Employee Benefit Plans - Components of Net Periodic Benefit Costs (Details) - Pension Benefits Cost - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Components of expense/ (income) related to net benefit expense:
Service Cost Included in Labor and Fringe	$ 6	$ 8	$ 18	$ 24
Interest Cost	28	16	84	48
Expected Return on Plan Assets	(41)	(47)	(123)	(141)
Amortization of Net Loss	7	12	21	37
Total Included in Other Income - Net	(6)	(19)	(18)	(56)
Net Periodic Benefit Credit	$ 0	$ (11)	$ 0	$ (32)