Employee Benefit Plans (Components of Net Periodic Pension (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	(1,555)	(1,413)	(1,414)
Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	222	470	523
Interest cost	2,507	1,520	1,249
Expected return on plan assets	(3,753)	(3,544)	(3,476)
Amortization of prior service credit	(158)	(163)	(168)
Recognized actuarial net (gain) loss	(378)	305	435
Net settlement, curtailment, and special termination benefits loss	6	2	22
Non-service pension income	(1,776)	(1,880)	(1,938)
Net periodic pension and other postretirement income	$ (1,554)	$ (1,410)	$ (1,415)