Reportable Segments (Schedule of Reconciliation of Adjusted OIBDA to Net Income) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Segment Reporting [Abstract]
Net income available to Discovery, Inc.	$ 300	$ 262	$ 948	$ 1,593
Net income attributable to redeemable noncontrolling interests	1	6	7	15
Net income attributable to noncontrolling interests	29	29	82	94
Income tax (benefit) expense	(11)	147	275	29
Income before income taxes	319	444	1,312	1,731
Other expense, net	28	1	92	10
Loss from equity investees, net	18	11	62	20
Loss on extinguishment of debt	5	0	76	28
Interest expense, net	161	163	485	515
Operating income	531	619	2,027	2,304
Restructuring and other charges	53	8	75	20
Impairment of goodwill and other intangible assets	0	155	38	155
Depreciation and amortization	341	322	1,001	1,014
Employee share-based compensation	29	11	53	80
Transaction and integration costs	0	11	0	22
Settlement of a withholding tax claim	0	0	0	(29)
Total Adjusted OIBDA	$ 954	$ 1,126	$ 3,194	$ 3,566