Schedule II - Valuation and Qualifying Accounts (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Allowance for doubtful accounts and estimated returns
Movement in Valuation Allowances and Reserves [Roll Forward]
Beginning balance of valuation allowance and reserves	$ 59	$ 54	$ 67
Charged to costs and expenses, additions	18	7	0
Other, additions	0	0	0
Deductions	4	2	13
Ending balance of valuation allowance and reserves	73	59	54
Valuation allowance for deferred tax assets
Movement in Valuation Allowances and Reserves [Roll Forward]
Beginning balance of valuation allowance and reserves	0	0	6
Charged to costs and expenses, additions	0	0	0
Other, additions	0	0	0
Deductions	0	0	6
Ending balance of valuation allowance and reserves	$ 0	$ 0	$ 0