Accounts Receivable and Inventory - Narrative (Details) - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015
Accounts Receivable and Inventory [Abstract]
Allowance for doubtful accounts receivable	$ 50
Percentage of inventory at FIFO accounted for using the LIFO method (percentage)	44.00%	43.00%
Inventory Disclosure [Abstract]
Raw materials	$ 880	$ 885
Work-in-process	396	412
Finished goods	1,074	1,131
Inventory at FIFO	2,350	2,428
Excess of FIFO over LIFO cost	(96)	(105)
Total inventory	$ 2,254	$ 2,323