Provision for Income Taxes (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Income Tax Disclosure [Abstract]
Provision for income taxes	$ 230	$ 366	$ 796	$ 723
Tax expense (benefit) associated with the company's policy of hedging the foreign currency-denominated monetary assets and liabilities	(30)	$ 3	182	$ (25)
Tax benefit associated with the reversal of a tax valuation allowance	(26)		(26)
Low end of range estimate of reasonably possible net reduction in unrecognized tax benefits	100		100
High end of range estimate of reasonably possible net reduction in unrecognized tax benefits	$ 125		$ 125