Stockholders' Equity - Narrative (Details) shares in Millions, $ in Millions	3 Months Ended		12 Months Ended
	Mar. 31, 2020 USD ($) shares	Mar. 31, 2019 USD ($) shares	Dec. 31, 2019
Class of Stock [Line Items]
Compensation expense | $	$ 4	$ 4
RSUs
Class of Stock [Line Items]
Shares granted (in shares)	1.1	1.9
Number of installment anniversaries			3
PSUs
Class of Stock [Line Items]
Shares granted (in shares)	0.5
Vesting period	3 years
PSUs | Base Grant Multiplied By Achieved TSR In Initial Year (up to)
Class of Stock [Line Items]
Vesting percentage	33.333%
PSUs | Base Grant Multiplied BY Achieved TSR in Final Year Less Initial Year Vesting (up to)
Class of Stock [Line Items]
Vesting percentage	100.00%
Minimum | PSUs
Class of Stock [Line Items]
Shares of common stock, target based award, percentage	0.00%
Maximum | PSUs
Class of Stock [Line Items]
Shares of common stock, target based award, percentage	200.00%