v2.4.0.6

Consolidation of Certain Interests (Narrative) (Details) (USD $) In Millions, unless otherwise specified	0 Months Ended	12 Months Ended							0 Months Ended
	Aug. 06, 2010 Borgata	Dec. 31, 2011 Borgata	Dec. 31, 2010 Borgata	Dec. 31, 2012 Borgata	Dec. 31, 2012 Amended Borgata	Mar. 17, 2010 Maximum Borgata	Dec. 31, 2012 Maximum Amended Borgata	Jan. 31, 2010 Borgata	Mar. 01, 2013 Echelon Development Subsequent Event	Mar. 04, 2013 Echelon Central Energy Facility Subsequent Event LVE
Consolidated Entities [Line Items]
Equity method investment, ownership percentage								50.00%
Proceeds of one-time distribution from subsidiary, including priority distribution	$ 135.4
Proceeds of priority distribution for excess prior capital contributions to parent	30.8		20.8
Sale of joint venture partner interest under regulatory settlement, time period from agreement until sale						30 months	48 months
Sale of joint venture partner interest under regulatory settlement, initial time period under which joint venture partner controls decision to sell					36 months	18 months
Sale of joint venture partner interest under regulatory settlement, increase in time period from agreement until sale					18 months
Sale of joint venture partner interest under regulatory settlement, time period before end of agreement during which divestiture trust controls decision to sell					12 months
Component of fair value of controlling interest, control premium		72.4
Control premium, percentage applied to enterprise value members' equity		10.00%
Noncontrolling interest, ownership percentage by parent				50.00%
Sale of real estate development, consideration received, gross									350
Purchase price of LVE energy center assets										187.0
Sale price of LVE energy center assets										$ 187.0

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