Consolidation Financial Support for Nonconsolidated Legal Entity (Details) $ in Millions	12 Months Ended
Dec. 31, 2016 USD ($)
Financial Support, Waived Fees [Member]
Financial Support for Nonconsolidated Legal Entity [Line Items]
Nonconsolidated Legal Entity, Financial Support Amount	$ 309.6
Financial Support, Capital Contributions [Member]
Financial Support for Nonconsolidated Legal Entity [Line Items]
Nonconsolidated Legal Entity, Financial Support Amount	$ 0.0

Amount of financial support provided to a nonconsolidated legal entity that is required to comply with or operate in accordance with requirements that are similar to those included in Rule 2a-7 of the Investment Company Act of 1940 for registered money market funds.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 810
-SubTopic 10
-Section 15
-Paragraph 12
-Subparagraph (f)(2)
-URI http://asc.fasb.org/extlink&oid=66022390&loc=d3e923-111674

Name:	us-gaap_NonconsolidatedLegalEntityFinancialSupportAmount
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration