Accounting Pronouncements (Narrative) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Cost of sales	$ (4,362)	$ (4,691)	$ (5,183)
Selling, General and Administrative Expense	(482)	(483)	(546)
Research and Development Expense	(74)	(67)	(72)
Other (charges) gains, net	(39)	(203)	9
Operating profit (loss)	664	834	1,334
Non-operating pension and other postretirement employee benefit (expense) income	(17)	20	$ 62
Retained earnings	8,091	6,399
Operating lease, liability	244
Operating lease right-of-use assets	$ 232	$ 203