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) - Cash Flow Hedges [Member] - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015
Foreign Exchange Forward Contracts [Member]
Derivative [Line Items]
Derivative, notional amount	$ 2,340	$ 2,445
Net unrealized gains (losses) included in accumulated other comprehensive income (loss), net of taxes	39	(12)
Foreign Exchange Forward, Maturity 2016 [Member]
Derivative [Line Items]
Derivative, notional amount	0	1,215
Foreign Exchange Forward, Maturity 2017 [Member]
Derivative [Line Items]
Derivative, notional amount	1,320	900
Foreign Exchange Forward, Maturity 2018 [Member] [Member]
Derivative [Line Items]
Derivative, notional amount	$ 1,020	$ 330