Financial Instruments (Effects of Derivatives on Earnings) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Derivative Instruments and Hedging Activities [Line Items]
Total effect on earnings	$ (380)	$ (35)	$ (810)	$ (270)
Cash Flow Hedges [Member]
Derivative Instruments and Hedging Activities [Line Items]
Effect on hedging instrument	2	(123)	(43)	(760)
Effect on underlying	(2)	124	43	761
Effect on earnings (Cash flow hedges)	0	1	0	1
Fair Value Hedges [Member]
Derivative Instruments and Hedging Activities [Line Items]
Effect on hedging instrument	(116)	1,383	2,494	510
Effect on underlying (Fair value hedges)	37	(1,379)	(2,651)	(590)
Effect on earnings (Fair value hedges)	(79)	4	(156)	(80)
Net Investment Hedges [Member]
Derivative Instruments and Hedging Activities [Line Items]
Effect on hedging instrument	557	1,260	484	4,627
Effect on underlying	(552)	(1,297)	(513)	(4,720)
Effect on earnings (Net investment hedges)	5	(37)	(28)	(93)
Economic Hedges [Member]
Derivative Instruments and Hedging Activities [Line Items]
Effect on hedging instrument	(692)	(486)	(835)	(2,729)
Effect on underlying (Economic hedges)	386	483	209	2,631
Total effect on earnings	$ (306)	$ (3)	$ (626)	$ (98)