SCHEDULE II. VALUATION AND QUALIFYING ACCOUNTS (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Allowances for doubtful accounts, deducted from accounts receivable
Movement in valuation and qualifying accounts
Balance at Beginning of Period	$ 14	$ 22	$ 26
Additions, Charged to Costs and Expenses	4	3	5
Deductions	(7)	(11)	(9)
Balance at End of Period	11	14	22
Valuation Allowance on deferred tax assets
Movement in valuation and qualifying accounts
Balance at Beginning of Period	66	662	785
Additions, Charged to Costs and Expenses	36	(539)	(36)
Additions, Charged to Other Accounts	(53)	(57)	(87)
Balance at End of Period	$ 49	66	$ 662
Valuation Allowance on deferred tax assets | Other comprehensive income
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		$ (55)