Retirement Plans (Net Periodic Benefit Cost) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2025	Jun. 30, 2024	Jun. 30, 2025	Jun. 30, 2024
Defined Benefit Plan Disclosure [Line Items]
Pension remeasurement gain	$ (44)	$ 72	$ (44)	$ (2)
OPEB remeasurement (gain) loss	0	(18)	8	(27)
Pension [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	11	11	22	23
Interest cost on projected benefit obligation	32	33	64	63
Expected return on plan assets	(38)	(42)	(76)	(84)
Pension remeasurement gain		72	(44)	(2)
Net periodic pension (benefit) costs	5	74	(34)
Pension special termination benefit enhancements		4		10
Total pension periodic postretirement (benefit) cost	5	78	(34)	10
OPEB [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	1	2	2	3
Interest cost on projected benefit obligation	7	8	14	15
Amortization of prior service credit gain recognized	(6)	(7)	(12)	(13)
OPEB remeasurement (gain) loss		(18)	8	(27)
Total pension periodic postretirement (benefit) cost	$ 2	$ (15)	$ 12	$ (22)