Share-Based Compensation - Narrative (Details) - USD ($) shares in Millions, $ in Millions	1 Months Ended	3 Months Ended		6 Months Ended
	Feb. 28, 2021	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Class of Stock [Line Items]
Non-cash expense recognized		$ 37	$ 32	$ 73	$ 73
Acquisition costs		10	$ 2	$ 28	14
Time Based Restricted Units
Class of Stock [Line Items]
Cost not yet recognized, period for recognition (in years)				3 years
Performance Based Restricted Stock Units
Class of Stock [Line Items]
Cost not yet recognized, period for recognition (in years)	3 years
Unrecognized compensation expense	$ 38	29		$ 29
Vested stock options (in shares)	0.4
Stock-based compensation		6		9
Amount of non-cash compensation remaining in fiscal period		$ 12		$ 12
Maximum | Performance Based Restricted Stock Units
Class of Stock [Line Items]
Unrecognized compensation expense	$ 77
Shares reserved for future issuance (in shares)	0.7
Bridge2 Solutions
Class of Stock [Line Items]
Acquisition costs					10
Bridge2 Solutions | Bakkt
Class of Stock [Line Items]
Capital call amount					$ 300