Asset Quality (Analysis of Loan Portfolio) (Details) - USD ($)	Jun. 30, 2015		Dec. 31, 2014		Jun. 30, 2014
Financing Receivable, Recorded Investment [Line Items]
Current or Less Than 30 Days Past Due	$ 196,553,000,000		$ 195,234,000,000
30-59 Days Past Due	492,000,000		582,000,000
60-89 Days Past Due	235,000,000		259,000,000
90 Days Or More Past Due	914,000,000		1,105,000,000
Total Past Due	1,641,000,000		1,946,000,000
Nonperforming loans	2,252,000,000		2,510,000,000
Fair Value Option Nonaccrual Loans	242,000,000		269,000,000
Purchased impaired loans	4,465,000,000		4,858,000,000		$ 5,557,000,000
Total loans	205,153,000,000	[1],[2]	204,817,000,000	[1],[2]	200,984,000,000
Unearned income, net deferred loan fees, unamortized discounts and premiums, and purchase discounts and premiums	$ 1,600,000,000		$ 1,700,000,000
Current or Less Than 30 Days Past Due [Member]
Financing Receivable, Recorded Investment [Line Items]
Percentage of total loans	95.80%		95.32%
30-59 Days Past Due [Member]
Financing Receivable, Recorded Investment [Line Items]
Percentage of total loans	0.24%		0.28%
60-89 Days Past Due [Member]
Financing Receivable, Recorded Investment [Line Items]
Percentage of total loans	0.11%		0.13%
90 Days Or More Past Due [Member]
Financing Receivable, Recorded Investment [Line Items]
Percentage of total loans	0.45%		0.54%
Total Past Due [Member]
Financing Receivable, Recorded Investment [Line Items]
Percentage of total loans	0.80%		0.95%
Nonperforming Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Percentage of total loans	1.10%		1.23%
Fair Value Option Nonaccrual Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Percentage of total loans	0.12%		0.13%
Purchased Impaired [Member]
Financing Receivable, Recorded Investment [Line Items]
Percentage of total loans	2.18%		2.37%
Total Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Percentage of total loans	100.00%		100.00%
Total commercial lending [Member]
Financing Receivable, Recorded Investment [Line Items]
Current or Less Than 30 Days Past Due	$ 129,821,000,000		$ 127,261,000,000
30-59 Days Past Due	90,000,000		107,000,000
60-89 Days Past Due	37,000,000		27,000,000
90 Days Or More Past Due	36,000,000		37,000,000
Total Past Due	163,000,000		171,000,000
Nonperforming loans	503,000,000		626,000,000
Purchased impaired loans	235,000,000		310,000,000		479,000,000
Total loans	130,722,000,000		128,368,000,000		124,083,000,000
Total consumer lending [Member]
Financing Receivable, Recorded Investment [Line Items]
Current or Less Than 30 Days Past Due	66,732,000,000		67,973,000,000
30-59 Days Past Due	402,000,000		475,000,000
60-89 Days Past Due	198,000,000		232,000,000
90 Days Or More Past Due	878,000,000		1,068,000,000
Total Past Due	1,478,000,000		1,775,000,000
Nonperforming loans	1,749,000,000		1,884,000,000
Fair Value Option Nonaccrual Loans	242,000,000		269,000,000
Purchased impaired loans	4,230,000,000		4,548,000,000		5,078,000,000
Total loans	74,431,000,000		76,449,000,000		$ 76,901,000,000
Commercial [Member] | Total commercial lending [Member]
Financing Receivable, Recorded Investment [Line Items]
Current or Less Than 30 Days Past Due	97,675,000,000		96,922,000,000
30-59 Days Past Due	83,000,000		73,000,000
60-89 Days Past Due	32,000,000		24,000,000
90 Days Or More Past Due	35,000,000		37,000,000
Total Past Due	150,000,000		134,000,000
Nonperforming loans	258,000,000		290,000,000
Purchased impaired loans	50,000,000		74,000,000
Total loans	98,133,000,000		97,420,000,000
Commercial Real Estate [Member] | Total commercial lending [Member]
Financing Receivable, Recorded Investment [Line Items]
Current or Less Than 30 Days Past Due	24,368,000,000		22,667,000,000
30-59 Days Past Due	5,000,000		23,000,000
60-89 Days Past Due	5,000,000		2,000,000
90 Days Or More Past Due	1,000,000
Total Past Due	11,000,000		25,000,000
Nonperforming loans	242,000,000		334,000,000
Purchased impaired loans	185,000,000		236,000,000
Total loans	24,806,000,000		23,262,000,000
Equipment Lease Financing [Member] | Total commercial lending [Member]
Financing Receivable, Recorded Investment [Line Items]
Current or Less Than 30 Days Past Due	7,778,000,000		7,672,000,000
30-59 Days Past Due	2,000,000		11,000,000
60-89 Days Past Due			1,000,000
Total Past Due	2,000,000		12,000,000
Nonperforming loans	3,000,000		2,000,000
Total loans	7,783,000,000		7,686,000,000
Home Equity [Member] | Total consumer lending [Member]
Financing Receivable, Recorded Investment [Line Items]
Current or Less Than 30 Days Past Due	30,555,000,000		31,474,000,000
30-59 Days Past Due	65,000,000		70,000,000
60-89 Days Past Due	25,000,000		32,000,000
Total Past Due	90,000,000		102,000,000
Nonperforming loans	1,057,000,000		1,112,000,000
Purchased impaired loans	1,833,000,000		1,989,000,000
Total loans	33,535,000,000		34,677,000,000
Residential Real Estate [Member] | Total consumer lending [Member]
Financing Receivable, Recorded Investment [Line Items]
Current or Less Than 30 Days Past Due	10,456,000,000		9,900,000,000
30-59 Days Past Due	142,000,000		163,000,000
60-89 Days Past Due	58,000,000		68,000,000
90 Days Or More Past Due	604,000,000		742,000,000
Total Past Due	804,000,000		973,000,000
Nonperforming loans	633,000,000		706,000,000
Fair Value Option Nonaccrual Loans	242,000,000		269,000,000
Purchased impaired loans	2,397,000,000		2,559,000,000
Total loans	14,532,000,000		14,407,000,000
Residential Real Estate [Member] | Total consumer lending [Member] | 30-59 Days Past Due [Member]
Financing Receivable, Recorded Investment [Line Items]
Government insured or guaranteed loans included in past due loans	64,000,000		68,000,000
Residential Real Estate [Member] | Total consumer lending [Member] | 60-89 Days Past Due [Member]
Financing Receivable, Recorded Investment [Line Items]
Government insured or guaranteed loans included in past due loans	38,000,000		43,000,000
Residential Real Estate [Member] | Total consumer lending [Member] | 90 Days Or More Past Due [Member]
Financing Receivable, Recorded Investment [Line Items]
Government insured or guaranteed loans included in past due loans	585,000,000		719,000,000
Credit Card [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	4,520,000,000		4,612,000,000
Credit Card [Member] | Total consumer lending [Member]
Financing Receivable, Recorded Investment [Line Items]
Current or Less Than 30 Days Past Due	4,448,000,000		4,528,000,000
30-59 Days Past Due	23,000,000		28,000,000
60-89 Days Past Due	17,000,000		20,000,000
90 Days Or More Past Due	29,000,000		33,000,000
Total Past Due	69,000,000		81,000,000
Nonperforming loans	3,000,000		3,000,000
Total loans	4,520,000,000		4,612,000,000
Other Consumer [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	21,844,000,000		22,753,000,000
Other Consumer [Member] | Total consumer lending [Member]
Financing Receivable, Recorded Investment [Line Items]
Current or Less Than 30 Days Past Due	21,273,000,000		22,071,000,000
30-59 Days Past Due	172,000,000		214,000,000
60-89 Days Past Due	98,000,000		112,000,000
90 Days Or More Past Due	245,000,000		293,000,000
Total Past Due	515,000,000		619,000,000
Nonperforming loans	56,000,000		63,000,000
Total loans	21,844,000,000		22,753,000,000
Other Consumer [Member] | Total consumer lending [Member] | 30-59 Days Past Due [Member]
Financing Receivable, Recorded Investment [Line Items]
Government insured or guaranteed loans included in past due loans	121,000,000		152,000,000
Other Consumer [Member] | Total consumer lending [Member] | 60-89 Days Past Due [Member]
Financing Receivable, Recorded Investment [Line Items]
Government insured or guaranteed loans included in past due loans	81,000,000		93,000,000
Other Consumer [Member] | Total consumer lending [Member] | 90 Days Or More Past Due [Member]
Financing Receivable, Recorded Investment [Line Items]
Government insured or guaranteed loans included in past due loans	$ 232,000,000		$ 277,000,000

[1] Amounts represent items for which we have elected the fair value option.

[2] Amounts represent the assets or liabilities of consolidated variable interest entities (VIEs).