Debt And Lines Of Credit (Summary of Long-Term Debt Footnotes) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Debt Instrument [Line Items]
Long-term debt, fair value	$ 10,500	$ 10,900
Variable Rate Debt [Member]
Debt Instrument [Line Items]
Long-term Debt, Weighted Average Interest Rate, at Point in Time	1.30%	3.10%
Environmental and industrial development bonds – due 2022 – 2035 (b)
Debt Instrument [Line Items]
Long-term Debt, Weighted Average Interest Rate, at Point in Time	3.50%	4.40%
Other (c)
Debt Instrument [Line Items]
Fair Value, Debt Instrument, Valuation Techniques, Change in Technique, Quantification of Effect	$ 4	$ 7