Benefit Plans (Net Periodic Benefit Cost) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
U.S. Defined Benefit Plans
Components of Net Periodic Benefit Cost:
Service cost	$ 16	$ 14	$ 16
Interest cost	48	50	46
Expected return on plan assets	(70)	(67)	(64)
Amortization of prior service cost	7	6	5
Amortization of net loss	20	13	23
Settlement gain recognized	0	0	0
Total pension cost	21	16	26
Foreign Defined Benefit Plans
Components of Net Periodic Benefit Cost:
Service cost	15	16	26
Interest cost	351	489	515
Expected return on plan assets	(247)	(362)	(484)
Amortization of prior service cost	0	(1)	0
Amortization of net loss	28	37	77
Settlement gain recognized	0	(1)	0
Total pension cost	$ 147	$ 180	$ 134