SCHEDULE II. VALUATION AND QUALIFYING ACCOUNTS (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Allowances for doubtful accounts, deducted from accounts receivable
Movement in valuation and qualifying accounts
Balance at Beginning of Period	$ 11	$ 14	$ 22
Additions, Charged to Costs and Expenses	4	4	3
Deductions	(4)	(7)	(11)
Balance at End of Period	11	11	14
Valuation Allowance on deferred tax assets
Movement in valuation and qualifying accounts
Balance at Beginning of Period	49	66	662
Additions, Charged to Costs and Expenses	11	36	(539)
Additions, Charged to Other Accounts	(15)	(53)	(57)
Balance at End of Period	45	$ 49	66
Valuation Allowance on deferred tax assets | Other Comprehensive Income (Loss)
Movement in valuation and qualifying accounts
Additions, Charged to Other Accounts			(2)
Certain net operating loss carryforward
Movement in valuation and qualifying accounts
Additions, Charged to Other Accounts	$ (13)		$ (55)