Summary of Significant Accounting Policies - Schedule of Reconciliation of Allowance for Doubtful Accounts (Details) - USD ($) $ in Millions	9 Months Ended	12 Months Ended
	Sep. 30, 2020	Dec. 31, 2019
Accounts, Notes, Loans and Financing Receivable [Line Items]
Accounting Standards Update [Extensible List]		us-gaap:AccountingStandardsUpdate201613Member
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Allowance for doubtful accounts, beginning balance	$ 8
Bad debt expense	11
Charge-offs	(7)
Allowance for doubtful accounts, ending balance	25	$ 8
Cumulative Effect, Period Of Adoption, Adjustment
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Allowance for doubtful accounts, beginning balance	$ 13
Allowance for doubtful accounts, ending balance		$ 13