Revenue Recognition - Disaggregation of Revenue by Geographical Area (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Disaggregation of Revenue [Line Items]
Revenue	$ 17,279	$ 15,381	$ 14,619
United States
Disaggregation of Revenue [Line Items]
Revenue	10,232	9,163	8,758
North America (excluding United States)
Disaggregation of Revenue [Line Items]
Revenue	341	298	322
France
Disaggregation of Revenue [Line Items]
Revenue	2,165	2,006	1,903
United Kingdom
Disaggregation of Revenue [Line Items]
Revenue	2,070	1,799	1,701
Europe (excluding France and United Kingdom)
Disaggregation of Revenue [Line Items]
Revenue	2,359	1,930	1,644
Other
Disaggregation of Revenue [Line Items]
Revenue	112	$ 185	$ 291
Eliminations
Disaggregation of Revenue [Line Items]
Revenue	(129)
Eliminations | United States
Disaggregation of Revenue [Line Items]
Revenue	(19)
Eliminations | North America (excluding United States)
Disaggregation of Revenue [Line Items]
Revenue	0
Eliminations | France
Disaggregation of Revenue [Line Items]
Revenue	(18)
Eliminations | United Kingdom
Disaggregation of Revenue [Line Items]
Revenue	(70)
Eliminations | Europe (excluding France and United Kingdom)
Disaggregation of Revenue [Line Items]
Revenue	(18)
Eliminations | Other
Disaggregation of Revenue [Line Items]
Revenue	(4)
Transportation
Disaggregation of Revenue [Line Items]
Revenue	11,343
Transportation | United States
Disaggregation of Revenue [Line Items]
Revenue	8,055
Transportation | North America (excluding United States)
Disaggregation of Revenue [Line Items]
Revenue	274
Transportation | France
Disaggregation of Revenue [Line Items]
Revenue	1,496
Transportation | United Kingdom
Disaggregation of Revenue [Line Items]
Revenue	704
Transportation | Europe (excluding France and United Kingdom)
Disaggregation of Revenue [Line Items]
Revenue	793
Transportation | Other
Disaggregation of Revenue [Line Items]
Revenue	21
Transportation | Eliminations
Disaggregation of Revenue [Line Items]
Revenue	(145)
Logistics
Disaggregation of Revenue [Line Items]
Revenue	6,065
Logistics | United States
Disaggregation of Revenue [Line Items]
Revenue	2,196
Logistics | North America (excluding United States)
Disaggregation of Revenue [Line Items]
Revenue	67
Logistics | France
Disaggregation of Revenue [Line Items]
Revenue	687
Logistics | United Kingdom
Disaggregation of Revenue [Line Items]
Revenue	1,436
Logistics | Europe (excluding France and United Kingdom)
Disaggregation of Revenue [Line Items]
Revenue	1,584
Logistics | Other
Disaggregation of Revenue [Line Items]
Revenue	$ 95