Benefit Plans (Net Periodic Benefit Cost) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
U.S. Defined Benefit Plans
Components of Net Periodic Benefit Cost:
Service cost	$ 13	$ 16	$ 14
Interest cost	42	48	50
Expected return on plan assets	(68)	(70)	(67)
Amortization of prior service cost	7	7	6
Amortization of net loss	18	20	13
Defined Benefit Plan, Recognized Net Gain (Loss) Due to Curtailments	4	0	0
Settlement gain recognized	0	0	0
Total pension cost	16	21	16
Foreign Defined Benefit Plans
Components of Net Periodic Benefit Cost:
Service cost	13	15	16
Interest cost	344	340	473
Expected return on plan assets	(221)	(236)	(348)
Amortization of prior service cost	(1)	0	(1)
Amortization of net loss	19	25	35
Defined Benefit Plan, Recognized Net Gain (Loss) Due to Curtailments	0	0	0
Settlement gain recognized	0	0	1
Total pension cost	$ 154	$ 144	$ 176