Employee Benefit Plans (Net Periodic Benefit Costs) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Pension Benefits
Net periodic benefit costs [Abstract]
Service costs	$ 37	$ 50	$ 75	$ 102
Interest costs	117	82	235	163
Expected return on plan assets	(121)	(129)	(241)	(258)
Amortization of net actuarial (gains) losses	39	30	78	61
Amortization of prior service costs (credit)	(3)	(3)	(6)	(6)
Net periodic benefit costs (credit)	69	30	141	62
Other Postretirement Benefits
Net periodic benefit costs [Abstract]
Service costs	0	1	1	2
Interest costs	10	9	21	17
Expected return on plan assets	(15)	(15)	(28)	(28)
Amortization of net actuarial (gains) losses	(7)	(6)	(15)	(12)
Amortization of prior service costs (credit)	0	0	0	0
Net periodic benefit costs (credit)	$ (12)	$ (11)	$ (21)	$ (21)