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) - Designated as Hedging Instrument [Member] - Cash Flow Hedging [Member] - USD ($) $ in Millions	Jun. 30, 2021	Dec. 31, 2020
Foreign Exchange Contract
Derivative [Line Items]
Derivative, Notional Amount	$ 2,238	$ 2,273
Foreign Exchange Contract, Maturity 2021 [Member]
Derivative [Line Items]
Derivative, Notional Amount	815	1,470
Foreign Exchange Contract, Maturity 2022
Derivative [Line Items]
Derivative, Notional Amount	1,098	803
Foreign Exchange Contract, Maturity 2023
Derivative [Line Items]
Derivative, Notional Amount	325	0
Foreign Exchange Option [Member]
Derivative [Line Items]
Derivative, Notional Amount	$ 128	$ 133