Derivative Financial Instruments (Remaining Contract Maturity Of Fair Value Of OTC Derivative Assets And Liabilities) (Details) $ in Thousands	Mar. 31, 2017 USD ($)
Remaining Contract Maturity Of Fair Value Of Over Counter Derivative Assets And Liabilities [Line Items]
OTC derivative assets having maturity period of 0 to 12 months	$ 95,612
OTC derivative assets having maturity period of 1 to 5 years	209,337
OTC derivative assets having maturity period of greater than 5 years	131,322
OTC derivative assets cross-maturity netting	(79,776)
Total OTC derivative assets, net of cross-maturity netting	356,495
Cross product counterparty netting	(1,512)
Total OTC derivative assets included in Trading assets	354,983
OTC derivative liabilities having maturity period of 0 to 12 months	94,648
OTC derivative liabilities having maturity period of 1 to 5 years	152,292
OTC derivative liabilities having maturity period of greater than 5 years	98,952
OTC derivative liabilities cross-maturity netting	(79,776)
Total OTC derivative liabilities, net of cross-maturity netting	266,116
Cross product counterparty netting	(1,512)
Total OTC derivative liabilities included in Trading liabilities	264,604
Exchange traded derivative assets and other credit agreements	15,500
Cash collateral received	176,500
Exchange traded derivative liabilities and other credit agreements	254,900
Cash collateral pledged	144,200
Commodity Swaps, Options And Forwards [Member]
Remaining Contract Maturity Of Fair Value Of Over Counter Derivative Assets And Liabilities [Line Items]
OTC derivative assets having maturity period of 0 to 12 months	371
OTC derivative assets having maturity period of 1 to 5 years	62
OTC derivative assets having maturity period of greater than 5 years	0
OTC derivative assets cross-maturity netting	0
Total OTC derivative assets, net of cross-maturity netting	433
OTC derivative liabilities having maturity period of 0 to 12 months	1,582
OTC derivative liabilities having maturity period of 1 to 5 years	0
OTC derivative liabilities having maturity period of greater than 5 years	0
OTC derivative liabilities cross-maturity netting	0
Total OTC derivative liabilities, net of cross-maturity netting	1,582
Equity Swaps And Options [Member]
Remaining Contract Maturity Of Fair Value Of Over Counter Derivative Assets And Liabilities [Line Items]
OTC derivative assets having maturity period of 0 to 12 months	19,143
OTC derivative assets having maturity period of 1 to 5 years	3,271
OTC derivative assets having maturity period of greater than 5 years	0
OTC derivative assets cross-maturity netting	0
Total OTC derivative assets, net of cross-maturity netting	22,414
OTC derivative liabilities having maturity period of 0 to 12 months	13,148
OTC derivative liabilities having maturity period of 1 to 5 years	17,187
OTC derivative liabilities having maturity period of greater than 5 years	1,994
OTC derivative liabilities cross-maturity netting	0
Total OTC derivative liabilities, net of cross-maturity netting	32,329
Credit Default Swap [Member]
Remaining Contract Maturity Of Fair Value Of Over Counter Derivative Assets And Liabilities [Line Items]
OTC derivative assets having maturity period of 0 to 12 months	0
OTC derivative assets having maturity period of 1 to 5 years	14,487
OTC derivative assets having maturity period of greater than 5 years	6,449
OTC derivative assets cross-maturity netting	0
Total OTC derivative assets, net of cross-maturity netting	20,936
OTC derivative liabilities having maturity period of 0 to 12 months	178
OTC derivative liabilities having maturity period of 1 to 5 years	13,155
OTC derivative liabilities having maturity period of greater than 5 years	0
OTC derivative liabilities cross-maturity netting	0
Total OTC derivative liabilities, net of cross-maturity netting	13,333
Total Return Swap [Member]
Remaining Contract Maturity Of Fair Value Of Over Counter Derivative Assets And Liabilities [Line Items]
OTC derivative assets having maturity period of 0 to 12 months	6,384
OTC derivative assets having maturity period of 1 to 5 years	771
OTC derivative assets having maturity period of greater than 5 years	0
OTC derivative assets cross-maturity netting	(38)
Total OTC derivative assets, net of cross-maturity netting	7,117
OTC derivative liabilities having maturity period of 0 to 12 months	20,221
OTC derivative liabilities having maturity period of 1 to 5 years	2,391
OTC derivative liabilities having maturity period of greater than 5 years	0
OTC derivative liabilities cross-maturity netting	(38)
Total OTC derivative liabilities, net of cross-maturity netting	22,574
Foreign Currency Forwards, Swaps And Options [Member]
Remaining Contract Maturity Of Fair Value Of Over Counter Derivative Assets And Liabilities [Line Items]
OTC derivative assets having maturity period of 0 to 12 months	37,502
OTC derivative assets having maturity period of 1 to 5 years	37,500
OTC derivative assets having maturity period of greater than 5 years	0
OTC derivative assets cross-maturity netting	(13,111)
Total OTC derivative assets, net of cross-maturity netting	61,891
OTC derivative liabilities having maturity period of 0 to 12 months	39,898
OTC derivative liabilities having maturity period of 1 to 5 years	27,382
OTC derivative liabilities having maturity period of greater than 5 years	0
OTC derivative liabilities cross-maturity netting	(13,111)
Total OTC derivative liabilities, net of cross-maturity netting	54,169
Fixed Income Forwards [Member]
Remaining Contract Maturity Of Fair Value Of Over Counter Derivative Assets And Liabilities [Line Items]
OTC derivative liabilities having maturity period of 0 to 12 months	275
OTC derivative liabilities having maturity period of 1 to 5 years	0
OTC derivative liabilities having maturity period of greater than 5 years	0
OTC derivative liabilities cross-maturity netting	0
Total OTC derivative liabilities, net of cross-maturity netting	275
Interest Rate Swap [Member]
Remaining Contract Maturity Of Fair Value Of Over Counter Derivative Assets And Liabilities [Line Items]
OTC derivative assets having maturity period of 0 to 12 months	32,212
OTC derivative assets having maturity period of 1 to 5 years	153,246
OTC derivative assets having maturity period of greater than 5 years	124,873
OTC derivative assets cross-maturity netting	(66,627)
Total OTC derivative assets, net of cross-maturity netting	243,704
OTC derivative liabilities having maturity period of 0 to 12 months	19,346
OTC derivative liabilities having maturity period of 1 to 5 years	92,177
OTC derivative liabilities having maturity period of greater than 5 years	96,958
OTC derivative liabilities cross-maturity netting	(66,627)
Total OTC derivative liabilities, net of cross-maturity netting	$ 141,854