Earnings Per Share (Calculated Earnings (Loss) Per Share) (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Numerator:
Net income	$ 330	$ 297	$ 1,037	$ 1,702
Less:
Net income attributable to noncontrolling interests	(29)	(29)	(82)	(94)
Net income attributable to redeemable noncontrolling interests	(1)	(6)	(7)	(15)
Redeemable noncontrolling interest adjustments to redemption value	(4)	(12)	(3)	(16)
Net income allocated to Discovery, Inc. Series A, B and C common and Series C-1 convertible preferred stockholders for basic net income per share	265	225	846	1,420
Allocation of net income to:
Total	265	225	846	1,420
Series A-1 Convertible Preferred Stock
Less:
Allocation of undistributed income to Series A-1 convertible preferred stock	(31)	(25)	(99)	(157)
Add:
Allocation of undistributed income to Series A-1 convertible preferred stockholders	31	25	99	157
Series A, B and C Common Stock and C1 Preferred Stock
Less:
Net income allocated to Discovery, Inc. Series A, B and C common and Series C-1 convertible preferred stockholders for basic net income per share	265	225	846	1,420
Allocation of net income to:
Total	265	225	846	1,420
Series A, B and C Common Stock
Less:
Net income allocated to Discovery, Inc. Series A, B and C common and Series C-1 convertible preferred stockholders for basic net income per share	223	188	714	1,173
Allocation of net income to:
Total	223	188	714	1,173
Add:
Net income allocated to Discovery, Inc. Series A, B and C common stockholders for diluted net income per share	$ 296	$ 250	$ 945	$ 1,577
Denominator — weighted average:
Series A, B and C common shares outstanding — basic (in shares)	505	535	510	529
Impact of assumed preferred stock conversion (in shares)	165	175	165	182
Dilutive effect of share-based awards (in shares)	2	3	2	3
Series A, B and C common shares outstanding — diluted (in shares)	672	713	677	714
Basic net income per share allocated to:
Basic net income (loss) per share (in dollars per share)	$ 0.44	$ 0.35	$ 1.40	$ 2.22
Diluted net income per share allocated to:
Diluted net income (loss) per share (in dollars per share)	$ 0.44	$ 0.35	$ 1.40	$ 2.21
Series C-1 Convertible Preferred Stock
Less:
Net income allocated to Discovery, Inc. Series A, B and C common and Series C-1 convertible preferred stockholders for basic net income per share	$ 42	$ 37	$ 132	$ 247
Allocation of net income to:
Total	$ 42	$ 37	$ 132	$ 247
Denominator — weighted average:
Series C-1 convertible preferred stock outstanding — basic and diluted (in shares)	5	5	5	6
Basic net income per share allocated to:
Basic net income (loss) per share (in dollars per share)	$ 8.55	$ 6.82	$ 27.11	$ 42.94
Diluted net income per share allocated to:
Diluted net income (loss) per share (in dollars per share)	$ 8.53	$ 6.80	$ 27.03	$ 42.77