v3.10.0.1
Segment, Geographic and Other Revenue Information - Revenues By Geographic Area - Footnotes (Detail) - USD ($)
$ in Millions
 12 Months Ended
Dec. 31, 2018
Dec. 31, 2017
Dec. 31, 2016
Revenues from External Customers and Long-Lived Assets [Line Items]      
Revenues [1] $ 53,647 $ 52,546 $ 52,824
Developed Europe [Member]      
Revenues from External Customers and Long-Lived Assets [Line Items]      
Revenues [2] 9,116 8,508 9,306
Euro Member Countries, Euro | Developed Europe [Member]      
Revenues from External Customers and Long-Lived Assets [Line Items]      
Revenues $ 7,300 $ 6,800 $ 7,200
[1] Amounts may not add due to rounding.
[2] Developed Europe region includes the following markets: Western Europe, Scandinavian countries and Finland. Revenues denominated in euros were $7.3 billion in 2018, $6.8 billion in 2017 and $7.2 billion in 2016.