Employee Benefit Plans - Funded Status of Plan (Details) - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018
United States
Defined Benefit Plan Disclosure [Line Items]
Funded status at end of year	$ 1	$ (77)
Amount recognized in balance sheet:
Long-term assets	76	0
Current liabilities	(6)	(5)
Long-term liabilities	(69)	(72)
Net amount recognized	1	(77)
Plans with projected and accumulated benefit obligation in excess of plan assets:
Projected and accumulated benefit obligation	75	1,659
Fair value of plan assets	0	1,582
U.K. Plan
Defined Benefit Plan Disclosure [Line Items]
Funded status at end of year	39	63
Amount recognized in balance sheet:
Long-term assets	39	63
Current liabilities	0	0
Long-term liabilities	0	0
Net amount recognized	39	63
Plans with projected and accumulated benefit obligation in excess of plan assets:
Projected and accumulated benefit obligation	0	0
Fair value of plan assets	0	$ 0
Qualified Plan | United States
Defined Benefit Plan Disclosure [Line Items]
Funded status at end of year	$ 76