Equity-Based Compensation (Details) (USD $) In Millions, except Per Share data, unless otherwise specified	12 Months Ended						12 Months Ended
	Dec. 31, 2012 Partnership Restricted Equity Units (Class A-2) [Member]	Dec. 31, 2011 Partnership Restricted Equity Units (Class A-2) [Member]	Dec. 31, 2010 Partnership Restricted Equity Units (Class A-2) [Member]	Dec. 31, 2012 Worldwide [Member]	Dec. 31, 2011 Worldwide [Member]	Dec. 31, 2009 Worldwide [Member]	Dec. 31, 2012 Worldwide [Member] Restricted Share Units [Member]	Dec. 31, 2011 Worldwide [Member] Restricted Share Units [Member]	Dec. 31, 2009 Worldwide [Member] Restricted Share Units [Member]
Summary of company's equity award programs
Beginning Balance, Number of Shares	93.0	99.5	90.0	1.9			0.8
Granted at fair market value, Number of Shares	11.2	1.7	11.0		2.6			0.8
Vesting of restricted share units, Number of Shares				0.2			(0.2)
Net shares settlement, Number of Shares	(1.9)	(2.2)		(0.5)	(0.7)
Forfeited, Number of Shares	(0.1)	(6.0)	(1.5)				(0.1)
Ending Balance, Number of Shares	102.2	93.0	99.5	1.6	1.9		0.5	0.8
Beginning Balance, Weighted Average Grant Date Fair Value	$ 2.27	$ 2.20	$ 2.32	$ 1.85			$ 1.85
Granted at fair market value, Weighted Average Grant Date Fair Value	$ 0.11	$ 0.47	$ 1.12		$ 1.85			$ 1.85
Vesting of restricted share units, Weighted Average Grant Date Fair Value				$ 1.85			$ 1.85
Net share settlement, Weighted Average Grant Date Fair Value	$ 0.11	$ 0.88		$ 1.85	$ 1.85
Forfeited, Weighted Average Grant Date Fair Value	$ 0.11	$ 1.12	$ 1.26				$ 1.85
Ending Balance, Weighted Average Grant Date Fair Value	$ 2.08	$ 2.27	$ 2.20	$ 1.85	$ 1.85		$ 1.85	$ 1.85