Fair Value Measurements, Fair Value Of Financial Instruments as Measured On a Recurring Basis (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2013		Dec. 31, 2012		Dec. 31, 2011	Dec. 31, 2010
Assets [Abstract]
Trading securities	$ 91,616		$ 214,102
Available for sale securities	10,147,162		11,287,221
Fair value option securities	167,125		284,296
Residential mortgage loans held for sale	200,546		293,762
Mortgage servicing rights, net	153,333		100,812		86,783	115,723
Derivative contracts, net of cash margin, Assets, Fair Value	265,012		338,106
Liabilities [Abstract]
Derivative contracts, net of cash margin, Liabilities, Fair Value	247,185		283,589
U.S. Government agency debentures [Member]
Assets [Abstract]
Trading securities	34,120		16,545
U.S. agency residential mortgage-backed securities [Member]
Assets [Abstract]
Trading securities	21,011		86,361
Available for sale securities	7,716,010		9,889,821
Fair value option securities	157,431		257,040
Municipal and other tax-exempt securities [Member]
Assets [Abstract]
Trading securities	27,350		90,326
Available for sale securities	73,775		87,142
Other trading securities [Member]
Assets [Abstract]
Trading securities	9,135		20,870
US Treasury Securities [Member]
Assets [Abstract]
Available for sale securities	1,042		1,002
Privately issued residential mortgage-backed securities [Member]
Assets [Abstract]
Available for sale securities	221,099		325,163
Commercial mortgage-backed securities [Member]
Assets [Abstract]
Available for sale securities	2,055,804		895,075
Other debt securities [Member]
Assets [Abstract]
Available for sale securities	35,241		36,389
Fair value option securities	9,694		770
Perpetual preferred stock [Member]
Assets [Abstract]
Available for sale securities	22,863		25,072
Equity securities and mutual funds [Member]
Assets [Abstract]
Available for sale securities	21,328		27,557
Corporate debt securities [Member]
Assets [Abstract]
Fair value option securities	0		26,486
Fair Value, Measurements, Recurring [Member]
Assets [Abstract]
Trading securities	91,616		214,102
Available for sale securities	10,147,162		11,287,221
Fair value option securities	167,125		284,296
Residential mortgage loans held for sale	200,546		293,762
Mortgage servicing rights, net	153,333	[1]	100,812	[1]
Derivative contracts, net of cash margin, Assets, Fair Value	265,012	[2]	338,106	[3]
Other assets, private equity funds	27,341		28,169
Liabilities [Abstract]
Derivative contracts, net of cash margin, Liabilities, Fair Value	247,185	[2]	283,589	[3]
Fair Value, Measurements, Recurring [Member] | U.S. Government agency debentures [Member]
Assets [Abstract]
Trading securities	34,120		16,545
Fair Value, Measurements, Recurring [Member] | U.S. agency residential mortgage-backed securities [Member]
Assets [Abstract]
Trading securities	21,011		86,361
Available for sale securities	7,716,010		9,889,821
Fair value option securities	157,431		257,040
Fair Value, Measurements, Recurring [Member] | Municipal and other tax-exempt securities [Member]
Assets [Abstract]
Trading securities	27,350		90,326
Available for sale securities	73,775		87,142
Fair Value, Measurements, Recurring [Member] | Other trading securities [Member]
Assets [Abstract]
Trading securities	9,135		20,870
Fair Value, Measurements, Recurring [Member] | US Treasury Securities [Member]
Assets [Abstract]
Available for sale securities	1,042		1,002
Fair Value, Measurements, Recurring [Member] | Privately issued residential mortgage-backed securities [Member]
Assets [Abstract]
Available for sale securities	221,099		325,163
Fair Value, Measurements, Recurring [Member] | Commercial mortgage-backed securities [Member]
Assets [Abstract]
Available for sale securities	2,055,804		895,075
Fair Value, Measurements, Recurring [Member] | Other debt securities [Member]
Assets [Abstract]
Available for sale securities	35,241		36,389
Fair value option securities	9,694		770
Fair Value, Measurements, Recurring [Member] | Perpetual preferred stock [Member]
Assets [Abstract]
Available for sale securities	22,863		25,072
Fair Value, Measurements, Recurring [Member] | Equity securities and mutual funds [Member]
Assets [Abstract]
Available for sale securities	21,328		27,557
Fair Value, Measurements, Recurring [Member] | Corporate debt securities [Member]
Assets [Abstract]
Fair value option securities			26,486
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member]
Assets [Abstract]
Trading securities	0		0
Available for sale securities	1,042		5,167
Fair value option securities	0		0
Residential mortgage loans held for sale			0
Mortgages Held-for-sale, Fair Value Disclosure	0
Mortgage servicing rights, net	0	[1]	0	[1]
Derivative contracts, net of cash margin, Assets, Fair Value	2,712	[2]	11,597	[3]
Other assets, private equity funds	0		0
Liabilities [Abstract]
Derivative contracts, net of cash margin, Liabilities, Fair Value	0	[2]	0	[3]
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member] | U.S. Government agency debentures [Member]
Assets [Abstract]
Trading securities	0		0
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member] | U.S. agency residential mortgage-backed securities [Member]
Assets [Abstract]
Trading securities	0		0
Available for sale securities	0		0
Fair value option securities	0		0
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member] | Municipal and other tax-exempt securities [Member]
Assets [Abstract]
Trading securities	0		0
Available for sale securities	0		0
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member] | Other trading securities [Member]
Assets [Abstract]
Trading securities	0		0
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member] | US Treasury Securities [Member]
Assets [Abstract]
Available for sale securities	1,042		1,002
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member] | Privately issued residential mortgage-backed securities [Member]
Assets [Abstract]
Available for sale securities	0		0
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member] | Commercial mortgage-backed securities [Member]
Assets [Abstract]
Available for sale securities	0		0
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member] | Other debt securities [Member]
Assets [Abstract]
Available for sale securities	0		0
Fair value option securities	0		0
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member] | Perpetual preferred stock [Member]
Assets [Abstract]
Available for sale securities	0		0
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member] | Equity securities and mutual funds [Member]
Assets [Abstract]
Available for sale securities	0		4,165
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member] | Corporate debt securities [Member]
Assets [Abstract]
Fair value option securities			0
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member]
Assets [Abstract]
Trading securities	91,616		214,102
Available for sale securities	10,119,396		11,233,792
Fair value option securities	167,125		284,296
Residential mortgage loans held for sale			293,762
Mortgages Held-for-sale, Fair Value Disclosure	200,546
Mortgage servicing rights, net	0	[1]	0	[1]
Derivative contracts, net of cash margin, Assets, Fair Value	262,300	[2]	326,509	[3]
Other assets, private equity funds	0		0
Liabilities [Abstract]
Derivative contracts, net of cash margin, Liabilities, Fair Value	247,185	[2]	283,589	[3]
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member] | U.S. Government agency debentures [Member]
Assets [Abstract]
Trading securities	34,120		16,545
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member] | U.S. agency residential mortgage-backed securities [Member]
Assets [Abstract]
Trading securities	21,011		86,361
Available for sale securities	7,716,010		9,889,821
Fair value option securities	157,431		257,040
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member] | Municipal and other tax-exempt securities [Member]
Assets [Abstract]
Trading securities	27,350		90,326
Available for sale securities	55,970		46,440
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member] | Other trading securities [Member]
Assets [Abstract]
Trading securities	9,135		20,870
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member] | US Treasury Securities [Member]
Assets [Abstract]
Available for sale securities	0		0
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member] | Privately issued residential mortgage-backed securities [Member]
Assets [Abstract]
Available for sale securities	221,099		325,163
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member] | Commercial mortgage-backed securities [Member]
Assets [Abstract]
Available for sale securities	2,055,804		895,075
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member] | Other debt securities [Member]
Assets [Abstract]
Available for sale securities	30,529		30,990
Fair value option securities	9,694		770
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member] | Perpetual preferred stock [Member]
Assets [Abstract]
Available for sale securities	22,863		25,072
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member] | Equity securities and mutual funds [Member]
Assets [Abstract]
Available for sale securities	17,121		21,231
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member] | Corporate debt securities [Member]
Assets [Abstract]
Fair value option securities			26,486
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 3 [Member]
Assets [Abstract]
Trading securities	0		0
Available for sale securities	26,724		48,262
Fair value option securities	0		0
Residential mortgage loans held for sale			0
Mortgages Held-for-sale, Fair Value Disclosure	0
Mortgage servicing rights, net	153,333	[1]	100,812	[1]
Derivative contracts, net of cash margin, Assets, Fair Value	0	[2]	0	[3]
Other assets, private equity funds	27,341		28,169
Liabilities [Abstract]
Derivative contracts, net of cash margin, Liabilities, Fair Value	0	[2]	0	[3]
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 3 [Member] | U.S. Government agency debentures [Member]
Assets [Abstract]
Trading securities	0		0
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 3 [Member] | U.S. agency residential mortgage-backed securities [Member]
Assets [Abstract]
Trading securities	0		0
Available for sale securities	0		0
Fair value option securities	0		0
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 3 [Member] | Municipal and other tax-exempt securities [Member]
Assets [Abstract]
Trading securities	0		0
Available for sale securities	17,805		40,702
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 3 [Member] | Other trading securities [Member]
Assets [Abstract]
Trading securities	0		0
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 3 [Member] | US Treasury Securities [Member]
Assets [Abstract]
Available for sale securities	0		0
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 3 [Member] | Privately issued residential mortgage-backed securities [Member]
Assets [Abstract]
Available for sale securities	0		0
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 3 [Member] | Commercial mortgage-backed securities [Member]
Assets [Abstract]
Available for sale securities	0		0
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 3 [Member] | Other debt securities [Member]
Assets [Abstract]
Available for sale securities	4,712		5,399
Fair value option securities	0		0
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 3 [Member] | Perpetual preferred stock [Member]
Assets [Abstract]
Available for sale securities	0		0
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 3 [Member] | Corporate debt securities [Member]
Assets [Abstract]
Fair value option securities			$ 0

[1] A reconciliation of the beginning and ending fair value of mortgage servicing rights and disclosures of significant assumptions used to determine fair value are presented in Note 7, Mortgage Banking Activities.

[2] See Note 3 for detail of fair value of derivative contracts by contract type. Derivative contracts based on quoted prices in active markets or identical instruments (Level 1) are exchange-traded energy derivative contracts, net of cash margin.

[3] See Note 3 for detail of fair value of derivative contracts by contract type. Derivative contracts based on quoted prices in active markets for identical instruments (Level 1) are exchange-traded energy and agricultural derivative contracts, net of cash margin.