Restructuring, and Other Corporate Matters (Rollforward) (Details) - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Restructuring Reserve [Roll Forward]
Restructuring reserve, beginning balance	$ 396	$ 284
Charges	542	418	$ 309
Payments	(398)	(230)
Other	(38)	(9)
Restructuring reserve, ending balance	372	396	284
Restructuring Charges Excluding Stock-Based Compensation and Lease Impairments [Member]
Restructuring Reserve [Roll Forward]
Charges	412	351
Stock-Based Compensation Expense [Member]
Restructuring Reserve [Roll Forward]
Charges	88	67
Lease Impairments [Member]
Restructuring Reserve [Roll Forward]
Charges	42
Operating Segments [Member] \| TV Entertainment [Member]
Restructuring Reserve [Roll Forward]
Restructuring reserve, beginning balance	99	54
Payments	(111)	(82)
Other	(13)	(1)
Restructuring reserve, ending balance	112	99	54
Operating Segments [Member] \| TV Entertainment [Member] \| Restructuring Charges Excluding Stock-Based Compensation and Lease Impairments [Member]
Restructuring Reserve [Roll Forward]
Charges	137	128
Operating Segments [Member] \| Cable Networks [Member]
Restructuring Reserve [Roll Forward]
Restructuring reserve, beginning balance	137	151
Payments	(158)	(104)
Other	(14)	(7)
Restructuring reserve, ending balance	144	137	151
Operating Segments [Member] \| Cable Networks [Member] \| Restructuring Charges Excluding Stock-Based Compensation and Lease Impairments [Member]
Restructuring Reserve [Roll Forward]
Charges	179	97
Operating Segments [Member] \| Filmed Entertainment [Member]
Restructuring Reserve [Roll Forward]
Restructuring reserve, beginning balance	17	22
Payments	(12)	(12)
Other	0	(1)
Restructuring reserve, ending balance	30	17	22
Operating Segments [Member] \| Filmed Entertainment [Member] \| Restructuring Charges Excluding Stock-Based Compensation and Lease Impairments [Member]
Restructuring Reserve [Roll Forward]
Charges	25	8
Corporate [Member]
Restructuring Reserve [Roll Forward]
Restructuring reserve, beginning balance	143	57
Payments	(117)	(32)
Other	(11)	0
Restructuring reserve, ending balance	86	143	$ 57
Corporate [Member] \| Restructuring Charges Excluding Stock-Based Compensation and Lease Impairments [Member]
Restructuring Reserve [Roll Forward]
Charges	$ 71	$ 118

Amount of cash payments made as the result of exit or disposal activities. Excludes payments associated with a discontinued operation or an asset retirement obligation.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 420
-SubTopic 10
-Section 50
-Paragraph 1
-Subparagraph (b)(2)
-URI http://asc.fasb.org/extlink&oid=6394359&loc=d3e17939-110869

Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 17
-Subparagraph (f)
-URI http://asc.fasb.org/extlink&oid=121586364&loc=d3e3367-108585

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Amount of expenses associated with exit or disposal activities pursuant to an authorized plan. Excludes expenses related to a discontinued operation or an asset retirement obligation.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 420
-SubTopic 10
-Section S99
-Paragraph 1
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Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 420
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-Section S99
-Paragraph 2
-Subparagraph (SAB Topic 5.P.4(b))
-URI http://asc.fasb.org/extlink&oid=115931487&loc=d3e140904-122747

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Carrying amount (including both current and noncurrent portions of the accrual) as of the balance sheet date pertaining to a specified type of cost associated with exit from or disposal of business activities or restructuring pursuant to a duly authorized plan.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 420
-SubTopic 10
-Section 50
-Paragraph 1
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-URI http://asc.fasb.org/extlink&oid=6394359&loc=d3e17939-110869

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A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.

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Restructuring Reserve, Other Adjustment

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