Commitments and Contingencies (Streaming Content) (Narrative) (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Contractual Obligation [Line Items]
Total streaming content obligations	$ 17,694,642	$ 14,479,487
Current content liabilities	4,173,041	3,632,711
Non-current content liabilities	3,329,796	2,894,654
Unrecorded streaming obligations	10,200,000	8,000,000
Current Content Liabilities [Member]
Contractual Obligation [Line Items]
Current content liabilities	4,200,000	3,600,000
Non-current Content Liabilities [Member]
Contractual Obligation [Line Items]
Non-current content liabilities	$ 3,300,000	$ 2,900,000