Regulatory Assets and Liabilities (Tables)

12 Months Ended

Dec. 31, 2024

Regulatory Assets and Liabilities Disclosure [Abstract]

Regulatory Assets

Components of regulatory assets:

(Millions of Dollars)	See Note(s)	Remaining Amortization Period	Dec. 31, 2024				Dec. 31, 2023
Regulatory Assets			Current		Noncurrent		Current		Noncurrent
Pension and retiree medical obligations	9	Various	$	4	$	156	$	2	$	147
Net AROs (a)	1, 10	Various	—		70		—		59
Recoverable deferred taxes on AFUDC		Plant lives	—		46		—		44
Excess deferred taxes — TCJA	7	Various	1		45		1		47
Losses on reacquired debt		Term of related debt	1		17		1		18
Texas revenue surcharges		Less than one year	30		—		21		—
Other		Various	7		25		5		34
Total regulatory assets			$	43	$	359	$	30	$	349

(a)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, 2024				Dec. 31, 2023
Regulatory Liabilities			Current		Noncurrent		Current		Noncurrent
Deferred income tax adjustments and TCJA refunds (a)	7	Various	$	—	$	436	$	—	$	458
Plant removal costs	1, 10	Various	—		267		—		223
LP&L departure payment		Various	4		29		33		33
Effects of regulation on employee benefit costs		Various	—		18		—		19
Formula rates		One to two years	16		2		13		10
Contract valuation adjustments (b)	1, 8	Less than one year	67		—		41		—
Deferred electric energy costs		Less than one year	41		—		15		—
Other		Various	14		16		14		18
Total regulatory liabilities			$	142	$	768	$	116	$	761

(a)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.

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