Derivative Financial Instruments (Location And Fair Values Of Derivative Financial Instruments In Our Consolidated Statement Of Financial Position) (Details) - USD ($) $ in Millions	Mar. 31, 2019	Dec. 31, 2018
Derivatives, Fair Value [Line Items]
Derivative assets fair value	$ 55	$ 27
Derivative liabilities fair value	17	34
Cash Flow Hedging [Member] | Designated as Hedging Instrument [Member] | Foreign Exchange Forward [Member]
Derivatives, Fair Value [Line Items]
Derivative assets fair value	52	26
Derivative liabilities fair value	13	30
Cash Flow Hedging [Member] | Designated as Hedging Instrument [Member] | Foreign Exchange Forward [Member] | Other Current Assets [Member]
Derivatives, Fair Value [Line Items]
Derivative assets fair value	22	11
Cash Flow Hedging [Member] | Designated as Hedging Instrument [Member] | Foreign Exchange Forward [Member] | Other Noncurrent Assets [Member]
Derivatives, Fair Value [Line Items]
Derivative assets fair value	30	15
Cash Flow Hedging [Member] | Designated as Hedging Instrument [Member] | Foreign Exchange Forward [Member] | Accrued Expenses And Other Current Liabilities [Member]
Derivatives, Fair Value [Line Items]
Derivative liabilities fair value	12	21
Cash Flow Hedging [Member] | Designated as Hedging Instrument [Member] | Foreign Exchange Forward [Member] | Other Noncurrent Liabilities [Member]
Derivatives, Fair Value [Line Items]
Derivative liabilities fair value	1	9
Other Derivatives [Member] | Not Designated as Hedging Instrument [Member] | Foreign Exchange Forward [Member]
Derivatives, Fair Value [Line Items]
Derivative assets fair value	3	1
Derivative liabilities fair value	4	4
Other Derivatives [Member] | Not Designated as Hedging Instrument [Member] | Foreign Exchange Forward [Member] | Other Current Assets [Member]
Derivatives, Fair Value [Line Items]
Derivative assets fair value	3	1
Other Derivatives [Member] | Not Designated as Hedging Instrument [Member] | Foreign Exchange Forward [Member] | Accrued Expenses And Other Current Liabilities [Member]
Derivatives, Fair Value [Line Items]
Derivative liabilities fair value	$ 4	$ 4