Commitments, Contingencies And Guarantees (Guarantees) (Details) $ in Millions	Mar. 31, 2016 USD ($)
Guarantee Obligations [Line Items]
Maximum Payout	$ 3,656.2
Derivative Contracts - Non-Credit Related [Member] | Derivative Notional Amount [Member]
Guarantee Obligations [Line Items]
2016	13,418.6
2017	1,048.6
2018 and 2019	348.1
2020 and 2021	0.0
2022 and Later	426.7
Maximum Payout	15,242.0
Written Derivative Contracts - Credit Related [Member] | Derivative Notional Amount [Member]
Guarantee Obligations [Line Items]
2016	0.0
2017	0.0
2018 and 2019	90.2
2020 and 2021	197.0
2022 and Later	2.5
Maximum Payout	289.7
Derivative [Member] | Derivative Notional Amount [Member]
Guarantee Obligations [Line Items]
2016	13,418.6
2017	1,048.6
2018 and 2019	438.3
2020 and 2021	197.0
2022 and Later	429.2
Maximum Payout	$ 15,531.7