Other Comprehensive Income (Tables)

12 Months Ended

Dec. 31, 2024

Stockholders' Equity Note [Abstract]

Changes in Accumulated Other Comprehensive Income (Loss), Net of Tax

Changes in accumulated other comprehensive loss, net of tax, for the years ended Dec. 31:

	2024
(Millions of Dollars)	Gains and Losses on Interest Rate Cash Flow Hedges			Defined Benefit Pension and Postretirement Items			Total
Accumulated other comprehensive loss at Jan. 1	$	(53)		$	(41)		$	(94)
Other comprehensive income (loss) before reclassifications	22			(3)			19
Losses reclassified from net accumulated other comprehensive loss:
Amortization of interest rate hedges	2		(a)	—			2
Amortization of net actuarial loss	—			5		(b)	5
Net current period other comprehensive income	24			2			26
Accumulated other comprehensive loss at Dec. 31	$	(29)		$	(39)		$	(68)

(a)Included in interest charges.

(b)Included in the computation of net periodic pension and postretirement benefit costs. See Note 11 for further information.

	2023
(Millions of Dollars)	Gains and Losses on Interest Rate Cash Flow Hedges			Defined Benefit Pension and Postretirement Items			Total
Accumulated other comprehensive loss at Jan. 1	$	(54)		$	(39)		$	(93)
Other comprehensive loss before reclassifications	(2)			(4)			(6)
Losses reclassified from net accumulated other comprehensive loss:
Amortization of interest rate hedges	3		(a)	—			3
Amortization of net actuarial loss	—			2		(b)	2
Net current period other comprehensive income (loss)	1			(2)			(1)
Accumulated other comprehensive loss at Dec. 31	$	(53)		$	(41)		$	(94)

(a)Included in interest charges.

(b)Included in the computation of net periodic pension and postretirement benefit costs. See Note 11 for further information.