Change in Accounting Principles (Details) $ / shares in Units, $ in Millions	3 Months Ended	6 Months Ended
	Jun. 30, 2015 USD ($) $ / shares	Jun. 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	$ 12,384	$ 12,384		$ 11,930
Retained earnings	33,544	33,544		$ 31,849
Inventory valuation methodology adjustment [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Inventories			$ (7)
Current deferred tax asset			3
Retained earnings			$ 4
Effect of change on net income	$ 12	$ 8
New Accounting Pronouncement or Change in Accounting Principle, Effect of Change on Basic Earnings Per Share | $ / shares	$ 0.01	$ 0.00
New Accounting Pronouncement or Change in Accounting Principle, Effect of Change on Diluted Earnings Per Share | $ / shares	$ 0.01	$ 0.01