SCHEDULE II. VALUATION AND QUALIFYING ACCOUNTS (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Movement in valuation and qualifying accounts
Balance at Beginning of Period	$ 5	$ 4	$ 5
Additions, Charged to Costs and Expenses	1	3	1
Additions, Charged to Other Accounts	0	0	0
Deductions	(2)	(2)	(2)
Balance at End of Period	4	5	4
Valuation Allowance on deferred tax assets
Movement in valuation and qualifying accounts
Balance at Beginning of Period	43	47	45
Additions, Charged to Costs and Expenses	0	0	0
Additions, Charged to Other Accounts	0	0	2
Deductions	(5)	(4)	0
Balance at End of Period	$ 38	43	$ 47
Valuation Allowance on deferred tax assets | Other Comprehensive Income (Loss)
Movement in valuation and qualifying accounts
Deductions		(1)
Income Tax Benefit [Member] | Valuation Allowance on deferred tax assets
Movement in valuation and qualifying accounts
Deductions		$ (3)