outstanding	100			100
Weighted average interest rate, computed on a daily basis	4.33		%	5.29		%
Weighted average interest rate at period end	N/A			4.58

Commercial Paper

Borrowings and Other Financing Instruments [Abstract]

Short-Term Borrowings

Commercial paper outstanding:

(Amounts in Millions, Except Interest Rates)	Three Months Ended June 30, 2025			Year Ended Dec. 31, 2024
Borrowing limit	$	600		$	500
Amount outstanding at period end	—			145
Average amount outstanding	86			35
Maximum amount outstanding	260			160
Weighted average interest rate, computed on a daily basis	4.65		%	5.47		%
Weighted average interest rate at period end	N/A			4.66