Operating Units Investment Segment (Details) (USD $)	3 Months Ended	0 Months Ended
	Mar. 31, 2011	Jul. 02, 2012 Investment Funds [Member]	Dec. 31, 2012 Investment Funds [Member]	Dec. 31, 2011 Investment Funds [Member]
Segment Reporting Information [Line Items]
Special Profits Interest Allocation	$ 9,000,000
Incentive Allocation	7,000,000
Investment in funds		300,000,000
Fair value of our intrest in Funds of subsidiary			$ 2,400,000,000	$ 3,100,000,000