Redeemable Noncontrolling Interests (Narrative) (Details)	Dec. 31, 2018	Dec. 31, 2014
Levity [Member]
Noncontrolling Interest [Line Items]
Noncontrolling interest, right to put (as a percentage)	50.00%
New Video (BBC AMERICA) [Member]
Noncontrolling Interest [Line Items]
Controlling interest (as a percentage)		49.90%
New Video (BBC AMERICA) [Member] | Unnamed Subsidiary [Member]
Noncontrolling Interest [Line Items]
Noncontrolling Interest, Ownership Percentage by Noncontrolling Owners		50.10%