Schedule II - Valuation and Qualifying Accounts (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Allowance for doubtful accounts and estimated returns
Movement in Valuation Allowances and Reserves [Roll Forward]
Valuation Allowances and Reserves, Beginning Balance	$ 54	$ 67	$ 61
Valuation Allowances and Reserves, Charged to Cost and Expense	7	0	15
Valuation Allowances and Reserves, Charged to Other Accounts	0	0	0
Valuation Allowances and Reserves, Deductions	2	13	9
Valuation Allowances and Reserves, Ending Balance	59	54	67
Valuation allowance for deferred tax assets
Movement in Valuation Allowances and Reserves [Roll Forward]
Valuation Allowances and Reserves, Beginning Balance	0	6	1
Valuation Allowances and Reserves, Charged to Cost and Expense	0	0	6
Valuation Allowances and Reserves, Charged to Other Accounts	0	0	0
Valuation Allowances and Reserves, Deductions	0	6	1
Valuation Allowances and Reserves, Ending Balance	$ 0	$ 0	$ 6