Stockholders' Equity - Accumulated Other Comprehensive Loss Primarily Comprised of Accumulated Foreign Currency Translation (Details) - USD ($) $ in Millions		Dec. 31, 2020	Dec. 31, 2019
Accumulated Other Comprehensive Income Loss [Line Items]
Accumulated other comprehensive income (loss)		$ (34)	$ (63)
Cumulative Foreign Currency Translation Adjustments, Net of Tax
Accumulated Other Comprehensive Income Loss [Line Items]
Accumulated other comprehensive income (loss)	[1]	$ (34)	$ (63)

[1] Deferred income tax liabilities related to these amounts are not material.