Employee Benefit Plans - Narrative (Details) $ in Millions	12 Months Ended
	Dec. 31, 2019 USD ($) investment_pool	Dec. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)
Defined Benefit Plan Disclosure [Line Items]
Contributions to defined contribution plans	$ 65	$ 44	$ 44
U.S. and other plans
Defined Benefit Plan Disclosure [Line Items]
Plan assets investments	$ 167	0
U.S. and other plans | On-risk assets
Defined Benefit Plan Disclosure [Line Items]
Plan assets target allocation percentage	50.00%
U.S. and other plans | Off-risk assets
Defined Benefit Plan Disclosure [Line Items]
Plan assets target allocation percentage	50.00%
U.K. plan
Defined Benefit Plan Disclosure [Line Items]
Number of plan asset investment pools | investment_pool	2
Plan assets investments	$ 860	$ 0
U.K. plan | On-risk assets
Defined Benefit Plan Disclosure [Line Items]
Plan assets target allocation percentage	45.00%
U.K. plan | Off-risk assets
Defined Benefit Plan Disclosure [Line Items]
Plan assets target allocation percentage	55.00%
Fair Value Measured at Net Asset Value Per Share | Hedge funds
Defined Benefit Plan Disclosure [Line Items]
Plan assets investments	$ 48