Consolidated Statements of Equity (unaudited) - USD ($) shares in Millions, $ in Millions	Total	Cumulative effect of accounting change	Preferred Stock	Common Stock	Additional Paid-In Capital	Treasury Stock	Retained Earnings	Retained Earnings Cumulative effect of accounting change	Accumulated Other Comprehensive Loss	Accumulated Other Comprehensive Loss Cumulative effect of accounting change	Discovery, Inc. Stockholders’ Equity	Discovery, Inc. Stockholders’ Equity Cumulative effect of accounting change	Noncontrolling Interests
Beginning balance (in shares) at Dec. 31, 2018			14	691
Beginning balance at Dec. 31, 2018	$ 10,102	$ 0	$ 0	$ 7	$ 10,647	$ (6,737)	$ 5,254	$ 30	$ (785)	$ (30)	$ 8,386	$ 0	$ 1,716
Increase (Decrease) in Stockholders' Equity
Net income available to Discovery, Inc. and attributable to noncontrolling interests	413						384				384		29
Other comprehensive loss	(80)								(80)		(80)
Share-based compensation	38				38						38
Tax settlements associated with share-based plans	(21)				(21)						(21)
Dividends paid to noncontrolling interests	(153)												(153)
Issuance of stock in connection with share-based plans (in shares)				2
Issuance of stock in connection with share-based plans	6				6						6
Redeemable noncontrolling interest adjustments to redemption value	(5)						(5)				(5)
Ending balance (in shares) at Mar. 31, 2019			14	693
Ending balance at Mar. 31, 2019	10,300	5	$ 0	$ 7	10,670	(6,737)	5,663	5	(895)	0	8,708	5	1,592
Beginning balance (in shares) at Dec. 31, 2018			14	691
Beginning balance at Dec. 31, 2018	10,102	0	$ 0	$ 7	10,647	(6,737)	5,254	30	(785)	(30)	8,386	0	1,716
Increase (Decrease) in Stockholders' Equity
Other comprehensive loss	(214)
Settlement of common stock repurchase contract	0
Ending balance (in shares) at Sep. 30, 2019			13	705
Ending balance at Sep. 30, 2019	11,133		$ 0	$ 7	10,718	(7,037)	6,859		(1,029)		9,518		1,615
Beginning balance (in shares) at Mar. 31, 2019			14	693
Beginning balance at Mar. 31, 2019	10,300	5	$ 0	$ 7	10,670	(6,737)	5,663	5	(895)	0	8,708	5	1,592
Increase (Decrease) in Stockholders' Equity
Net income available to Discovery, Inc. and attributable to noncontrolling interests	983						947				947		36
Other comprehensive loss	(18)								(18)		(18)
Preferred stock conversion (in shares)			(1)	12
Preferred stock conversion	0
Prepayments for common stock repurchase contracts, net of settlements	(45)				(45)						(45)
Share-based compensation	19				19						19
Dividends paid to noncontrolling interests	(28)												(28)
Issuance of stock in connection with share-based plans (in shares)				0
Issuance of stock in connection with share-based plans	4				4						4
Redeemable noncontrolling interest adjustments to redemption value	1						1				1
Ending balance (in shares) at Jun. 30, 2019			13	705
Ending balance at Jun. 30, 2019	11,221		$ 0	$ 7	10,648	(6,737)	6,616		(913)		9,621		1,600
Increase (Decrease) in Stockholders' Equity
Net income available to Discovery, Inc. and attributable to noncontrolling interests	291						262				262		29
Other comprehensive loss	(116)								(116)		(116)
Share-based compensation	18				18						18
Repurchases of stock (in shares)			0
Repurchases of stock	(300)					(300)					(300)
Tax settlements associated with share-based plans	(1)				(1)						(1)
Dividends paid to noncontrolling interests	(14)												(14)
Issuance of stock in connection with share-based plans (in shares)				0
Issuance of stock in connection with share-based plans	3				3						3
Settlement of common stock repurchase contract	50				50						50
Redeemable noncontrolling interest adjustments to redemption value	(19)						(19)				(19)
Ending balance (in shares) at Sep. 30, 2019			13	705
Ending balance at Sep. 30, 2019	11,133		$ 0	$ 7	10,718	(7,037)	6,859		(1,029)		9,518		1,615
Beginning balance (in shares) at Dec. 31, 2019			13	715
Beginning balance at Dec. 31, 2019	11,524	2	$ 0	$ 7	10,747	(7,374)	7,333	2	(822)	0	9,891	2	1,633
Increase (Decrease) in Stockholders' Equity
Net income available to Discovery, Inc. and attributable to noncontrolling interests	405						377				377		28
Other comprehensive loss	(300)								(300)		(300)
Share-based compensation	21				21						21
Repurchases of stock (in shares)			0
Repurchases of stock	(523)					(523)					(523)
Tax settlements associated with share-based plans	(30)				(30)						(30)
Dividends paid to noncontrolling interests	(170)												(170)
Issuance of stock in connection with share-based plans (in shares)				1
Issuance of stock in connection with share-based plans	32				32						32
Other adjustments to stockholders' equity	1												1
Ending balance (in shares) at Mar. 31, 2020			13	716
Ending balance at Mar. 31, 2020	10,962	(3)	$ 0	$ 7	10,770	(7,897)	7,712	(3)	(1,122)		9,470	(3)	1,492
Beginning balance (in shares) at Dec. 31, 2019			13	715
Beginning balance at Dec. 31, 2019	11,524	2	$ 0	$ 7	10,747	(7,374)	7,333	2	(822)	$ 0	9,891	2	1,633
Increase (Decrease) in Stockholders' Equity
Other comprehensive loss	(76)
Settlement of common stock repurchase contract	14
Ending balance (in shares) at Sep. 30, 2020			13	716
Ending balance at Sep. 30, 2020	11,597		$ 0	$ 7	10,825	(8,125)	8,278		(898)		10,087		1,510
Beginning balance (in shares) at Mar. 31, 2020			13	716
Beginning balance at Mar. 31, 2020	10,962	$ (3)	$ 0	$ 7	10,770	(7,897)	7,712	$ (3)	(1,122)		9,470	$ (3)	1,492
Increase (Decrease) in Stockholders' Equity
Net income available to Discovery, Inc. and attributable to noncontrolling interests	296						271				271		25
Other comprehensive loss	101								101		101
Share-based compensation	25				25						25
Tax settlements associated with share-based plans	(1)				(1)						(1)
Dividends paid to noncontrolling interests	(27)												(27)
Issuance of stock in connection with share-based plans (in shares)				0
Issuance of stock in connection with share-based plans	2				2						2
Other adjustments to stockholders' equity	3				2						2		1
Ending balance (in shares) at Jun. 30, 2020			13	716
Ending balance at Jun. 30, 2020	11,358		$ 0	$ 7	10,798	(7,897)	7,980		(1,021)		9,867		1,491
Increase (Decrease) in Stockholders' Equity
Net income available to Discovery, Inc. and attributable to noncontrolling interests	329						300				300		29
Other comprehensive loss	123								123		123
Share-based compensation	26				26						26
Repurchases of stock (in shares)			0
Repurchases of stock	(228)					(228)					(228)
Dividends paid to noncontrolling interests	(10)												(10)
Issuance of stock in connection with share-based plans (in shares)				0
Issuance of stock in connection with share-based plans	1				1						1
Redeemable noncontrolling interest adjustments to redemption value	(2)						(2)				(2)
Ending balance (in shares) at Sep. 30, 2020			13	716
Ending balance at Sep. 30, 2020	$ 11,597		$ 0	$ 7	$ 10,825	$ (8,125)	$ 8,278		$ (898)		$ 10,087		$ 1,510