Related Party Transactions - Narrative (Details) $ in Millions		12 Months Ended
	May 09, 2024 USD ($)	Mar. 31, 2025 USD ($) shares	Mar. 31, 2024 USD ($)	Mar. 31, 2023 USD ($)	May 06, 2025 shares	May 13, 2024 shares
Related Party Transaction [Line Items]
General and administration | $		$ 344.6	$ 349.2	$ 387.0
Revenue | $		3,195.5	2,986.4	3,083.8
Deferred revenue | $		$ 235.5	170.6
Common stock, shares outstanding (in shares) | shares						288,681,224
SEAC Sponsor Options
Related Party Transaction [Line Items]
Common stock, exercisable (in shares) | shares						2,177,191
Ignite, LLC | Vice Chair and Director, Mr. Burns
Related Party Transaction [Line Items]
Related party transaction, ownership interest		0.6545
Ignite, LLC | Director, Hardwick Simmons
Related Party Transaction [Line Items]
Related party transaction, ownership interest		0.2424
Corporate
Related Party Transaction [Line Items]
Corporate general and administrative expenses | $		$ (120.9)	(110.6)	(100.9)
Related Party
Related Party Transaction [Line Items]
Amounts of transaction | $		0.2	0.3	0.4
Revenue | $		619.7	545.9	775.5
Deferred revenue | $		$ 19.1
Common stock held by related parties (in shares) | shares		8,192,246
Common stock held by related parties (in percent)		7.00%
Related Party | Subsequent Event
Related Party Transaction [Line Items]
Voting ownership, percentage					18.50%
Related Party | Lionsgate Corporate
Related Party Transaction [Line Items]
General and administration | $		$ 120.9
Liberty Global Ventures Limited and Liberty Global Ltd. | Subsequent Event
Related Party Transaction [Line Items]
Common stock held by related parties (in shares) | shares					5,713,774
Common stock held by related parties (in percent)					2.00%
MHR Fund Management LLC | Subsequent Event
Related Party Transaction [Line Items]
Common stock held by related parties (in shares) | shares					28,568,868
Common stock held by related parties (in percent)					10.00%
General and Administrative Expenses Allocated to Parent | Related Party
Related Party Transaction [Line Items]
Amounts of transaction | $	$ 10.0
Investor Rights Agreement | Related Party | Subsequent Event
Related Party Transaction [Line Items]
Common stock, shares outstanding (in shares) | shares					10,000,000
Investor Rights Agreement, Three Designees | Related Party | Subsequent Event | Minimum
Related Party Transaction [Line Items]
Common stock, shares outstanding (in shares) | shares					7,500,000
Investor Rights Agreement, Three Designees | Related Party | Subsequent Event | Maximum
Related Party Transaction [Line Items]
Common stock, shares outstanding (in shares) | shares					10,000,000
Investor Rights Agreement, Two Designees | Related Party | Subsequent Event | Minimum
Related Party Transaction [Line Items]
Common stock, shares outstanding (in shares) | shares					5,000,000
Investor Rights Agreement, Two Designees | Related Party | Subsequent Event | Maximum
Related Party Transaction [Line Items]
Common stock, shares outstanding (in shares) | shares					7,500,000
Investor Rights Agreement, One Designee | Related Party | Subsequent Event | Minimum
Related Party Transaction [Line Items]
Common stock, shares outstanding (in shares) | shares					5,000,000
Corporate Expense Allocation Excluding Share-Based Compensation | Corporate
Related Party Transaction [Line Items]
Corporate general and administrative expenses | $		(14.2)	$ (110.6)	$ (100.9)
Expenses Allocated After Separation | Related Party | Lionsgate Corporate
Related Party Transaction [Line Items]
General and administration | $		$ 106.7