Contingencies - Legal and Regulatory Matters Narrative (Details) £ in Millions, $ in Millions		1 Months Ended
	Aug. 31, 2009 USD ($) cases	Jan. 31, 2014 USD ($) claim	Jan. 31, 2014 GBP (£) claim	Oct. 31, 2009 USD ($)	Jun. 30, 2015 USD ($) claim
Loss Contingencies [Line Items]
Number of lawsuits from related participants of agency securities lending program | cases	2
Securities Finance
Loss Contingencies [Line Items]
Loss contingency, damages sought, value	$ 125.0
Litigation reserve					$ 11.0
Realized loss on sales of securities					10.0
Foreign Exchange
Loss Contingencies [Line Items]
Actual damages asserted by attorney general				$ 100.0
Loss Contingency, Estimate of Possible Loss					$ 585.0
Putative Class Action
Loss Contingencies [Line Items]
Number of pending claims | claim					2
Transition Management
Loss Contingencies [Line Items]
Litigation reserve					$ 2.6
Claims settled | claim		6	6
Transition Management | Legal Reserve
Loss Contingencies [Line Items]
Legal reserves					$ 611.0
Transition Management | Regulatory Matter
Loss Contingencies [Line Items]
Settlement, amount		$ 37.8	£ 22.9