Schedule I - Additional Information (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Condensed Financial Statements, Captions [Line Items]
Other Comprehensive Income (Loss), Net of Tax	$ (34)	$ 6	$ (2)
Amount of Restricted Net Assets for Consolidated and Unconsolidated Subsidiaries	3,200	3,200
AOCI Attributable to Parent [Member] | Parent Company [Member]
Condensed Financial Statements, Captions [Line Items]
Other Comprehensive Income (Loss), Net of Tax	$ (30)	$ 6	$ (2)