Other Income - Net (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019		Dec. 31, 2018
Other Income and Expenses [Abstract]
Net Periodic Pension and Post-retirement Benefit Credit	$ 42	$ 43		$ 38
Interest Income	17	48		32
Debt Repurchase Expense	(48)	(10)		0
Miscellaneous Income	8	7		4
Total Other Income - Net	$ 19	$ 88	[1]	$ 74	[1]

[1] Certain prior year data has been reclassified to conform to the current presentation.