SCHEDULE II. VALUATION AND QUALIFYING ACCOUNTS (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Movement in valuation and qualifying accounts
Balance at Beginning of Period	$ 13	$ 11	$ 11
Additions, Charged to Costs and Expenses	6	5	4
Additions, Charged to Other Accounts	0	0	0
Deductions	(5)	(3)	(4)
Balance at End of Period	14	13	11
Other Comprehensive Income (Loss)
Movement in valuation and qualifying accounts
Deductions	(1)
Valuation Allowance on deferred tax assets
Movement in valuation and qualifying accounts
Balance at Beginning of Period	47	45	49
Additions, Charged to Costs and Expenses	0	0	11
Additions, Charged to Other Accounts	0	2	0
Deductions	(4)	0	(15)
Balance at End of Period	43	47	45
Valuation Allowance on deferred tax assets | Other Comprehensive Income (Loss)
Movement in valuation and qualifying accounts
Additions, Charged to Other Accounts		$ 2
Deductions	$ (3)		(2)
Certain net operating loss carryforward
Movement in valuation and qualifying accounts
Deductions			$ (13)