This item represents the net total realized and unrealized gain (loss) included in earnings for the period as a result of selling or holding marketable securities categorized as trading, available-for-sale, or held-to-maturity, including the unrealized holding gain (loss) of held-to-maturity securities transferred to the trading security category and the cumulative unrealized gain (loss) which was included in other comprehensive income (a separate component of shareholders' equity) for available-for-sale securities transferred to trading securities during the period. Additionally, this item would include any gains (losses) realized during the period from the sale of investments accounted for under the cost method of accounting and losses recognized for other than temporary impairments (OTTI) of the subject investments. Additionally, this item includes any gain (loss) on the sale or disposal of an equity method investment.

No definition available.

Quarterly Financial Data (Unaudited) (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended								12 Months Ended
	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2020	Mar. 31, 2019	Mar. 31, 2018
Schedule of Quarterly Financial Data [Line Items]
Revenues	$ 944.3	$ 998.5	$ 983.5	$ 963.6	$ 913.7	$ 933.2	$ 901.0	$ 932.7	$ 3,890.0	$ 3,680.5	$ 4,129.1
Operating income (loss)	(12.0)	(39.5)	57.6	(3.2)	(34.0)	86.8	39.1	38.2	2.8	130.0	248.7
Net income (loss)	(48.9)	(97.8)	(1.2)	(58.4)	(159.1)	20.1	(149.3)	(11.4)	(206.4)	(299.6)	468.1
Net income (loss) attributable to Lions Gate Entertainment Corp. shareholders	$ (44.9)	$ (91.2)	$ 1.8	$ (54.0)	$ (155.2)	$ 22.9	$ (144.1)	$ (7.9)	$ (188.4)	$ (284.2)	$ 473.6
Per share information attributable to Lions Gate Entertainment Corp. shareholders:
Basic net income (loss) per common share (in usd per share)	$ (0.20)	$ (0.42)	$ 0.01	$ (0.25)	$ (0.72)	$ 0.11	$ (0.67)	$ (0.04)	$ (0.86)	$ (1.33)	$ 2.27
Diluted net income (loss) per common share (in usd per share)	$ (0.20)	$ (0.42)	$ 0.01	$ (0.25)	$ (0.72)	$ 0.10	$ (0.67)	$ (0.04)	$ (0.86)	$ (1.33)	$ 2.15
Restructuring and other									$ 24.3	$ 78.0	$ 59.8
COVID-19 related costs	$ 50.2
Programming and content charges									76.5	35.1	0.0
Gain (loss) on extinguishment of debt									5.4	(1.9)	(35.7)
Shareholder litigation settlements									0.0	114.1	0.0
Gain (loss) on investments									$ (0.5)	$ (87.6)	$ 171.8
Operating Income (Loss) And Net Income (Loss)
Per share information attributable to Lions Gate Entertainment Corp. shareholders:
Restructuring and other	7.5	$ 3.7	$ 7.6	$ 5.6	$ 35.9	$ 16.6	$ 15.0	$ 10.5
Restructuring and other items, net of tax	5.7	2.7	5.7	4.3	27.3	12.6	11.5	7.8
COVID-19 related costs	50.2
COVID-10 related costs, net of tax	38.1
Programming and content charges	2.5	74.0			35.1
Programming and content charges, net of tax	1.9	56.1			26.7
Net income
Per share information attributable to Lions Gate Entertainment Corp. shareholders:
Gain (loss) on extinguishment of debt	6.7	(1.4)			(1.9)
Gain (loss) on extinguishment of debt, tax	5.1	(1.0)			(1.4)
Charge (benefit) from increases (decreases) in valuation allowance	$ 5.5	$ 11.5	$ (6.6)	$ 11.1	53.7
Shareholder litigation settlements							114.1
Shareholder litigation settlements, net of tax							104.7
Gain (loss) on investments					(44.4)	(6.2)	(36.1)	(0.9)
Gain ((loss) on investments, net of tax					$ (33.7)	$ (4.7)	$ (32.4)	$ (0.7)