Net Income (Loss) Per Share (Basic) (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended		6 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Numerator:
Net income (loss) attributable to Lions Gate Entertainment Corp. shareholders	$ (18.4)	$ 1.8	$ 32.7	$ (52.2)
Denominator:
Weighted average common shares outstanding (in shares)	220.4	217.5	220.0	216.8
Basic net income (loss) per common share (in usd per share)	$ (0.08)	$ 0.01	$ 0.15	$ (0.24)