Condensed Consolidated Statements of Comprehensive Income (unaudited) - USD ($) $ in Millions		3 Months Ended		9 Months Ended
		Sep. 30, 2025	Sep. 30, 2024	Sep. 30, 2025	Sep. 30, 2024
Statement of Comprehensive Income [Abstract]
Net income		$ 64	$ 345	$ 351	$ 343
Other comprehensive income (loss):
Recognition of net actuarial loss due to settlement		1	0	1	0
Actuarial gain associated with pension and postretirement plans, net of tax	[1]	0	9	(1)	9
Amortization of prior service cost credit included in net periodic benefit cost, net of tax	[1]	(1)	(4)	(3)	(6)
Comprehensive income		$ 64	$ 350	$ 348	$ 346

[1] (a) Tax effects of the actuarial gain associated with pension and postretirement plans and amortization of prior service cost credit were insignificant for the three and nine months ended September 30, 2025 and 2024.