Description of Business, Basis of Presentation and Significant Accounting Policies - Basic and Diluted Net Loss Per Common Share (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	12 Months Ended
	Mar. 31, 2025	Mar. 31, 2024	Mar. 31, 2023
Numerator:
Net loss attributable to Old Lions Gate Entertainment Corp. shareholders	$ (128.5)	$ (93.5)	$ (0.3)
Recovery (accretion) of redeemable noncontrolling interest	5.0	(11.9)	0.0
Net income (loss) attributable to Legacy Lionsgate Studios Corp. shareholders after accretion of redeemable noncontrolling interest, basic	(123.5)	(105.4)	(0.3)
Net income (loss) attributable to Legacy Lionsgate Studios Corp. shareholders after accretion of redeemable noncontrolling interest, diluted	$ (123.5)	$ (105.4)	$ (0.3)
Denominator:
Weighted average common shares outstanding, basic (in shares)	284.6	253.4	253.4
Weighted average common shares outstanding, diluted (in shares)	284.6	253.4	253.4
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.
Numerator:
Net loss attributable to Old Lions Gate Entertainment Corp. shareholders	$ (362.0)	$ (1,102.9)	$ (2,010.2)
Recovery (accretion) of redeemable noncontrolling interest	5.0	(11.9)	0.0
Net income (loss) attributable to Legacy Lionsgate Studios Corp. shareholders after accretion of redeemable noncontrolling interest, basic	(357.0)	(1,114.8)	(2,010.2)
Net income (loss) attributable to Legacy Lionsgate Studios Corp. shareholders after accretion of redeemable noncontrolling interest, diluted	$ (357.0)	$ (1,114.8)	$ (2,010.2)
Denominator:
Weighted average common shares outstanding, basic (in shares)	238.9	233.6	227.9
Weighted average common shares outstanding, diluted (in shares)	238.9	233.6	227.9
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)