Goodwill and Intangible Assets - Finite-Lived Intangible Assets (Details) - USD ($) $ in Millions	Mar. 31, 2025	Mar. 31, 2024
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	$ 62.5	$ 62.5
Accumulated Amortization	41.7	36.8
Net Carrying Amount	20.8	25.7
Lions Gate Entertainment Corp.
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	1,963.5	1,963.5
Accumulated Amortization	1,126.7	971.7
Net Carrying Amount	836.8	991.8
Customer Relationships
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	31.0	31.0
Accumulated Amortization	14.1	12.1
Net Carrying Amount	16.9	18.9
Customer Relationships | Lions Gate Entertainment Corp.
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	1,852.0	1,852.0
Accumulated Amortization	1,087.1	942.9
Net Carrying Amount	764.9	909.1
Trademarks and Trade Names
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	7.6	7.6
Accumulated Amortization	4.0	3.0
Net Carrying Amount	3.6	4.6
Trademarks and Trade Names | Lions Gate Entertainment Corp.
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	87.6	87.6
Accumulated Amortization	16.0	7.1
Net Carrying Amount	71.6	80.5
Other Intangible Assets
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	23.9	23.9
Accumulated Amortization	23.6	21.7
Net Carrying Amount	0.3	2.2
Other Intangible Assets | Lions Gate Entertainment Corp.
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	23.9	23.9
Accumulated Amortization	23.6	21.7
Net Carrying Amount	$ 0.3	$ 2.2