Benefit Plans - Schedule of Accrued Benefit Obligation Recorded in Accumulated Other Comprehensive Income (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2025	Dec. 31, 2024	Dec. 31, 2023
Deferred Income Tax Expense
Changes	$ 13	$ (11)	$ (7)
Postretirement Benefit Plan
Net Actuarial Gain
Beginning balance	40	44
Changes	(4)	(4)
Ending balance	36	40	44
Deferred Income Tax Expense
Beginning balance	9	10
Changes	1	1
Ending balance	8	9	10
Accumulated Other Comprehensive Income
Beginning balance	31	34
Changes	(3)	(3)
Ending balance	$ 28	$ 31	$ 34