Information about Segments and Geographic Areas (Long-Lived Assets by Geographic Area) (Details) - USD ($) $ in Millions	Sep. 30, 2015	Dec. 31, 2014
Revenues from External Customers and Long-Lived Assets [Line Items]
Long-lived assets	$ 56,178	$ 50,448
United States
Revenues from External Customers and Long-Lived Assets [Line Items]
Long-lived assets	42,761	37,355
International
Revenues from External Customers and Long-Lived Assets [Line Items]
Long-lived assets	$ 13,417	$ 13,093