Hedging Activities (Narrative) (Details) - USD ($) $ in Millions	Jun. 30, 2017	Dec. 31, 2016
Derivative Asset, Notional Amount	$ 15,935	$ 18,609
Gross Notional Value, Translated Earnings Contracts [Member]
Derivative Asset, Notional Amount	14,300	16,700
Gross Notional Value, Collar Options [Member]
Derivative Asset, Notional Amount	1,200	2,000
Gross Notional Value, Foreign Exchange Forward [Member]
Derivative Asset, Notional Amount	13,100	14,700
Gross Notional Value, Foreign Exchange Forward [Member] | Not Designated as Hedging Instrument [Member]
Derivative Asset, Notional Amount	12,100	13,600
Net Notional Value, Collar Options [Member]
Derivative Asset, Notional Amount	$ 600	$ 1,000