Employee Benefit Plans - Funded Status of Defined Benefit Pension Plans (Details) $ in Millions	12 Months Ended
	Dec. 31, 2019 USD ($)
Change in projected benefit obligations:
Interest cost	$ (9)
U.K. plan
Change in projected benefit obligations:
Plan benefit obligations, beginning balance	0
Acquired	(687)
Interest cost	(6)
Actuarial gain (loss)	28
Benefits paid	12
Foreign currency translation	(19)
Plan benefit obligations, ending balance	(672)
Change in fair value of plan assets:
Fair value of plan assets, beginning balance	0
Acquired	866
Actual return on plan assets	(19)
Benefits paid	(12)
Foreign currency translation	25
Fair value of plan assets, ending balance	860
Funded status of the plans	188
U.S. and other plans
Change in projected benefit obligations:
Plan benefit obligations, beginning balance	0
Acquired	(219)
Interest cost	(3)
Actuarial gain (loss)	(15)
Benefits paid	12
Foreign currency translation	0
Plan benefit obligations, ending balance	(225)
Change in fair value of plan assets:
Fair value of plan assets, beginning balance	0
Acquired	160
Actual return on plan assets	19
Benefits paid	(12)
Foreign currency translation	0
Fair value of plan assets, ending balance	167
Funded status of the plans	$ (58)