Commitments and Contingencies - Streaming Content - Narrative (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Contractual Obligation [Line Items]
Streaming obligations included in current content liabilities	$ 18,645,758	$ 17,694,642
Streaming obligations not reflected on Consolidated Balance Sheets	10,400,000	10,200,000
Current content liabilities
Contractual Obligation [Line Items]
Streaming obligations included in non-current content liabilities	4,600,000	4,200,000
Non-current content liabilities
Contractual Obligation [Line Items]
Streaming obligations included in non-current content liabilities	$ 3,600,000	$ 3,300,000