Employee Benefit Plans (Net Periodic Benefit Costs) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
Pension Benefits
Net periodic benefit costs [Abstract]
Service costs	$ 41	$ 37	$ 81	$ 75
Interest costs	114	117	228	235
Expected return on plan assets	(115)	(121)	(230)	(241)
Amortization of net actuarial (gains) losses	41	39	83	78
Amortization of prior service costs (credit)	(3)	(3)	(6)	(6)
Net periodic benefit costs (credit)	78	69	156	141
Other Postretirement Benefits
Net periodic benefit costs [Abstract]
Service costs	1	0	2	1
Interest costs	10	10	20	21
Expected return on plan assets	(14)	(15)	(28)	(28)
Amortization of net actuarial (gains) losses	(6)	(7)	(14)	(15)
Amortization of prior service costs (credit)	0	0	0	0
Net periodic benefit costs (credit)	$ (9)	$ (12)	$ (20)	$ (21)