Accounting Policies - Reclassifications and Adjustments (Details) - USD ($) $ in Millions	3 Months Ended			9 Months Ended
	Sep. 30, 2016	Jun. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Cost of goods sold	$ 2,736		$ 3,000	$ 8,250	$ 9,093
Scenario, Adjustment
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Cost of goods sold		$ 24