Aggregate notional amount specified by the derivative(s). Expressed as an absolute value.

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Objectives And Strategies For Using Derivatives (Narratives) (Details) - USD ($)	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017	Dec. 31, 2017
Not Designated as Hedging Instrument
Derivative Instruments, Gain (Loss)
Gain (loss) on undesignated foreign exchange hedging instruments	$ 3,000,000	$ (3,000,000)
Foreign currency exchange contracts \| Not Designated as Hedging Instrument
Derivative Instruments, Gain (Loss)
Aggregate notional values of outstanding derivatives	2,300,000,000
Net Investment Hedging
Derivative Instruments, Gain (Loss)
Aggregate notional values of outstanding derivatives	$ 1,000,000,000
Cash Flow Hedging
Derivative Instruments, Gain (Loss)
Cash flow hedge ineffectiveness assertion	Cash flow hedges resulted in no significant ineffectiveness for the three months ended March 31, 2018 and 2017
Derivative, Maturity Date	Mar. 31, 2020
Cash Flow Hedging \| Foreign currency exchange contracts
Derivative Instruments, Gain (Loss)
Aggregate notional values of outstanding derivatives	$ 764,000,000
Fair Value Hedging
Derivative Instruments, Gain (Loss)
Fair value hedge ineffectiveness assertion	Fair value hedges resulted in no significant ineffectiveness in the three months ended March 31, 2018 and 2017
Gain (loss) recognized in earnings as a result of hedge not qualifying as a fair value hedge	$ 0	$ 0
Fair Value Hedging \| Interest Rate Contract [Member]
Derivative Instruments, Gain (Loss)
Aggregate notional values of outstanding derivatives	300,000,000
Fair Value, Measurements, Recurring [Member] \| Fair Value, Inputs, Level 2
Derivative Instruments, Gain (Loss)
Derivative Asset	30,000,000		$ 27,000,000
Derivative Liability	$ 69,000,000		$ 51,000,000