Retirement Benefits Unamortized Prior Service Credit Rollforward (Details 2) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2025	Dec. 31, 2024	Dec. 31, 2023
Amortization of:
Prior service credit	$ 3	$ 0	$ 1
(Increase) decrease in prior service credit		12
Tax expense (benefit) related to above items	(1)	3	0
Change in unamortized benefit plan costs	2	(9)	1
Pension Benefits
Amortization of:
Prior service credit	0	0	0
(Increase) decrease in prior service credit		0
Tax expense (benefit) related to above items	0	0	0
Change in unamortized benefit plan costs	0	0	0
Medical and Life Benefits
Amortization of:
Prior service credit	3	0	1
(Increase) decrease in prior service credit		12
Tax expense (benefit) related to above items	(1)	3	0
Change in unamortized benefit plan costs	$ 2	$ (9)	$ 1