Retirement Plans (Narrative) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022	Dec. 31, 2022
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Capitalization of pension and OPEB expense	$ 4	$ 6
OPEB Remeasurement	(20)	$ 54
Pension [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Contributions to plans	30
Increase in plan assets	95
Plan assets	2,128		$ 2,033
Investment returns	110
Benefit payments	45
OPEB [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Medical coverage, remeasurement losses	$ 20