Employee Benefit Plans (Pension Plans) (Level 3 Significant Unobservable Inputs) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Defined Benefit Plan Disclosure [Line Items]
Beginning Balance, Plan Assets	$ 47,960
Ending Balance, Plan Assets	48,945	$ 47,960
Significant Unobservable Inputs (Level 3) [Member]
Defined Benefit Plan Disclosure [Line Items]
Beginning Balance, Plan Assets	1,650	1,885
Realized gains (losses)	(69)	76
Unrealized gains (losses) relating to instruments still held in the reporting period	(134)	64
Purchases, sales and settlements, net	20	(211)
Transfers in/out, net	0	(164)
Ending Balance, Plan Assets	1,467	1,650
Corporate Bonds [Member]
Defined Benefit Plan Disclosure [Line Items]
Beginning Balance, Plan Assets	12,639
Ending Balance, Plan Assets	13,185	12,639
Corporate Bonds [Member] | Significant Unobservable Inputs (Level 3) [Member]
Defined Benefit Plan Disclosure [Line Items]
Beginning Balance, Plan Assets	0
Ending Balance, Plan Assets	0	0
Real Estate [Member]
Defined Benefit Plan Disclosure [Line Items]
Beginning Balance, Plan Assets	3,411
Ending Balance, Plan Assets	3,099	3,411
Real Estate [Member] | Significant Unobservable Inputs (Level 3) [Member]
Defined Benefit Plan Disclosure [Line Items]
Beginning Balance, Plan Assets	1,650
Ending Balance, Plan Assets	$ 1,467	$ 1,650