Revenue Recognition - Disaggregation of Revenue by Geographical Area (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Disaggregation of Revenue [Line Items]
Revenue	$ 3,502	$ 4,238	$ 7,366	$ 8,358
United States
Disaggregation of Revenue [Line Items]
Revenue	2,004	2,487	4,233	4,875
North America (excluding United States)
Disaggregation of Revenue [Line Items]
Revenue	81	88	166	173
France
Disaggregation of Revenue [Line Items]
Revenue	394	517	852	1,045
United Kingdom
Disaggregation of Revenue [Line Items]
Revenue	452	518	947	1,023
Europe (excluding France and United Kingdom)
Disaggregation of Revenue [Line Items]
Revenue	525	600	1,096	1,189
Other
Disaggregation of Revenue [Line Items]
Revenue	46	28	72	53
Eliminations/Other
Disaggregation of Revenue [Line Items]
Revenue	(29)	(35)	(61)	(68)
Eliminations/Other | United States
Disaggregation of Revenue [Line Items]
Revenue	(10)	(7)	(19)	(12)
Eliminations/Other | North America (excluding United States)
Disaggregation of Revenue [Line Items]
Revenue	0	0	0	0
Eliminations/Other | France
Disaggregation of Revenue [Line Items]
Revenue	(3)	(6)	(6)	(11)
Eliminations/Other | United Kingdom
Disaggregation of Revenue [Line Items]
Revenue	(11)	(18)	(27)	(36)
Eliminations/Other | Europe (excluding France and United Kingdom)
Disaggregation of Revenue [Line Items]
Revenue	(4)	(4)	(7)	(8)
Eliminations/Other | Other
Disaggregation of Revenue [Line Items]
Revenue	(1)	0	(2)	(1)
Transportation
Disaggregation of Revenue [Line Items]
Revenue	2,127	2,747	4,586	5,406
Transportation | United States
Disaggregation of Revenue [Line Items]
Revenue	1,505	1,924	3,207	3,760
Transportation | North America (excluding United States)
Disaggregation of Revenue [Line Items]
Revenue	71	73	142	140
Transportation | France
Disaggregation of Revenue [Line Items]
Revenue	255	351	566	715
Transportation | United Kingdom
Disaggregation of Revenue [Line Items]
Revenue	125	186	307	374
Transportation | Europe (excluding France and United Kingdom)
Disaggregation of Revenue [Line Items]
Revenue	146	207	334	408
Transportation | Other
Disaggregation of Revenue [Line Items]
Revenue	25	6	30	9
Transportation | Eliminations/Other
Disaggregation of Revenue [Line Items]
Revenue	(38)	(40)	(82)	(77)
Logistics
Disaggregation of Revenue [Line Items]
Revenue	1,404	1,526	2,841	3,020
Logistics | United States
Disaggregation of Revenue [Line Items]
Revenue	509	570	1,045	1,127
Logistics | North America (excluding United States)
Disaggregation of Revenue [Line Items]
Revenue	10	15	24	33
Logistics | France
Disaggregation of Revenue [Line Items]
Revenue	142	172	292	341
Logistics | United Kingdom
Disaggregation of Revenue [Line Items]
Revenue	338	350	667	685
Logistics | Europe (excluding France and United Kingdom)
Disaggregation of Revenue [Line Items]
Revenue	383	397	769	789
Logistics | Other
Disaggregation of Revenue [Line Items]
Revenue	$ 22	$ 22	$ 44	$ 45