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

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Entity discloses that the amount of fair value hedge ineffectiveness is immaterial.

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Amount of gain (loss) recognized in earnings in the period from the increase (decrease) in fair value of foreign currency derivatives not designated as hedging instruments.

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Objectives and Strategies for Using Derivatives (Narrative) (Details) - USD ($) $ in Millions	12 Months Ended			36 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2017
Net Investment Hedging
Aggregate notional value	$ 870			$ 870
Fair Value Hedging
Fair value hedge ineffectiveness is immaterial assertion				Fair value hedges resulted in no significant ineffectiveness in each of the three years ended December 31, 2017
Gains or losses from hedged firm commitment not qualifying as fair value hedge				$ 0
Cash Flow Hedging
Cash flow hedge ineffectiveness is immaterial assertion				Cash flow hedges resulted in no significant ineffectiveness in each of the three years ended December 31, 2017
Gains or losses reclassified into earnings resulting from discontinuance of cash flow hedges				$ 0
Maximum maturity of cash flow hedges	Jan. 31, 2020
Foreign Exchange Contract \| Cash Flow Hedging
Aggregate notional value	$ 795			795
Foreign Exchange Contract \| Not Designated as Hedging Instrument
Aggregate notional value	2,400			2,400
Gains (Losses) on undesignated foreign exchange hedging instruments	37	$ (30)	$ (188)
Interest Rate Contract \| Fair Value Hedging
Aggregate notional value	300			300
Interest Rate Contract \| Cash Flow Hedging
Aggregate notional value	200			200
Fair Value, Measurements, Recurring \| Fair Value, Inputs, Level 2
Derivative Asset	27	43		27
Derivative Liability	$ 51	$ 46		$ 51