Change in Accounting Principles (Details) $ / shares in Units, $ in Millions	3 Months Ended	9 Months Ended
	Sep. 30, 2015 USD ($) $ / shares	Sep. 30, 2015 USD ($) $ / shares	Jan. 01, 2015 USD ($)	Dec. 31, 2014 USD ($)
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Percentage of consolidated inventories impacted by change in accounting principle			0.36
Inventories	$ 13,282	$ 13,282		$ 11,930
Retained earnings	$ 34,398	$ 34,398		$ 31,849
Inventory valuation methodology adjustment [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
New Accounting Pronouncement or Change in Accounting Principle, Effect of Change on Basic Earnings Per Share | $ / shares	$ 0.00	$ 0.00
Inventories			$ (7)
Current deferred tax asset			3
Retained earnings			$ 4
Effect of change on net income	$ 2	$ 10
New Accounting Pronouncement or Change in Accounting Principle, Effect of Change on Diluted Earnings Per Share | $ / shares	$ 0.00	$ 0.01