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LONG-TERM DEBT - Schedule of Long-Term Debt (Details) - USD ($) $ in Thousands	Dec. 31, 2023	Mar. 31, 2023	Dec. 31, 2022	Mar. 31, 2021
Debt Instrument [Line Items]
Long term debt	$ 6,371,852		$ 8,761,189
Less: Premiums, discounts, and unamortized debt issuance costs, net	(28,042)		(41,899)
Long-term debt	6,343,810		8,719,290
Less: Current portion	0		(1,286,473)
Long-term debt, net	$ 6,343,810		7,432,817
6% senior notes, due 2023
Debt Instrument [Line Items]
Long-term debt, interest rate (in percent)	6.00%	6.00%
Senior notes	$ 0		1,250,000
5.375% MGM China senior notes, due 2024
Debt Instrument [Line Items]
Long-term debt, interest rate (in percent)	5.375%
Senior notes	$ 750,000		750,000
6.75% senior notes, due 2025
Debt Instrument [Line Items]
Long-term debt, interest rate (in percent)	6.75%
Senior notes	$ 750,000		750,000
5.75% senior notes, due 2025
Debt Instrument [Line Items]
Long-term debt, interest rate (in percent)	5.75%
Senior notes	$ 675,000		675,000
5.25% MGM China senior notes, due 2025
Debt Instrument [Line Items]
Long-term debt, interest rate (in percent)	5.25%
Senior notes	$ 500,000		500,000
5.875% MGM China senior notes, due 2026
Debt Instrument [Line Items]
Long-term debt, interest rate (in percent)	5.875%
Senior notes	$ 750,000		750,000
4.625% senior notes, due 2026
Debt Instrument [Line Items]
Long-term debt, interest rate (in percent)	4.625%
Senior notes	$ 400,000		400,000
5.5% senior notes, due 2027
Debt Instrument [Line Items]
Long-term debt, interest rate (in percent)	5.50%
Senior notes	$ 675,000		675,000
4.75% MGM China senior notes, due 2027
Debt Instrument [Line Items]
Long-term debt, interest rate (in percent)	4.75%			4.75%
Senior notes	$ 750,000		750,000
4.75% senior notes, due 2028
Debt Instrument [Line Items]
Long-term debt, interest rate (in percent)	4.75%
Senior notes	$ 750,000		750,000
7% debentures, due 2036
Debt Instrument [Line Items]
Long-term debt, interest rate (in percent)	7.00%
Senior notes	$ 552		552
MGM China first revolving credit facility
Debt Instrument [Line Items]
Long term debt	371,300		1,249,744
MGM China second revolving credit facility
Debt Instrument [Line Items]
Long term debt	0		224,313
LeoVegas senior notes, due 2023
Debt Instrument [Line Items]
Senior notes	$ 0		$ 36,580