Loans and Allowance for Credit Losses, Allowance for Credit Losses (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Dec. 31, 2014	Jun. 30, 2014
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Allowance for credit losses, beginning balance	$ 13,013	$ 14,414	$ 13,169	$ 14,971
Provision for credit losses	300	217	908	542
Interest income on certain impaired loans	(50)	(55)	(102)	(111)
Loan charge-offs	(1,041)	(1,161)	(2,137)	(2,445)
Loan recoveries	391	444	779	903
Net loan charge-offs	(650)	(717)	(1,358)	(1,542)
Allowances related to business combinations/other	1	(25)	(3)	(26)
Allowance for credit losses, ending balance	12,614	13,834	12,614	13,834
Components:
Allowance for loan losses					$ 11,754	$ 12,319	$ 13,101
Allowance for unfunded credit commitments					860		733
Total allowance for credit losses	$ 13,013	$ 14,414	$ 13,169	$ 14,971	$ 12,614	13,169	$ 13,834
Net loan charge-offs (annualized) as a percentage of average total loans	0.30%	0.35%	0.32%	0.38%
Allowance for loan losses as a percentage of total loans					1.32%		1.58%
Allowance for credit losses as a percentage of total loans					1.42%		1.67%
Total Commercial [Member]
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Allowance for credit losses, beginning balance	$ 6,333	$ 6,354	$ 6,377	$ 6,103
Provision for credit losses	11	83	20	346
Interest income on certain impaired loans	(4)	(6)	(9)	(12)
Loan charge-offs	(174)	(168)	(334)	(356)
Loan recoveries	112	137	228	320
Net loan charge-offs	(62)	(31)	(106)	(36)
Allowances related to business combinations/other	1	0	(3)	(1)
Allowance for credit losses, ending balance	6,279	6,400	6,279	6,400
Components:
Total allowance for credit losses	6,333	6,354	6,377	6,103	$ 6,279	6,377	$ 6,400
Commercial and Industrial Loans [Member]
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Loan charge-offs	(154)	(146)	(287)	(309)
Loan recoveries	73	86	142	200
Commercial Real Estate Mortgage [Member]
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Loan charge-offs	(16)	(16)	(39)	(36)
Loan recoveries	31	26	65	68
Commercial Real Estate Construction [Member]
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Loan charge-offs	(1)	(3)	(2)	(4)
Loan recoveries	7	23	17	47
Lease Financing [Member]
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Loan charge-offs	(3)	(3)	(6)	(7)
Loan recoveries	1	2	4	5
Total Consumer [Member]
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Allowance for credit losses, beginning balance	6,680	8,060	6,792	8,868
Provision for credit losses	289	134	888	196
Interest income on certain impaired loans	(46)	(49)	(93)	(99)
Loan charge-offs	(867)	(993)	(1,803)	(2,089)
Loan recoveries	279	307	551	583
Net loan charge-offs	(588)	(686)	(1,252)	(1,506)
Allowances related to business combinations/other	0	(25)	0	(25)
Allowance for credit losses, ending balance	6,335	7,434	6,335	7,434
Components:
Total allowance for credit losses	6,680	8,060	6,792	8,868	$ 6,335	$ 6,792	$ 7,434
Real estate 1-4 family first mortgage [Member]
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Loan charge-offs	(119)	(193)	(249)	(416)
Loan recoveries	52	56	99	109
Real estate 1-4 family junior lien mortgage [Member]
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Loan charge-offs	(163)	(220)	(342)	(469)
Loan recoveries	69	60	125	117
Credit Card [Member]
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Loan charge-offs	(284)	(266)	(562)	(533)
Loan recoveries	41	55	80	91
Automobile [Member]
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Loan charge-offs	(150)	(143)	(345)	(323)
Loan recoveries	82	97	176	187
Other revolving credit and installment [Member]
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Loan charge-offs	(151)	(171)	(305)	(348)
Loan recoveries	$ 35	$ 39	$ 71	$ 79