Long-Term Debt - Schedule of Long-Term Debt (Parenthetical) (Detail) - USD ($) $ in Millions	1 Months Ended					12 Months Ended
	Dec. 31, 2019	May 31, 2019	Apr. 30, 2019	Feb. 28, 2019	Jun. 30, 2018	Dec. 31, 2019	Dec. 31, 2018
8.625% Senior Notes, Due 2019 [Member]
Debt Instrument [Line Items]
Long-term debt, principal amount							$ 850.0
Long-term debt, interest rate (as a percent)				8.625%			8.625%
Long-term debt, maturity year				2019			2019
5.25% Senior Notes, Due 2020 [Member]
Debt Instrument [Line Items]
Long-term debt, principal amount							$ 500.0
Long-term debt, interest rate (as a percent)	5.25%		5.25%			5.25%	5.25%
Long-term debt, maturity year	2020		2020				2020
6.75% Senior Notes, Due 2020 [Member]
Debt Instrument [Line Items]
Long-term debt, principal amount							$ 1,000.0
Long-term debt, interest rate (as a percent)	6.75%		6.75%			6.75%	6.75%
Long-term debt, maturity year	2020		2020				2020
6.625% Senior Notes, Due 2021 [Member]
Debt Instrument [Line Items]
Long-term debt, principal amount							$ 1,250.0
Long-term debt, interest rate (as a percent)	6.625%					6.625%	6.625%
Long-term debt, maturity year	2021						2021
7.75% Senior Notes, Due 2022 [Member]
Debt Instrument [Line Items]
Long-term debt, principal amount	$ 1,000.0					$ 1,000.0	$ 1,000.0
Long-term debt, interest rate (as a percent)	7.75%					7.75%	7.75%
Long-term debt, maturity year						2022	2022
6% Senior Notes, Due 2023 [Member]
Debt Instrument [Line Items]
Long-term debt, principal amount	$ 1,250.0					$ 1,250.0	$ 1,250.0
Long-term debt, interest rate (as a percent)	6.00%					6.00%	6.00%
Long-term debt, maturity year						2023	2023
5.625% Operating Partnership Senior Notes, Due 2024 [Member]
Debt Instrument [Line Items]
Long-term debt, principal amount	$ 1,050.0					$ 1,050.0	$ 1,050.0
Long-term debt, interest rate (as a percent)	5.625%					5.625%	5.625%
Long-term debt, maturity year						2024	2024
5.375% MGM China Senior Notes, Due 2024 [Member]
Debt Instrument [Line Items]
Long-term debt, principal amount	$ 750.0	$ 750.0				$ 750.0
Long-term debt, interest rate (as a percent)	5.375%	5.375%				5.375%
Long-term debt, maturity year		2024				2024
5.75% Senior Notes, Due 2025 [Member]
Debt Instrument [Line Items]
Long-term debt, principal amount	$ 1,000.0				$ 1,000.0	$ 1,000.0	$ 1,000.0
Long-term debt, interest rate (as a percent)	5.75%				5.75%	5.75%	5.75%
Long-term debt, maturity year					2025	2025	2025
5.875% MGM China Senior Notes, Due 2026 [Member]
Debt Instrument [Line Items]
Long-term debt, principal amount	$ 750.0	$ 750.0				$ 750.0
Long-term debt, interest rate (as a percent)	5.875%	5.875%				5.875%
Long-term debt, maturity year		2026				2026
4.50% Operating Partnership Senior Notes, Due 2026 [Member]
Debt Instrument [Line Items]
Long-term debt, principal amount	$ 500.0					$ 500.0	$ 500.0
Long-term debt, interest rate (as a percent)	4.50%					4.50%	4.50%
Long-term debt, maturity year						2026	2026
4.625% Senior Notes, Due 2026 [Member]
Debt Instrument [Line Items]
Long-term debt, principal amount	$ 500.0					$ 500.0	$ 500.0
Long-term debt, interest rate (as a percent)	4.625%					4.625%	4.625%
Long-term debt, maturity year						2026	2026
5.75% Operating Partnership Senior Notes, Due 2027 [Member]
Debt Instrument [Line Items]
Long-term debt, principal amount	$ 750.0					$ 750.0
Long-term debt, interest rate (as a percent)	5.75%					5.75%
Long-term debt, maturity year						2027
5.5% Senior Notes, Due 2027 [Member]
Debt Instrument [Line Items]
Long-term debt, principal amount	$ 1,000.0		$ 1,000.0			$ 1,000.0
Long-term debt, interest rate (as a percent)	5.50%		5.50%			5.50%
Long-term debt, maturity year			2027			2027
4.50% Operating Partnership Senior Notes, Due 2028 [Member]
Debt Instrument [Line Items]
Long-term debt, principal amount	$ 350.0					$ 350.0	$ 350.0
Long-term debt, interest rate (as a percent)	4.50%					4.50%	4.50%
Long-term debt, maturity year						2028	2028
7% Debentures, Due 2036 [Member]
Debt Instrument [Line Items]
Long-term debt, principal amount	$ 0.6					$ 0.6	$ 0.6
Long-term debt, interest rate (as a percent)	7.00%					7.00%	7.00%
Long-term debt, maturity year						2036	2036