Loans and leases and the allowance for credit losses (Details 1) (USD $) In Thousands	Sep. 30, 2011	Dec. 31, 2010
Summary of current, past due and nonaccrual loans
Current	$ 55,201,535	$ 49,739,383
30-89 days past due	854,584	645,193
90 days or more past due and accruing	309,966	269,593
Purchased impaired	703,632	97,019
Other acquired impaired	217,759	99,454
Nonaccrual	1,113,788	1,139,740
Loans and leases, net of unearned discount	58,401,264	51,990,382
Commercial, financial, leasing, etc. [Member]
Summary of current, past due and nonaccrual loans
Current	14,943,399	13,088,887
30-89 days past due	45,226	96,087
90 days or more past due and accruing	31,459	16,647
Purchased impaired	25,792	2,250
Other acquired impaired	21,924	13,374
Nonaccrual	150,702	173,365
Loans and leases, net of unearned discount	15,218,502	13,390,610
Commercial Real Estate Excluding Residential Builder and Developer and Other Construction [Member]
Summary of current, past due and nonaccrual loans
Current	18,746,145	16,589,240
30-89 days past due	197,412	89,906
90 days or more past due and accruing	19,207	35,338
Purchased impaired	207,523	8,275
Other acquired impaired	82,815	24,670
Nonaccrual	182,953	184,361
Loans and leases, net of unearned discount	19,436,055	16,931,790
Residential builder and developer [Member]
Summary of current, past due and nonaccrual loans
Current	813,855	891,764
30-89 days past due	116,705	30,805
90 days or more past due and accruing	32,767	9,763
Purchased impaired	338,182	72,710
Other acquired impaired	49,483	29,637
Nonaccrual	318,957	316,811
Loans and leases, net of unearned discount	1,669,949	1,351,490
Other commercial construction [Member]
Summary of current, past due and nonaccrual loans
Current	2,600,321	2,723,399
30-89 days past due	57,034	36,420
90 days or more past due and accruing	1,972	11,323
Purchased impaired	67,045	2,098
Other acquired impaired	24,035	10,376
Nonaccrual	104,895	116,265
Loans and leases, net of unearned discount	2,855,302	2,899,881
Residential real estate excluding Alt-A [Member]
Summary of current, past due and nonaccrual loans
Current	5,787,582	4,699,711
30-89 days past due	261,641	229,641
90 days or more past due and accruing	218,434	192,276
Purchased impaired	59,120	9,320
Other acquired impaired	25,724	10,728
Nonaccrual	165,058	162,001
Loans and leases, net of unearned discount	6,517,559	5,303,677
Residential Alt-A [Member]
Summary of current, past due and nonaccrual loans
Current	415,267	475,236
30-89 days past due	23,832	42,674
90 days or more past due and accruing	0	0
Purchased impaired	0	0
Other acquired impaired	0	0
Nonaccrual	108,793	106,469
Loans and leases, net of unearned discount	547,892	624,379
Home equity lines and loans [Member]
Summary of current, past due and nonaccrual loans
Current	6,671,948	6,472,563
30-89 days past due	45,028	38,367
90 days or more past due and accruing	0	0
Purchased impaired	4,794	2,366
Other acquired impaired	12,607	9,692
Nonaccrual	41,593	33,363
Loans and leases, net of unearned discount	6,775,970	6,556,351
Automobile [Member]
Summary of current, past due and nonaccrual loans
Current	2,691,109	2,608,230
30-89 days past due	49,756	44,604
90 days or more past due and accruing	0	0
Purchased impaired	0	0
Other acquired impaired	777	26
Nonaccrual	27,032	31,866
Loans and leases, net of unearned discount	2,768,674	2,684,726
Other [Member]
Summary of current, past due and nonaccrual loans
Current	2,531,909	2,190,353
30-89 days past due	57,950	36,689
90 days or more past due and accruing	6,127	4,246
Purchased impaired	1,176	0
Other acquired impaired	394	951
Nonaccrual	13,805	15,239
Loans and leases, net of unearned discount	$ 2,611,361	$ 2,247,478