Segment Reporting - Net Revenues by Geographic Area (Details) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Segment Reporting Information [Line Items]
Net revenues	$ 6,913	$ 6,355	$ 6,062	$ 6,538	$ 6,773	$ 6,288	$ 6,112	$ 6,765	$ 25,868	$ 25,938	$ 25,896
United States
Segment Reporting Information [Line Items]
Net revenues									6,625	6,401	6,275
Other
Segment Reporting Information [Line Items]
Net revenues									$ 19,243	$ 19,537	$ 19,621