Fair Values of Assets and Liabilities (Details) (USD $) In Thousands	Sep. 30, 2011	Dec. 31, 2010	Sep. 30, 2010
Assets measured at fair value on a recurring basis
Mortgage loans held for sale	$ 331,883	$ 754,117	$ 699,001
Recurring Basis [Member]
Assets measured at fair value on a recurring basis
Mortgage loans held for sale	331,883	754,117	699,001
Trading account securities	85,711	185,404	138,677
Available-for-sale and other securities	8,403,250	9,586,522	9,413,416
Automobile loans	344,529	522,717	590,223
MSR's	73,824	125,679	112,155
Derivative assets	452,693	346,133	434,288
Liabilities measured at fair value on a recurring basis
Securitization trust notes payable	173,045	356,089	422,294
Derivative liabilities	295,872	239,240	306,803
Other liabilities	2,010	0	0
Recurring Basis [Member] | Level 1 [Member]
Assets measured at fair value on a recurring basis
Mortgage loans held for sale	0	0	0
Trading account securities	54,753	116,447	63,105
Available-for-sale and other securities	107,557	105,067	2,687,196
Automobile loans	0	0	401,148
MSR's	0	0	0
Derivative assets	20,581	23,514	980
Liabilities measured at fair value on a recurring basis
Securitization trust notes payable	0	0	422,294
Derivative liabilities	29,820	3,990	9,044
Other liabilities	2,010	0	0
Recurring Basis [Member] | Level 1 [Member] | U.S. Treasury [Member]
Assets measured at fair value on a recurring basis
Trading account securities		47,430	0
Available-for-sale and other securities	53,321	51,781	50,334
Recurring Basis [Member] | Level 1 [Member] | Federal agencies - mortgage backed securities [Member]
Assets measured at fair value on a recurring basis
Trading account securities		0	0
Available-for-sale and other securities	0	0	0
Recurring Basis [Member] | Level 1 [Member] | TLGP securities [Member]
Assets measured at fair value on a recurring basis
Available-for-sale and other securities	0	0	580,914
Recurring Basis [Member] | Level 1 [Member] | Federal agencies: Other agencies [Member]
Assets measured at fair value on a recurring basis
Trading account securities		0	0
Available-for-sale and other securities	0	0	2,001,730
Recurring Basis [Member] | Level 1 [Member] | Municipal securities [Member]
Assets measured at fair value on a recurring basis
Trading account securities		0	0
Available-for-sale and other securities	0	0	0
Recurring Basis [Member] | Level 1 [Member] | Private label CMO [Member]
Assets measured at fair value on a recurring basis
Available-for-sale and other securities	0	0	0
Recurring Basis [Member] | Level 1 [Member] | Asset-backed Securities [Member]
Assets measured at fair value on a recurring basis
Available-for-sale and other securities	0	0	0
Recurring Basis [Member] | Level 1 [Member] | Covered Bonds [Member]
Assets measured at fair value on a recurring basis
Available-for-sale and other securities	0	0	0
Recurring Basis [Member] | Level 1 [Member] | Corporate debt [Member]
Assets measured at fair value on a recurring basis
Available-for-sale and other securities	0	0	0
Recurring Basis [Member] | Level 1 [Member] | Other securities [Member]
Assets measured at fair value on a recurring basis
Trading account securities		69,017	63,105
Available-for-sale and other securities	54,236	53,286	54,218
Recurring Basis [Member] | Level 2 [Member]
Assets measured at fair value on a recurring basis
Mortgage loans held for sale	331,883	754,117	699,001
Trading account securities	30,958	68,957	75,572
Available-for-sale and other securities	7,962,347	9,047,040	6,018,748
Automobile loans	0	0	0
MSR's	0	0	0
Derivative assets	526,890	390,361	547,784
Liabilities measured at fair value on a recurring basis
Securitization trust notes payable	173,045	356,089	0
Derivative liabilities	265,023	233,399	293,741
Other liabilities	0	0	0
Recurring Basis [Member] | Level 2 [Member] | U.S. Treasury [Member]
Assets measured at fair value on a recurring basis
Trading account securities	0	0	0
Available-for-sale and other securities	0	0	0
Recurring Basis [Member] | Level 2 [Member] | Federal agencies - mortgage backed securities [Member]
Assets measured at fair value on a recurring basis
Trading account securities	6,995	10,860	12,731
Available-for-sale and other securities	4,435,246	4,754,404	4,683,540
Recurring Basis [Member] | Level 2 [Member] | TLGP securities [Member]
Assets measured at fair value on a recurring basis
Available-for-sale and other securities	105,537	183,467	0
Recurring Basis [Member] | Level 2 [Member] | Federal agencies: Other agencies [Member]
Assets measured at fair value on a recurring basis
Trading account securities	0	24,853	24,990
Available-for-sale and other securities	1,137,954	2,058,376	30,445
Recurring Basis [Member] | Level 2 [Member] | Municipal securities [Member]
Assets measured at fair value on a recurring basis
Trading account securities	23,455	30,205	33,554
Available-for-sale and other securities	311,962	305,909	134,582
Recurring Basis [Member] | Level 2 [Member] | Private label CMO [Member]
Assets measured at fair value on a recurring basis
Available-for-sale and other securities	0	0	0
Recurring Basis [Member] | Level 2 [Member] | Asset-backed Securities [Member]
Assets measured at fair value on a recurring basis
Available-for-sale and other securities	803,039	1,044,438	979,666
Recurring Basis [Member] | Level 2 [Member] | Covered Bonds [Member]
Assets measured at fair value on a recurring basis
Available-for-sale and other securities	703,630	367,209	151,310
Recurring Basis [Member] | Level 2 [Member] | Corporate debt [Member]
Assets measured at fair value on a recurring basis
Available-for-sale and other securities	454,852	323,389	30,154
Recurring Basis [Member] | Level 2 [Member] | Other securities [Member]
Assets measured at fair value on a recurring basis
Trading account securities	508	3,039	4,297
Available-for-sale and other securities	10,127	9,848	9,051
Recurring Basis [Member] | Level 3 [Member]
Assets measured at fair value on a recurring basis
Mortgage loans held for sale	0	0	0
Trading account securities	0	0	0
Available-for-sale and other securities	333,346	434,415	707,472
Automobile loans	344,529	522,717	189,075
MSR's	73,824	125,679	112,155
Derivative assets	8,963	2,817	11,745
Liabilities measured at fair value on a recurring basis
Securitization trust notes payable	0	0	0
Derivative liabilities	1,029	1,851	4,018
Other liabilities	0	0	0
Recurring Basis [Member] | Level 3 [Member] | U.S. Treasury [Member]
Assets measured at fair value on a recurring basis
Trading account securities		0	0
Available-for-sale and other securities	0	0	0
Recurring Basis [Member] | Level 3 [Member] | Federal agencies - mortgage backed securities [Member]
Assets measured at fair value on a recurring basis
Trading account securities		0	0
Available-for-sale and other securities	0	0	0
Recurring Basis [Member] | Level 3 [Member] | TLGP securities [Member]
Assets measured at fair value on a recurring basis
Available-for-sale and other securities	0	0	0
Recurring Basis [Member] | Level 3 [Member] | Federal agencies: Other agencies [Member]
Assets measured at fair value on a recurring basis
Trading account securities		0
Available-for-sale and other securities	0	0	0
Recurring Basis [Member] | Level 3 [Member] | Municipal securities [Member]
Assets measured at fair value on a recurring basis
Trading account securities		0
Available-for-sale and other securities	101,427	149,806	233,290
Recurring Basis [Member] | Level 3 [Member] | Private label CMO [Member]
Assets measured at fair value on a recurring basis
Available-for-sale and other securities	78,900	121,925	276,224
Recurring Basis [Member] | Level 3 [Member] | Asset-backed Securities [Member]
Assets measured at fair value on a recurring basis
Available-for-sale and other securities	153,019	162,684	197,958
Recurring Basis [Member] | Level 3 [Member] | Covered Bonds [Member]
Assets measured at fair value on a recurring basis
Available-for-sale and other securities	0	0	0
Recurring Basis [Member] | Level 3 [Member] | Corporate debt [Member]
Assets measured at fair value on a recurring basis
Available-for-sale and other securities	0	0	0
Recurring Basis [Member] | Level 3 [Member] | Other securities [Member]
Assets measured at fair value on a recurring basis
Trading account securities		0	0
Available-for-sale and other securities	0	0	0
Recurring Basis [Member] | Netting Adjustments [Member]
Assets measured at fair value on a recurring basis
Mortgage loans held for sale	0	0	0
Trading account securities	0	0	0
Available-for-sale and other securities	0	0	0
Automobile loans	0	0	0
MSR's	0	0	0
Derivative assets	(103,741)	(70,559)	(126,221)
Liabilities measured at fair value on a recurring basis
Securitization trust notes payable	0	0	0
Derivative liabilities	0	0	0
Other liabilities	0	0	0
Recurring Basis [Member] | Netting Adjustments [Member] | U.S. Treasury [Member]
Assets measured at fair value on a recurring basis
Trading account securities	0	0	0
Available-for-sale and other securities	0	0
Recurring Basis [Member] | Netting Adjustments [Member] | Federal agencies - mortgage backed securities [Member]
Assets measured at fair value on a recurring basis
Trading account securities	0	0
Available-for-sale and other securities	0	0	0
Recurring Basis [Member] | Netting Adjustments [Member] | TLGP securities [Member]
Assets measured at fair value on a recurring basis
Available-for-sale and other securities	0	0	0
Recurring Basis [Member] | Netting Adjustments [Member] | Federal agencies: Other agencies [Member]
Assets measured at fair value on a recurring basis
Trading account securities	0	0	0
Available-for-sale and other securities	0	0	0
Recurring Basis [Member] | Netting Adjustments [Member] | Municipal securities [Member]
Assets measured at fair value on a recurring basis
Trading account securities	0	0	0
Available-for-sale and other securities	0	0	0
Recurring Basis [Member] | Netting Adjustments [Member] | Private label CMO [Member]
Assets measured at fair value on a recurring basis
Available-for-sale and other securities	0	0	0
Recurring Basis [Member] | Netting Adjustments [Member] | Asset-backed Securities [Member]
Assets measured at fair value on a recurring basis
Available-for-sale and other securities	0	0	0
Recurring Basis [Member] | Netting Adjustments [Member] | Covered Bonds [Member]
Assets measured at fair value on a recurring basis
Available-for-sale and other securities	0	0	0
Recurring Basis [Member] | Netting Adjustments [Member] | Corporate debt [Member]
Assets measured at fair value on a recurring basis
Available-for-sale and other securities	0	0	0
Recurring Basis [Member] | Netting Adjustments [Member] | Other securities [Member]
Assets measured at fair value on a recurring basis
Trading account securities	0	0	0
Available-for-sale and other securities	0	0	0
Recurring Basis [Member] | U.S. Treasury [Member]
Assets measured at fair value on a recurring basis
Trading account securities	0	47,430	0
Available-for-sale and other securities		51,781	50,334
Recurring Basis [Member] | Federal agencies - mortgage backed securities [Member]
Assets measured at fair value on a recurring basis
Trading account securities	6,995	10,860	12,731
Available-for-sale and other securities		4,754,404	4,683,540
Recurring Basis [Member] | TLGP securities [Member]
Assets measured at fair value on a recurring basis
Available-for-sale and other securities		183,467	580,914
Recurring Basis [Member] | Federal agencies: Other agencies [Member]
Assets measured at fair value on a recurring basis
Trading account securities	0	24,853	24,990
Available-for-sale and other securities		2,058,376	2,032,175
Recurring Basis [Member] | Municipal securities [Member]
Assets measured at fair value on a recurring basis
Trading account securities	23,455	30,205	33,554
Available-for-sale and other securities		455,715	367,872
Recurring Basis [Member] | Private label CMO [Member]
Assets measured at fair value on a recurring basis
Available-for-sale and other securities		121,925	276,224
Recurring Basis [Member] | Asset-backed Securities [Member]
Assets measured at fair value on a recurring basis
Available-for-sale and other securities		1,207,122	1,177,624
Recurring Basis [Member] | Covered Bonds [Member]
Assets measured at fair value on a recurring basis
Available-for-sale and other securities		367,209	151,310
Recurring Basis [Member] | Corporate debt [Member]
Assets measured at fair value on a recurring basis
Available-for-sale and other securities		323,389	30,154
Recurring Basis [Member] | Other securities [Member]
Assets measured at fair value on a recurring basis
Trading account securities	55,261	72,056	67,402
Available-for-sale and other securities		63,134	63,269
Level 1 [Member] | U.S. Treasury [Member]
Assets measured at fair value on a recurring basis
Trading account securities	0
Level 1 [Member] | Federal agencies - mortgage backed securities [Member]
Assets measured at fair value on a recurring basis
Trading account securities	0
Level 1 [Member] | Federal agencies: Other agencies [Member]
Assets measured at fair value on a recurring basis
Trading account securities	0
Level 1 [Member] | Municipal securities [Member]
Assets measured at fair value on a recurring basis
Trading account securities	0
Level 1 [Member] | Other securities [Member]
Assets measured at fair value on a recurring basis
Trading account securities	54,753
Level 3 [Member] | U.S. Treasury [Member]
Assets measured at fair value on a recurring basis
Trading account securities	0
Level 3 [Member] | Federal agencies - mortgage backed securities [Member]
Assets measured at fair value on a recurring basis
Trading account securities	0
Level 3 [Member] | Federal agencies: Other agencies [Member]
Assets measured at fair value on a recurring basis
Trading account securities	0
Level 3 [Member] | Municipal securities [Member]
Assets measured at fair value on a recurring basis
Trading account securities	0
Level 3 [Member] | Other securities [Member]
Assets measured at fair value on a recurring basis
Trading account securities	0
U.S. Treasury [Member]
Assets measured at fair value on a recurring basis
Available-for-sale and other securities	53,321
Federal agencies - mortgage backed securities [Member]
Assets measured at fair value on a recurring basis
Available-for-sale and other securities	4,435,246
TLGP securities [Member]
Assets measured at fair value on a recurring basis
Available-for-sale and other securities	105,537
Federal agencies: Other agencies [Member]
Assets measured at fair value on a recurring basis
Available-for-sale and other securities	1,137,954
Municipal securities [Member]
Assets measured at fair value on a recurring basis
Available-for-sale and other securities	413,389
Private label CMO [Member]
Assets measured at fair value on a recurring basis
Available-for-sale and other securities	78,900
Asset-backed Securities [Member]
Assets measured at fair value on a recurring basis
Available-for-sale and other securities	956,058
Covered Bonds [Member]
Assets measured at fair value on a recurring basis
Available-for-sale and other securities	703,630
Corporate debt [Member]
Assets measured at fair value on a recurring basis
Available-for-sale and other securities	454,852
Other securities [Member]
Assets measured at fair value on a recurring basis
Available-for-sale and other securities	$ 64,363