CONDENSED CONSOLIDATED FINANCIAL STATEMENTS - Balance Sheets (Details) - USD ($) $ in Millions		Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Condensed Financial Statements, Captions [Line Items]
Cash and cash equivalents		$ 1,259.0	$ 1,333.0
Accounts receivable		1,060.0	1,132.0
Other current assets		898.0	448.0
Total current assets		3,217.0	2,913.0
Property and equipment, net		823.0	765.0
Investment in equity of consolidated subsidiaries		0.0	0.0
Restricted cash		3.0	0.0
Goodwill		2,092.0	4,716.0	$ 2,124.0
Indefinite-lived intangible assets		171.0	158.0	$ 158.0
Finite-lived intangible assets, net		5,624.0	7,977.0
Other long-term assets		1,452.0	841.0
Total assets	[1]	13,382.0	17,370.0
Accounts payable and accrued liabilities		533.0	782.0
Current portion of long-term debt		58.0	71.0
Other current liabilities		443.0	281.0
Total current liabilities		1,034.0	1,134.0
Notes payable, finance leases, and commercial bank financing, less current portion		12,493.0	12,367.0
Investment in deficit of consolidated subsidiaries		0.0
Other long-term liabilities		850.0	1,097.0
Total liabilities	[1]	14,377.0	14,598.0
Redeemable noncontrolling interests		190.0	1,078.0
Total Sinclair Broadcast Group equity		(1,274.0)	1,502.0
Noncontrolling interests		89.0	192.0
Total liabilities, redeemable noncontrolling interests, and equity		13,382.0	17,370.0
Reportable legal entities | Sinclair Broadcast Group, Inc.
Condensed Financial Statements, Captions [Line Items]
Cash and cash equivalents		0.0	0.0
Accounts receivable		0.0	0.0
Other current assets		7.0	5.0
Total current assets		7.0	5.0
Property and equipment, net		1.0	1.0
Investment in equity of consolidated subsidiaries		430.0	2,270.0
Restricted cash		0.0
Goodwill		0.0	0.0
Indefinite-lived intangible assets		0.0	0.0
Finite-lived intangible assets, net		0.0	0.0
Other long-term assets		139.0	82.0
Total assets		577.0	2,358.0
Accounts payable and accrued liabilities		19.0	142.0
Current portion of long-term debt		0.0	0.0
Other current liabilities		1.0	0.0
Total current liabilities		20.0	142.0
Notes payable, finance leases, and commercial bank financing, less current portion		700.0	700.0
Investment in deficit of consolidated subsidiaries		1,118.0
Other long-term liabilities		12.0	13.0
Total liabilities		1,850.0	855.0
Redeemable noncontrolling interests		0.0	0.0
Total Sinclair Broadcast Group equity		(1,273.0)	1,503.0
Noncontrolling interests		0.0	0.0
Total liabilities, redeemable noncontrolling interests, and equity		577.0	2,358.0
Reportable legal entities | Sinclair Television Group, Inc.
Condensed Financial Statements, Captions [Line Items]
Cash and cash equivalents		458.0	357.0
Accounts receivable		0.0	0.0
Other current assets		46.0	41.0
Total current assets		504.0	398.0
Property and equipment, net		33.0	31.0
Investment in equity of consolidated subsidiaries		3,549.0	3,558.0
Restricted cash		0.0
Goodwill		0.0	0.0
Indefinite-lived intangible assets		0.0	0.0
Finite-lived intangible assets, net		0.0	0.0
Other long-term assets		1,718.0	1,611.0
Total assets		5,804.0	5,598.0
Accounts payable and accrued liabilities		70.0	109.0
Current portion of long-term debt		13.0	27.0
Other current liabilities		2.0	1.0
Total current liabilities		85.0	137.0
Notes payable, finance leases, and commercial bank financing, less current portion		4,337.0	4,348.0
Investment in deficit of consolidated subsidiaries		0.0
Other long-term liabilities		121.0	53.0
Total liabilities		4,543.0	4,538.0
Redeemable noncontrolling interests		0.0	0.0
Total Sinclair Broadcast Group equity		1,261.0	1,060.0
Noncontrolling interests		0.0	0.0
Total liabilities, redeemable noncontrolling interests, and equity		5,804.0	5,598.0
Reportable legal entities | Guarantor Subsidiaries and KDSM, LLC
Condensed Financial Statements, Captions [Line Items]
Cash and cash equivalents		0.0	3.0
Accounts receivable		558.0	561.0
Other current assets		372.0	264.0
Total current assets		930.0	828.0
Property and equipment, net		706.0	659.0
Investment in equity of consolidated subsidiaries		0.0	0.0
Restricted cash		0.0
Goodwill		2,082.0	2,091.0
Indefinite-lived intangible assets		156.0	144.0
Finite-lived intangible assets, net		1,256.0	1,426.0
Other long-term assets		280.0	279.0
Total assets		5,410.0	5,427.0
Accounts payable and accrued liabilities		247.0	286.0
Current portion of long-term debt		5.0	4.0
Other current liabilities		134.0	133.0
Total current liabilities		386.0	423.0
Notes payable, finance leases, and commercial bank financing, less current portion		33.0	32.0
Investment in deficit of consolidated subsidiaries		0.0
Other long-term liabilities		1,445.0	1,418.0
Total liabilities		1,864.0	1,873.0
Redeemable noncontrolling interests		0.0	0.0
Total Sinclair Broadcast Group equity		3,546.0	3,554.0
Noncontrolling interests		0.0	0.0
Total liabilities, redeemable noncontrolling interests, and equity		5,410.0	5,427.0
Reportable legal entities | Non-Guarantor Subsidiaries
Condensed Financial Statements, Captions [Line Items]
Cash and cash equivalents		801.0	973.0
Accounts receivable		502.0	571.0
Other current assets		560.0	188.0
Total current assets		1,863.0	1,732.0
Property and equipment, net		109.0	96.0
Investment in equity of consolidated subsidiaries		0.0	0.0
Restricted cash		3.0
Goodwill		10.0	2,625.0
Indefinite-lived intangible assets		15.0	14.0
Finite-lived intangible assets, net		4,409.0	6,598.0
Other long-term assets		1,569.0	618.0
Total assets		7,978.0	11,683.0
Accounts payable and accrued liabilities		284.0	296.0
Current portion of long-term debt		41.0	41.0
Other current liabilities		306.0	147.0
Total current liabilities		631.0	484.0
Notes payable, finance leases, and commercial bank financing, less current portion		8,460.0	8,317.0
Investment in deficit of consolidated subsidiaries		0.0
Other long-term liabilities		710.0	547.0
Total liabilities		9,801.0	9,348.0
Redeemable noncontrolling interests		190.0	1,078.0
Total Sinclair Broadcast Group equity		(2,098.0)	1,069.0
Noncontrolling interests		85.0	188.0
Total liabilities, redeemable noncontrolling interests, and equity		7,978.0	11,683.0
Eliminations
Condensed Financial Statements, Captions [Line Items]
Cash and cash equivalents		0.0	0.0
Accounts receivable		0.0	0.0
Other current assets		(87.0)	(50.0)
Total current assets		(87.0)	(50.0)
Property and equipment, net		(26.0)	(22.0)
Investment in equity of consolidated subsidiaries		(3,979.0)	(5,828.0)
Restricted cash		0.0
Goodwill		0.0	0.0
Indefinite-lived intangible assets		0.0	0.0
Finite-lived intangible assets, net		(41.0)	(47.0)
Other long-term assets		(2,254.0)	(1,749.0)
Total assets		(6,387.0)	(7,696.0)
Accounts payable and accrued liabilities		(87.0)	(51.0)
Current portion of long-term debt		(1.0)	(1.0)
Other current liabilities		0.0	0.0
Total current liabilities		(88.0)	(52.0)
Notes payable, finance leases, and commercial bank financing, less current portion		(1,037.0)	(1,030.0)
Investment in deficit of consolidated subsidiaries		(1,118.0)
Other long-term liabilities		(1,438.0)	(934.0)
Total liabilities		(3,681.0)	(2,016.0)
Redeemable noncontrolling interests		0.0	0.0
Total Sinclair Broadcast Group equity		(2,710.0)	(5,684.0)
Noncontrolling interests		4.0	4.0
Total liabilities, redeemable noncontrolling interests, and equity		$ (6,387.0)	$ (7,696.0)

[1] Our consolidated total assets as of December 31, 2020 and 2019 include total assets of variable interest entities (VIEs) of $233 million and $228 million, respectively, which can only be used to settle the obligations of the VIEs.  Our consolidated total liabilities as of December 31, 2020 and 2019 include total liabilities of the VIEs of $60 million and $27 million, respectively, for which the creditors of the VIEs have no recourse to us.  See Note 14. Variable Interest Entities.