Commitments, Contingencies And Guarantees (External Credit Ratings Of Underlying Or Referenced Assets For Credit Related Derivatives Contracts) (Details) (USD $) In Millions, unless otherwise specified	Jun. 30, 2014
Commitments And Guarantee Obligations [Line Items]
Maximum Payout	$ 3,252.0
AAA/Aaa [Member] | Index credit default swaps [Member]
Commitments And Guarantee Obligations [Line Items]
Maximum Payout	344.8
BBB/Baa [Member] | Single name credit default swaps [Member]
Commitments And Guarantee Obligations [Line Items]
Maximum Payout	61.0
Below Investment Grade [Member] | Single name credit default swaps [Member]
Commitments And Guarantee Obligations [Line Items]
Maximum Payout	15.0
Notional/Maximum Payout [Member] | Index credit default swaps [Member]
Commitments And Guarantee Obligations [Line Items]
Maximum Payout	344.8
Notional/Maximum Payout [Member] | Single name credit default swaps [Member]
Commitments And Guarantee Obligations [Line Items]
Maximum Payout	$ 76.0