Commitments and Contingencies (Borgata Leases) (Details) (Borgata)	12 Months Ended
	Dec. 31, 2012 acre
Operating Leased Assets [Line Items]
Owned land, acres	26
Land subject to ground leases	20
Land Underlying Parking Garage
Operating Leased Assets [Line Items]
Land subject to ground leases	2
Land Underlying Public Space Expansion
Operating Leased Assets [Line Items]
Land subject to ground leases	4
Land Underlying Rooms Expansion
Operating Leased Assets [Line Items]
Land subject to ground leases	2
Land Underlying Parking Structure
Operating Leased Assets [Line Items]
Land subject to ground leases	3
Land Comprising Surface Parking Lot
Operating Leased Assets [Line Items]
Land subject to ground leases	8
Termination of lease, period of time after notice given	6 months
Undeveloped Land Parcel
Operating Leased Assets [Line Items]
Land subject to ground leases	1
Alternative Parking Structure Ground Lease
Operating Leased Assets [Line Items]
Responsibility for property taxes and monthly rent, term	18 months