Information about Segments and Geographic Areas (Long-Lived Assets by Geographic Area) (Details) - USD ($) $ in Millions	Mar. 31, 2017	Dec. 31, 2016
Revenues from External Customers and Long-Lived Assets [Line Items]
Long-lived assets	$ 63,962	$ 62,089
United States
Revenues from External Customers and Long-Lived Assets [Line Items]
Long-lived assets	48,468	47,383
International
Revenues from External Customers and Long-Lived Assets [Line Items]
Long-lived assets	$ 15,494	$ 14,706