FAIR VALUE MEASUREMENTS - Schedule of Carrying Value and Fair Value of Notes and Debentures (Details) - USD ($) $ in Millions	Oct. 31, 2025	Sep. 30, 2025	Jun. 30, 2025	Dec. 31, 2024	Sep. 30, 2024
FAIR VALUE MEASUREMENTS:
Debt discount and deferred financing costs		$ 56.0		$ 36.0
Interest Rate Swap
FAIR VALUE MEASUREMENTS:
Derivative liability		$ 0.1
Derivative asset				1.0
Senior Notes | STG Second Lien Secured Notes 9.750 Percent Due 2033
FAIR VALUE MEASUREMENTS:
Interest rate (as a percent)		9.75%
Senior Notes | STG Senior Unsecured Notes 8.125 Percent Due 2027
FAIR VALUE MEASUREMENTS:
Interest rate (as a percent)		8.125%
Senior Notes | 5.500% Senior Notes due 2030
FAIR VALUE MEASUREMENTS:
Interest rate (as a percent)		5.50%
Senior Notes | STG 5.125% Senior Notes
FAIR VALUE MEASUREMENTS:
Interest rate (as a percent)		5.125%
Debt instrument, repurchased aggregate principal amount			$ 81.0
Senior Notes | STG 5.125% Senior Notes | Subsequent Event
FAIR VALUE MEASUREMENTS:
Debt instrument, repurchased aggregate principal amount	$ 89.0
Senior Notes | STG Second-Out First Lien Secured Notes 4.375 Percent due 2032
FAIR VALUE MEASUREMENTS:
Interest rate (as a percent)		4.375%
Senior Notes | 4.125% Senior Secured Notes due 2030
FAIR VALUE MEASUREMENTS:
Interest rate (as a percent)		4.125%
Term Loan | Term Loan B-2, due September 30, 2026
FAIR VALUE MEASUREMENTS:
Debt instrument, repurchased aggregate principal amount					$ 27.0
Level 1 | Fair Value | Money market funds
FAIR VALUE MEASUREMENTS:
Money market funds		$ 378.0		601.0
Level 2 | Face Value | Debt of variable interest entities
FAIR VALUE MEASUREMENTS:
Debt fair value disclosure		6.0		7.0
Level 2 | Face Value | Senior Notes | STG Second Lien Secured Notes 9.750 Percent Due 2033
FAIR VALUE MEASUREMENTS:
Debt fair value disclosure		432.0		0.0
Level 2 | Face Value | Senior Notes | STG Senior Unsecured Notes 8.125 Percent Due 2027
FAIR VALUE MEASUREMENTS:
Debt fair value disclosure		1,430.0		0.0
Level 2 | Face Value | Senior Notes | 5.500% Senior Notes due 2030
FAIR VALUE MEASUREMENTS:
Debt fair value disclosure		485.0		485.0
Level 2 | Face Value | Senior Notes | STG 5.125% Senior Notes
FAIR VALUE MEASUREMENTS:
Debt fair value disclosure		89.0		274.0
Level 2 | Face Value | Senior Notes | STG Second-Out First Lien Secured Notes 4.375 Percent due 2032
FAIR VALUE MEASUREMENTS:
Debt fair value disclosure		238.0		0.0
Level 2 | Face Value | Senior Notes | 4.125% Senior Secured Notes due 2030
FAIR VALUE MEASUREMENTS:
Debt fair value disclosure		0.0		737.0
Level 2 | Face Value | Term Loan | Term Loan B-2, due September 30, 2026
FAIR VALUE MEASUREMENTS:
Debt fair value disclosure		0.0		1,175.0
Level 2 | Face Value | Term Loan | Term Loan B-3, due April 1, 2028
FAIR VALUE MEASUREMENTS:
Debt fair value disclosure		3.0		714.0
Level 2 | Face Value | Term Loan | Term Loan B-4, due April 21, 2029
FAIR VALUE MEASUREMENTS:
Debt fair value disclosure		0.0		731.0
Level 2 | Face Value | Term Loan | Term Loan B-6, due December 31, 2029
FAIR VALUE MEASUREMENTS:
Debt fair value disclosure		708.0		0.0
Level 2 | Face Value | Term Loan | Term Loan B-7, due December 31, 2030
FAIR VALUE MEASUREMENTS:
Debt fair value disclosure		728.0		0.0
Level 2 | Fair Value | Debt of variable interest entities
FAIR VALUE MEASUREMENTS:
Debt fair value disclosure		6.0		7.0
Level 2 | Fair Value | Senior Notes | STG Second Lien Secured Notes 9.750 Percent Due 2033
FAIR VALUE MEASUREMENTS:
Debt fair value disclosure		472.0		0.0
Level 2 | Fair Value | Senior Notes | STG Senior Unsecured Notes 8.125 Percent Due 2027
FAIR VALUE MEASUREMENTS:
Debt fair value disclosure		1,472.0		0.0
Level 2 | Fair Value | Senior Notes | 5.500% Senior Notes due 2030
FAIR VALUE MEASUREMENTS:
Debt fair value disclosure		415.0		328.0
Level 2 | Fair Value | Senior Notes | STG 5.125% Senior Notes
FAIR VALUE MEASUREMENTS:
Debt fair value disclosure		89.0		249.0
Level 2 | Fair Value | Senior Notes | STG Second-Out First Lien Secured Notes 4.375 Percent due 2032
FAIR VALUE MEASUREMENTS:
Debt fair value disclosure		171.0		0.0
Level 2 | Fair Value | Senior Notes | 4.125% Senior Secured Notes due 2030
FAIR VALUE MEASUREMENTS:
Debt fair value disclosure		0.0		546.0
Level 2 | Fair Value | Term Loan | Term Loan B-2, due September 30, 2026
FAIR VALUE MEASUREMENTS:
Debt fair value disclosure		0.0		1,160.0
Level 2 | Fair Value | Term Loan | Term Loan B-3, due April 1, 2028
FAIR VALUE MEASUREMENTS:
Debt fair value disclosure		2.0		575.0
Level 2 | Fair Value | Term Loan | Term Loan B-4, due April 21, 2029
FAIR VALUE MEASUREMENTS:
Debt fair value disclosure		0.0		589.0
Level 2 | Fair Value | Term Loan | Term Loan B-6, due December 31, 2029
FAIR VALUE MEASUREMENTS:
Debt fair value disclosure		630.0		0.0
Level 2 | Fair Value | Term Loan | Term Loan B-7, due December 31, 2030
FAIR VALUE MEASUREMENTS:
Debt fair value disclosure		648.0		0.0
Level 2 | Fair Value | Interest Rate Swap
FAIR VALUE MEASUREMENTS:
Derivative liability		0.0
Derivative asset				1.0
Sinclair Broadcast Group, LLC
FAIR VALUE MEASUREMENTS:
Debt discount and deferred financing costs		56.0		36.0
Sinclair Broadcast Group, LLC | Interest Rate Swap
FAIR VALUE MEASUREMENTS:
Derivative liability		$ 0.1
Derivative asset				1.0
Sinclair Broadcast Group, LLC | Senior Notes | STG Second Lien Secured Notes 9.750 Percent Due 2033
FAIR VALUE MEASUREMENTS:
Interest rate (as a percent)		9.75%
Sinclair Broadcast Group, LLC | Senior Notes | STG Senior Unsecured Notes 8.125 Percent Due 2027
FAIR VALUE MEASUREMENTS:
Interest rate (as a percent)		8.125%
Sinclair Broadcast Group, LLC | Senior Notes | 5.500% Senior Notes due 2030
FAIR VALUE MEASUREMENTS:
Interest rate (as a percent)		5.50%
Sinclair Broadcast Group, LLC | Senior Notes | STG 5.125% Senior Notes
FAIR VALUE MEASUREMENTS:
Interest rate (as a percent)		5.125%
Debt instrument, repurchased aggregate principal amount			$ 81.0
Sinclair Broadcast Group, LLC | Senior Notes | STG 5.125% Senior Notes | Subsequent Event
FAIR VALUE MEASUREMENTS:
Debt instrument, repurchased aggregate principal amount	$ 89.0
Sinclair Broadcast Group, LLC | Senior Notes | STG Second-Out First Lien Secured Notes 4.375 Percent due 2032
FAIR VALUE MEASUREMENTS:
Interest rate (as a percent)		4.375%
Sinclair Broadcast Group, LLC | Senior Notes | 4.125% Senior Secured Notes due 2030
FAIR VALUE MEASUREMENTS:
Interest rate (as a percent)		4.125%
Sinclair Broadcast Group, LLC | Senior Notes | 4.125% Unsecured Notes due 2030
FAIR VALUE MEASUREMENTS:
Interest rate (as a percent)		4.125%
Sinclair Broadcast Group, LLC | Term Loan | Term Loan B-2, due September 30, 2026
FAIR VALUE MEASUREMENTS:
Debt instrument, repurchased aggregate principal amount					$ 27.0
Sinclair Broadcast Group, LLC | Level 1 | Fair Value | Money market funds
FAIR VALUE MEASUREMENTS:
Money market funds		$ 103.0		253.0
Sinclair Broadcast Group, LLC | Level 2 | Face Value | Debt of variable interest entities
FAIR VALUE MEASUREMENTS:
Debt fair value disclosure		6.0		7.0
Sinclair Broadcast Group, LLC | Level 2 | Face Value | Senior Notes | STG Second Lien Secured Notes 9.750 Percent Due 2033
FAIR VALUE MEASUREMENTS:
Debt fair value disclosure		432.0		0.0
Sinclair Broadcast Group, LLC | Level 2 | Face Value | Senior Notes | STG Senior Unsecured Notes 8.125 Percent Due 2027
FAIR VALUE MEASUREMENTS:
Debt fair value disclosure		1,430.0		0.0
Sinclair Broadcast Group, LLC | Level 2 | Face Value | Senior Notes | 5.500% Senior Notes due 2030
FAIR VALUE MEASUREMENTS:
Debt fair value disclosure		485.0		485.0
Sinclair Broadcast Group, LLC | Level 2 | Face Value | Senior Notes | STG 5.125% Senior Notes
FAIR VALUE MEASUREMENTS:
Debt fair value disclosure		89.0		274.0
Sinclair Broadcast Group, LLC | Level 2 | Face Value | Senior Notes | STG Second-Out First Lien Secured Notes 4.375 Percent due 2032
FAIR VALUE MEASUREMENTS:
Debt fair value disclosure		238.0		0.0
Sinclair Broadcast Group, LLC | Level 2 | Face Value | Senior Notes | 4.125% Senior Secured Notes due 2030
FAIR VALUE MEASUREMENTS:
Debt fair value disclosure		0.0		737.0
Sinclair Broadcast Group, LLC | Level 2 | Face Value | Senior Notes | 4.125% Unsecured Notes due 2030
FAIR VALUE MEASUREMENTS:
Debt fair value disclosure		4.0		0.0
Sinclair Broadcast Group, LLC | Level 2 | Face Value | Term Loan | Term Loan B-2, due September 30, 2026
FAIR VALUE MEASUREMENTS:
Debt fair value disclosure		0.0		1,175.0
Sinclair Broadcast Group, LLC | Level 2 | Face Value | Term Loan | Term Loan B-3, due April 1, 2028
FAIR VALUE MEASUREMENTS:
Debt fair value disclosure		3.0		714.0
Sinclair Broadcast Group, LLC | Level 2 | Face Value | Term Loan | Term Loan B-4, due April 21, 2029
FAIR VALUE MEASUREMENTS:
Debt fair value disclosure		0.0		731.0
Sinclair Broadcast Group, LLC | Level 2 | Face Value | Term Loan | Term Loan B-6, due December 31, 2029
FAIR VALUE MEASUREMENTS:
Debt fair value disclosure		708.0		0.0
Sinclair Broadcast Group, LLC | Level 2 | Face Value | Term Loan | Term Loan B-7, due December 31, 2030
FAIR VALUE MEASUREMENTS:
Debt fair value disclosure		728.0		0.0
Sinclair Broadcast Group, LLC | Level 2 | Fair Value | Debt of variable interest entities
FAIR VALUE MEASUREMENTS:
Debt fair value disclosure		6.0		7.0
Sinclair Broadcast Group, LLC | Level 2 | Fair Value | Senior Notes | STG Second Lien Secured Notes 9.750 Percent Due 2033
FAIR VALUE MEASUREMENTS:
Debt fair value disclosure		472.0		0.0
Sinclair Broadcast Group, LLC | Level 2 | Fair Value | Senior Notes | STG Senior Unsecured Notes 8.125 Percent Due 2027
FAIR VALUE MEASUREMENTS:
Debt fair value disclosure		1,472.0		0.0
Sinclair Broadcast Group, LLC | Level 2 | Fair Value | Senior Notes | 5.500% Senior Notes due 2030
FAIR VALUE MEASUREMENTS:
Debt fair value disclosure		415.0		328.0
Sinclair Broadcast Group, LLC | Level 2 | Fair Value | Senior Notes | STG 5.125% Senior Notes
FAIR VALUE MEASUREMENTS:
Debt fair value disclosure		89.0		249.0
Sinclair Broadcast Group, LLC | Level 2 | Fair Value | Senior Notes | STG Second-Out First Lien Secured Notes 4.375 Percent due 2032
FAIR VALUE MEASUREMENTS:
Debt fair value disclosure		171.0		0.0
Sinclair Broadcast Group, LLC | Level 2 | Fair Value | Senior Notes | 4.125% Senior Secured Notes due 2030
FAIR VALUE MEASUREMENTS:
Debt fair value disclosure		0.0		546.0
Sinclair Broadcast Group, LLC | Level 2 | Fair Value | Senior Notes | 4.125% Unsecured Notes due 2030
FAIR VALUE MEASUREMENTS:
Debt fair value disclosure		3.0		0.0
Sinclair Broadcast Group, LLC | Level 2 | Fair Value | Term Loan | Term Loan B-2, due September 30, 2026
FAIR VALUE MEASUREMENTS:
Debt fair value disclosure		0.0		1,160.0
Sinclair Broadcast Group, LLC | Level 2 | Fair Value | Term Loan | Term Loan B-3, due April 1, 2028
FAIR VALUE MEASUREMENTS:
Debt fair value disclosure		2.0		575.0
Sinclair Broadcast Group, LLC | Level 2 | Fair Value | Term Loan | Term Loan B-4, due April 21, 2029
FAIR VALUE MEASUREMENTS:
Debt fair value disclosure		0.0		589.0
Sinclair Broadcast Group, LLC | Level 2 | Fair Value | Term Loan | Term Loan B-6, due December 31, 2029
FAIR VALUE MEASUREMENTS:
Debt fair value disclosure		630.0		0.0
Sinclair Broadcast Group, LLC | Level 2 | Fair Value | Term Loan | Term Loan B-7, due December 31, 2030
FAIR VALUE MEASUREMENTS:
Debt fair value disclosure		648.0		0.0
Sinclair Broadcast Group, LLC | Level 2 | Fair Value | Interest Rate Swap
FAIR VALUE MEASUREMENTS:
Derivative liability		$ 0.0
Derivative asset				$ 1.0