Earnings (Loss) Per Common Share (Earrings Per Share Basic and Diluted) (Details) - shares shares in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Earnings Per Share, Diluted, by Common Class, Including Two Class Method [Line Items]
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount	28	16	28	16
Basic EPS (WA shares outstanding)	459	448	467	451
Potentially dilutive shares	2	4	4	3
Diluted EPS (WA shares outstanding)	461	452	471	454
Liberty Ventures common stock
Earnings Per Share, Diluted, by Common Class, Including Two Class Method [Line Items]
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount	0	0	2	0
Basic EPS (WA shares outstanding)		86	86	85
Potentially dilutive shares		1	1	1
Diluted EPS (WA shares outstanding)		87	87	86