Net Income (Loss) Per Share (Basic) (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended		6 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Numerator:
Net income (loss) attributable to Lions Gate Entertainment Corp. shareholders	$ (144.1)	$ 15.5	$ (151.9)	$ 189.3
Denominator:
Weighted average common shares outstanding (in shares)	213.6	207.8	212.7	207.3
Basic net income (loss) per common share (in usd per share)	$ (0.67)	$ 0.07	$ (0.71)	$ 0.91