Commitments and Contingencies - Commitments Narrative (Details) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013
Loss Contingencies [Line Items]
Maximum potential funding under commitments	$ 112,000,000	$ 98,000,000
Commitments to fund certain limited partnerships or subsidiaries [Member]
Loss Contingencies [Line Items]
Maximum potential funding under commitments	14,000,000	34,000,000
Commitments funded	$ 20,000,000