Schedule II - Valuation and Qualifying Accounts (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Allowance for doubtful accounts and estimated returns
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
Beginning balance of valuation allowance and reserves	$ 82	$ 77	$ 73
Charged to Costs and Expenses, additions	6	15	8
Other, additions	0	0	0
Deductions	12	10	4
Ending balance of valuation allowance and reserves	76	82	77
Valuation allowance for deferred tax assets
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
Beginning balance of valuation allowance and reserves	54	9	0
Charged to Costs and Expenses, additions	12	45	9
Other, additions	0	0	0
Deductions	7	0	0
Ending balance of valuation allowance and reserves	$ 59	$ 54	$ 9