Employee Benefit Plans - Net Benefit Expense Recorded on the Income Statement (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Components of expense/ (income) related to net benefit expense [Abstract]
Total Income Included in Other Income - Net	$ (64)	$ (42)	$ (43)
Pension Benefits
Components of expense/ (income) related to net benefit expense [Abstract]
Service Cost Included in Labor and Fringe	41	43	31
Interest Cost	55	82	103
Expected Return on Plan Assets	(186)	(176)	(171)
Amortization of Net Loss	73	54	30
Amortization of Prior Service Cost	0	0	0
Total Income Included in Other Income - Net	(58)	(40)	(38)
Net Periodic Benefit (Credit)/Cost	(17)	3	(7)
Settlement Gain	0	(1)	0
Total Periodic Benefit (Credit)/Cost	(17)	2	(7)
Post-retirement Benefits
Components of expense/ (income) related to net benefit expense [Abstract]
Service Cost Included in Labor and Fringe	1	1	1
Interest Cost	1	5	2
Expected Return on Plan Assets	0	0	0
Amortization of Net Loss	0	1	0
Amortization of Prior Service Cost	(7)	(7)	(7)
Total Income Included in Other Income - Net	(6)	(1)	(5)
Net Periodic Benefit (Credit)/Cost	(5)	0	(4)
Settlement Gain	0	0	0
Total Periodic Benefit (Credit)/Cost	$ (5)	$ 0	$ (4)