Regulatory Assets and Liabilities (Tables)

12 Months Ended

Dec. 31, 2025

Regulatory Assets and Liabilities Disclosure [Abstract]

Components of regulatory assets:


(Millions of Dollars)	See Note(s)	Remaining Amortization Period	Dec. 31, 2025				Dec. 31, 2024 (a)
Regulatory Assets			Current		Noncurrent		Current		Noncurrent
Pension and retiree medical obligations	9	Various	$	5	$	150	$	4	$	156
Net AROs (b)	1, 10	Various	—		83		—		70
Recoverable deferred taxes on AFUDC		Plant lives	—		52		—		46
Excess deferred taxes — TCJA	7	Various	1		32		1		45
Losses on reacquired debt		Term of related debt	1		16		1		17


Excess liability insurance costs		Two years	—		14		—		—

Other		Various	17		29		37		25
Total regulatory assets			$	24	$	376	$	43	$	359

(a)Prior period amounts have been reclassified to conform with current year presentation.

(b)Includes amounts recorded for future recovery of AROs.

Regulatory Liabilities

Components of regulatory liabilities:


(Millions of Dollars)	See Note(s)	Remaining Amortization Period	Dec. 31, 2025				Dec. 31, 2024 (a)
Regulatory Liabilities			Current		Noncurrent		Current		Noncurrent
Deferred income tax adjustments and TCJA refunds (b)	7	Various	$	—	$	418	$	—	$	436
Plant removal costs	1, 10	Various	—		283		—		267
LP&L departure payment		Eight years	4		26		4		29



Contract valuation adjustments (c)	1, 8	Less than one year	79		—		67		—
Deferred electric energy costs		Less than one year	20		—		41		—
Other		Various	15		45		30		36
Total regulatory liabilities			$	118	$	772	$	142	$	768

(a)Prior period amounts have been reclassified to conform with current year presentation.

(b)Includes the revaluation of recoverable/regulated plant accumulated deferred income taxes and revaluation impact of non-plant accumulated deferred income taxes due to the TCJA.

(c)Includes the fair value of FTR instruments utilized/intended to offset the impacts of transmission system congestion.