Investments In Affiliates Accounted For Using The Equity Method (Liberty Broadband's Consolidated Statement Of Operations) (Details) - Liberty Broadband - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Revenue	$ 3	$ 21	$ 10	$ 27
Operating expenses, net	9	14	29	41
Operating income (loss)	(6)	7	(19)	(14)
Share of earnings (losses) of affiliates	(5)	19	25	570
Realized and unrealized gains (losses) on financial instruments, net	3		5	93
Gain (loss) on dilution of investment in affiliate	(4)	(16)	(42)	760
Other income (expense), net	(5)	(4)	(14)	(5)
Income tax benefit (expense)	7	(2)	18	(532)
Net earnings (loss)	$ (10)	$ 4	$ (27)	$ 872