Employee Benefit Plans (Components of Net Periodic PRB (Income) Expense) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Defined Benefit Plan Disclosure [Line Items]
Non-service pension income	$ (1,780)	$ (1,889)	$ (1,944)
Net periodic pension and other postretirement (income) expense	(1,555)	(1,413)	(1,414)
Other Postretirement Benefits Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	3	6	7
Interest cost	50	29	24
Expected return on plan assets	(20)	(22)	(21)
Amortization of prior service credit	(1)	(2)	(3)
Recognized actuarial net (gain) loss	(31)	(11)	(6)
Net settlement, curtailment, and special termination benefits loss	(2)	(3)	0
Non-service pension income	(4)	(9)	(6)
Net periodic pension and other postretirement (income) expense	$ (1)	$ (3)	$ 1