Debt (Schedule Of Changes In Debt) (Details) - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019
Debt Instrument [Line Items]
Balance as of beginning-of-year	$ 6,367
Notes issued	1,289	$ 495
Repayment of notes	(1,096)	$ (108)
Unamortized premiums (discounts)	(1)
Unamortized debt issuance costs	(6)
Unamortized adjustments from discontinued hedges	256
Fair value hedge on interest rate swap agreements	(106)
Balance as of end-of-period	6,714
3.40% notes Due 2031 [Member]
Debt Instrument [Line Items]
Notes issued	$ 500
Interest rate	3.40%
4.375% Notes Due 2050 [Member]
Debt Instrument [Line Items]
Notes issued	$ 300
Interest rate	4.375%
6.25% Senior Notes, Due 2020 [Member]
Debt Instrument [Line Items]
Repayment of notes	$ (300)
Interest rate	6.25%
4.85% Notes, Due 2021 [Member]
Debt Instrument [Line Items]
Repayment of notes	$ (296)
Interest rate	4.85%
LIBOR + 150 bps Term Loan Issued, Due 2022 [Member]
Debt Instrument [Line Items]
Notes issued	$ 500
Repayment of notes	$ (500)
LIBOR + 150 bps Term Loan Issued, Due 2022 [Member] | London Interbank Offered Rate (LIBOR) [Member]
Debt Instrument [Line Items]
Variable rate	1.50%