Information about Segments and Geographic Areas (Long-Lived Assets by Geographic Area) (Details) - USD ($) $ in Millions	Mar. 31, 2020	Dec. 31, 2019
Revenues from External Customers and Long-Lived Assets [Line Items]
Long-lived assets	$ 126,385	$ 123,331
United States
Revenues from External Customers and Long-Lived Assets [Line Items]
Long-lived assets	96,216	94,907
International
Revenues from External Customers and Long-Lived Assets [Line Items]
Long-lived assets	$ 30,169	$ 28,424