Fair Value Measurements - Schedule of Carrying Values and Fair Values of Company’s Outstanding Debt, Film Related Obligations, and Interest Rate Swaps (Details) - USD ($) $ in Millions	Mar. 31, 2025	Mar. 31, 2024
Intercompany Revolver | Carrying Value | Revolving Credit Facility
Fair Value, Carrying Values and Fair Values of Assets and Liabilities Not Required to be Carried at Fair Value on a Recurring Basis [Line Items]
Line of credit facility, fair value disclosure	$ 81.6	$ 0.0
Intercompany Revolver | Fair Value | Revolving Credit Facility | Level 2
Fair Value, Carrying Values and Fair Values of Assets and Liabilities Not Required to be Carried at Fair Value on a Recurring Basis [Line Items]
Line of credit facility, fair value disclosure	81.6	0.0
LGTV Revolver | Carrying Value | Revolving Credit Facility
Fair Value, Carrying Values and Fair Values of Assets and Liabilities Not Required to be Carried at Fair Value on a Recurring Basis [Line Items]
Line of credit facility, fair value disclosure	0.0	569.9
LGTV Revolver | Fair Value | Revolving Credit Facility | Level 2
Fair Value, Carrying Values and Fair Values of Assets and Liabilities Not Required to be Carried at Fair Value on a Recurring Basis [Line Items]
Line of credit facility, fair value disclosure	0.0	575.0
LGTV Term Loan A | Carrying Value | Term Loans
Fair Value, Carrying Values and Fair Values of Assets and Liabilities Not Required to be Carried at Fair Value on a Recurring Basis [Line Items]
Loans, fair value disclosure	313.4	396.6
LGTV Term Loan A | Fair Value | Term Loans | Level 2
Fair Value, Carrying Values and Fair Values of Assets and Liabilities Not Required to be Carried at Fair Value on a Recurring Basis [Line Items]
Loans, fair value disclosure	312.9	397.3
LGTV Term Loan B | Carrying Value | Term Loans
Fair Value, Carrying Values and Fair Values of Assets and Liabilities Not Required to be Carried at Fair Value on a Recurring Basis [Line Items]
Loans, fair value disclosure	0.0	816.9
LGTV Term Loan B | Fair Value | Term Loans | Level 2
Fair Value, Carrying Values and Fair Values of Assets and Liabilities Not Required to be Carried at Fair Value on a Recurring Basis [Line Items]
Loans, fair value disclosure	0.0	818.1
eOne IP Credit Facility | Carrying Value | Line of Credit
Fair Value, Carrying Values and Fair Values of Assets and Liabilities Not Required to be Carried at Fair Value on a Recurring Basis [Line Items]
Line of credit facility, fair value disclosure	317.6	0.0
eOne IP Credit Facility | Fair Value | Line of Credit | Level 2
Fair Value, Carrying Values and Fair Values of Assets and Liabilities Not Required to be Carried at Fair Value on a Recurring Basis [Line Items]
Line of credit facility, fair value disclosure	323.0	0.0
LG IP Credit Facility | Carrying Value | Line of Credit
Fair Value, Carrying Values and Fair Values of Assets and Liabilities Not Required to be Carried at Fair Value on a Recurring Basis [Line Items]
Line of credit facility, fair value disclosure	962.9	0.0
LG IP Credit Facility | Fair Value | Line of Credit | Level 2
Fair Value, Carrying Values and Fair Values of Assets and Liabilities Not Required to be Carried at Fair Value on a Recurring Basis [Line Items]
Line of credit facility, fair value disclosure	978.8	0.0
Production Loans | Carrying Value | Production Loans
Fair Value, Carrying Values and Fair Values of Assets and Liabilities Not Required to be Carried at Fair Value on a Recurring Basis [Line Items]
Loans, fair value disclosure	1,394.1	1,286.2
Production Loans | Fair Value | Production Loans | Level 2
Fair Value, Carrying Values and Fair Values of Assets and Liabilities Not Required to be Carried at Fair Value on a Recurring Basis [Line Items]
Loans, fair value disclosure	1,395.4	1,292.2
Production Tax Credit Facility | Carrying Value | Line of Credit
Fair Value, Carrying Values and Fair Values of Assets and Liabilities Not Required to be Carried at Fair Value on a Recurring Basis [Line Items]
Line of credit facility, fair value disclosure	276.2	258.7
Production Tax Credit Facility | Fair Value | Line of Credit | Level 2
Fair Value, Carrying Values and Fair Values of Assets and Liabilities Not Required to be Carried at Fair Value on a Recurring Basis [Line Items]
Line of credit facility, fair value disclosure	280.0	260.0
Backlog Facility and Other | Carrying Value | Secured Debt
Fair Value, Carrying Values and Fair Values of Assets and Liabilities Not Required to be Carried at Fair Value on a Recurring Basis [Line Items]
Backlog Facility and Other, IP Credit Facility and Financing component of interest rate swaps, fair value disclosure	238.4	285.4
Backlog Facility and Other | Fair Value | Secured Debt | Level 2
Fair Value, Carrying Values and Fair Values of Assets and Liabilities Not Required to be Carried at Fair Value on a Recurring Basis [Line Items]
Backlog Facility and Other, IP Credit Facility and Financing component of interest rate swaps, fair value disclosure	238.9	287.3
Film Library Facility | Carrying Value | Secured Debt
Fair Value, Carrying Values and Fair Values of Assets and Liabilities Not Required to be Carried at Fair Value on a Recurring Basis [Line Items]
Backlog Facility and Other, IP Credit Facility and Financing component of interest rate swaps, fair value disclosure	74.4	107.6
Film Library Facility | Fair Value | Secured Debt | Level 2
Fair Value, Carrying Values and Fair Values of Assets and Liabilities Not Required to be Carried at Fair Value on a Recurring Basis [Line Items]
Backlog Facility and Other, IP Credit Facility and Financing component of interest rate swaps, fair value disclosure	$ 75.9	$ 109.9