Debt And Lines Of Credit Debt and Lines of Credit (Debt Extinguishment Footnotes) (Details) - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Extinguishment of Debt [Line Items]
Extinguishment of Debt, Amount	[1]	$ 780	$ 993	$ 266
Debt Instrument, Maturity Date Range, Start		Jun. 15, 2018	Jun. 15, 2018	Jun. 15, 2018
Debt Instrument, Maturity Date Range, End		Sep. 01, 2032	Sep. 01, 2032	Sep. 01, 2032
Minimum [Member]
Extinguishment of Debt [Line Items]
Debt Instrument, Interest Rate, Stated Percentage		1.57%	1.57%	1.57%
Maximum [Member]
Extinguishment of Debt [Line Items]
Debt Instrument, Interest Rate, Stated Percentage		9.38%	9.38%	9.38%

[1] Reductions related to notes with interest rates ranging from 1.57% to 9.38% with original maturities from 2018 to 2032 for the years ended December 31, 2018, 2017 and 2016.