Derivative Financial Instruments (Notional Value Of Outstanding Cash Flow Hedge Contracts By Year Of Maturity And Net Unrealized (Loss) Gain Included In Accumulated Other Comprehensive Income) (Details) - USD ($) $ in Millions	Mar. 31, 2020	Dec. 31, 2019
Foreign Exchange Forward [Member]
Derivative [Line Items]
Net unrealized (losses) gains included in accumulated other comprehensive income (loss), net of taxes		$ 26
Foreign Exchange Forward [Member] | Cash Flow Hedging [Member]
Derivative [Line Items]
Net unrealized (losses) gains included in accumulated other comprehensive income (loss), net of taxes	$ (65)
Designated as Hedging Instrument [Member] | Foreign Exchange Forward [Member] | Cash Flow Hedging [Member]
Derivative [Line Items]
Derivative, Notional Amount	2,340	2,388
Designated as Hedging Instrument [Member] | Foreign Exchange Forward, Maturity 2020 [Member] | Cash Flow Hedging [Member]
Derivative [Line Items]
Derivative, Notional Amount	1,190	1,505
Designated as Hedging Instrument [Member] | Foreign Exchange Forward, Maturity 2021 [Member] | Cash Flow Hedging [Member]
Derivative [Line Items]
Derivative, Notional Amount	1,005	883
Designated as Hedging Instrument [Member] | Foreign Exchange Forward, Maturity 2022 | Cash Flow Hedging [Member]
Derivative [Line Items]
Derivative, Notional Amount	$ 145	$ 0