Long-Term Debt (Schedule Of Changes In Long Term Debt) (Details) - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018
Debt Instrument [Line Items]
Balance as of beginning-of-year	$ 5,839
Notes issued	495	$ 1,094
Early extinguishment of notes	(108)	$ (537)
Reclassification of long-term debt to current maturities	(300)
Unamortized debt issuance costs	(1)
Unamortized adjustments from discontinued hedges	(4)
Fair value hedge-interest rate swap	145
Balance as of end-of-period	6,070
3.05% Notes, Due 2030 [Member]
Debt Instrument [Line Items]
Notes issued	$ 500
Interest rate	3.05%
4.85% Notes, Due 2021 [Member]
Debt Instrument [Line Items]
Early extinguishment of notes	$ (4)
Interest rate	4.85%
6.15% Notes, Due 2036 [Member]
Debt Instrument [Line Items]
Early extinguishment of notes	$ (105)
Interest rate	6.15%