Goodwill and Intangible Assets - Narrative (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended	12 Months Ended
	Sep. 30, 2024	Mar. 31, 2025	Mar. 31, 2024	Mar. 31, 2023	Sep. 30, 2023
Goodwill [Line Items]
Amortization of intangible assets		$ 4.9	$ 5.3	$ 5.7
Estimated amortization expense, year ended March 31, 2026		3.3
Estimated amortization expense, year ended March 31, 2027		3.0
Estimated amortization expense, year ended March 31, 2028		3.0
Estimated amortization expense, year ended March 31, 2029		2.7
Estimated amortization expense, year ended March 31, 2030		2.1
Impairment, Intangible Asset, Indefinite-Lived (Excluding Goodwill), Statement of Income or Comprehensive Income [Extensible Enumeration]			Goodwill and intangible asset impairment
Amortization		$ 17.8	$ 15.6	$ 17.9
Basic net income (loss) per common share (in dollars per share)		$ (0.43)	$ (0.42)	$ 0.00
Diluted net income (loss) per common share (in dollars per share)		$ (0.43)	$ (0.42)	$ 0.00
Lions Gate Entertainment Corp.
Goodwill [Line Items]
Amortization of intangible assets		$ 155.1	$ 142.3	$ 140.2
Estimated amortization expense, year ended March 31, 2026		165.0
Estimated amortization expense, year ended March 31, 2027		152.6
Estimated amortization expense, year ended March 31, 2028		142.6
Estimated amortization expense, year ended March 31, 2029		133.8
Estimated amortization expense, year ended March 31, 2030		125.7
Impairment of Starz trade name intangible asset	$ 170.0
Finite-lived intangible asset, useful life					10 years
Amortization		$ 188.1	$ 192.2	$ 180.3
Basic net income (loss) per common share (in dollars per share)		$ (1.49)	$ (4.77)	$ (8.82)
Diluted net income (loss) per common share (in dollars per share)		$ (1.49)	$ (4.77)	$ (8.82)
Intangible Assets, Amortization Period | Lions Gate Entertainment Corp.
Goodwill [Line Items]
Amortization		$ 8.3	$ 4.0
Basic net income (loss) per common share (in dollars per share)		$ 0.03	$ 0.02
Diluted net income (loss) per common share (in dollars per share)		$ 0.03	$ 0.02
Trade Names | Lions Gate Entertainment Corp.
Goodwill [Line Items]
Indefinite-lived intangible assets (excluding goodwill)					$ 80.0