Consolidated Variable Interest Entities - Number of FG VIE's Consolidated (Details) - Variable Interest Entity, Primary Beneficiary [Member] - Entity	9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016
Number of FG VIEs Consolidated [Roll Forward]
Number of FG VIE's consolidated, beginning of period	32	34
Number of FG VIE's consolidated	1	1
Number of FG VIE's deconsolidated	(2)	(2)
Number of FG VIE's Matured	0	(1)
Number of FG VIE's consolidated, end of period	31	32