Capital Stock - Stock Options Activity (Details) - Stock Options and SARs $ / shares in Units, shares in Millions, $ in Millions	12 Months Ended
	Mar. 31, 2025 USD ($) $ / shares shares
Old Lions Gate Class A Voting Shares
Number of Shares
Outstanding, beginning balance (in shares)	2.4
Granted (in shares)	0.0
Exercised (in shares)	0.0
Forfeited or expired (in shares)	(0.1)
Outstanding, ending balance (in shares)	2.3
Weighted-Average Exercise Price
Outstanding, beginning balance (in USD per share) | $ / shares	$ 22,960,000
Granted, weighted average exercise price (in USD per share) | $ / shares	0
Options exercised or restricted stock or RSUs vested, weighted average exercise price (in USD per share) | $ / shares	0
Forfeited or expired, weighted average exercise price (in USD per share) | $ / shares	20,260,000
Outstanding, ending balance (in USD per share) | $ / shares	$ 23,100,000
Weighted average remaining contractual term, outstanding	1 year 6 months 3 days
Intrinsic value, outstanding | $	$ 0.1
Number of shares, vested or expected to vest (in shares)	2.3
Weighted average exercise price, vested or expected to vest (in dollars per share) | $ / shares	$ 23,100,000
Aggregate intrinsic value, vested and expected to vest | $	$ 0.1
Number of shares exercisable, (in shares)	2.3
Weighted average exercise price (in dollars per share) | $ / shares	$ 23,100,000
Weighted average remaining contractual term, exercisable	1 year 6 months 3 days
Intrinsic value, exercisable | $	$ 0.1
Old Lions Gate Class A Voting Shares | Lions Gate Entertainment Corp.
Number of Shares
Outstanding, beginning balance (in shares)	2.4
Granted (in shares)	0.0
Exercised (in shares)	0.0
Forfeited or expired (in shares)	(0.1)
Outstanding, ending balance (in shares)	2.3
Weighted-Average Exercise Price
Outstanding, beginning balance (in USD per share) | $ / shares	$ 22.96
Granted, weighted average exercise price (in USD per share) | $ / shares	0
Options exercised or restricted stock or RSUs vested, weighted average exercise price (in USD per share) | $ / shares	0
Forfeited or expired, weighted average exercise price (in USD per share) | $ / shares	20.26
Outstanding, ending balance (in USD per share) | $ / shares	$ 23.09
Weighted average remaining contractual term, outstanding	1 year 6 months 7 days
Intrinsic value, outstanding | $	$ 0.1
Number of shares, vested or expected to vest (in shares)	2.3
Weighted average exercise price, vested or expected to vest (in dollars per share) | $ / shares	$ 23.09
Weighted average remaining contractual term, vested and expected to vest	1 year 6 months 7 days
Aggregate intrinsic value, vested and expected to vest | $	$ 0.1
Number of shares exercisable, (in shares)	2.3
Weighted average exercise price (in dollars per share) | $ / shares	$ 23.09
Weighted average remaining contractual term, exercisable	1 year 6 months 7 days
Intrinsic value, exercisable | $	$ 0.1
Old Lions Gate Class B Non-Voting Shares
Number of Shares
Outstanding, beginning balance (in shares)	17.1
Granted (in shares)	0.0
Exercised (in shares)	(0.1)
Forfeited or expired (in shares)	(2.2)
Outstanding, ending balance (in shares)	14.8
Weighted-Average Exercise Price
Outstanding, beginning balance (in USD per share) | $ / shares	$ 13,920,000
Granted, weighted average exercise price (in USD per share) | $ / shares	7,120,000
Options exercised or restricted stock or RSUs vested, weighted average exercise price (in USD per share) | $ / shares	5,500,000
Forfeited or expired, weighted average exercise price (in USD per share) | $ / shares	14,640,000
Outstanding, ending balance (in USD per share) | $ / shares	$ 13,860,000
Weighted average remaining contractual term, outstanding	4 years 2 months 19 days
Intrinsic value, outstanding | $	$ 0.6
Number of shares, vested or expected to vest (in shares)	14.8
Weighted average exercise price, vested or expected to vest (in dollars per share) | $ / shares	$ 13,870,000
Weighted average remaining contractual term, vested and expected to vest	4 years 2 months 15 days
Aggregate intrinsic value, vested and expected to vest | $	$ 0.6
Number of shares exercisable, (in shares)	14.5
Weighted average exercise price (in dollars per share) | $ / shares	$ 13,980,000
Weighted average remaining contractual term, exercisable	4 years 1 month 20 days
Intrinsic value, exercisable | $	$ 0.6
Old Lions Gate Class B Non-Voting Shares | Lions Gate Entertainment Corp.
Number of Shares
Outstanding, beginning balance (in shares)	18.3
Granted (in shares)	0.0
Exercised (in shares)	(0.1)
Forfeited or expired (in shares)	(2.2)
Outstanding, ending balance (in shares)	16.0
Weighted-Average Exercise Price
Outstanding, beginning balance (in USD per share) | $ / shares	$ 13.73
Granted, weighted average exercise price (in USD per share) | $ / shares	7.12
Options exercised or restricted stock or RSUs vested, weighted average exercise price (in USD per share) | $ / shares	5.86
Forfeited or expired, weighted average exercise price (in USD per share) | $ / shares	14.67
Outstanding, ending balance (in USD per share) | $ / shares	$ 13.66
Weighted average remaining contractual term, outstanding	4 years 2 months 8 days
Intrinsic value, outstanding | $	$ 0.7
Number of shares, vested or expected to vest (in shares)	15.9
Weighted average exercise price, vested or expected to vest (in dollars per share) | $ / shares	$ 13.67
Weighted average remaining contractual term, vested and expected to vest	4 years 2 months 4 days
Aggregate intrinsic value, vested and expected to vest | $	$ 0.7
Number of shares exercisable, (in shares)	15.6
Weighted average exercise price (in dollars per share) | $ / shares	$ 13.77
Weighted average remaining contractual term, exercisable	4 years 1 month 13 days
Intrinsic value, exercisable | $	$ 0.7
Maximum | Old Lions Gate Class B Non-Voting Shares
Number of Shares
Granted (in shares)	0.1
Maximum | Old Lions Gate Class B Non-Voting Shares | Lions Gate Entertainment Corp.
Number of Shares
Exercised (in shares)	(0.1)