Revenue Recognition (Details) - USD ($) $ in Millions		3 Months Ended				9 Months Ended
		Sep. 30, 2018		Sep. 30, 2017		Sep. 30, 2018		Sep. 30, 2017
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax		$ 508		$ 530		$ 1,514		$ 1,571
Fees and Commissions, Mortgage Banking and Servicing		43	[1]	46	[2]	138	[3]	148	[4]
Investment Banking Revenue	[5]	150	[1]	169	[2]	453	[3]	501	[4]
Trading Gain (Loss)		42	[1]	51	[2]	137	[3]	148	[4]
commercial real estate related income		24	[1]	17	[2]	66	[3]	61	[4]
Debt and Equity Securities, Gain (Loss)		0	[1]	0	[2]	1	[3]	1	[4]
Noninterest Income, Other Operating Income		21	[1]	25	[2]	108	[3]	76	[4]
Noninterest Income		782	[1]	846	[2],[6],[7]	2,408	[3]	2,520	[4],[8],[9]
Contract with Customer, Performance Obligation Satisfied in Previous Period		12				38
Deposit Account [Member]
Disaggregation of Revenue [Line Items]
Revenues		144	[1]	154	[2]	433	[3]	453	[4]
Financial Service, Other [Member]
Disaggregation of Revenue [Line Items]
Revenues	[5]	89	[1]	89	[2]	264	[3]	270	[4]
Credit and Debit Card [Member]
Disaggregation of Revenue [Line Items]
Revenues		75	[1]	86	[2]	241	[3]	255	[4]
Fiduciary and Trust [Member]
Disaggregation of Revenue [Line Items]
Revenues		80	[1]	79	[2]	230	[3]	229	[4]
Investment Advisory, Management and Administrative Service [Member]
Disaggregation of Revenue [Line Items]
Revenues		74	[1]	69	[2]	219	[3]	208	[4]
Mortgage Banking [Member]
Disaggregation of Revenue [Line Items]
Revenues		40	[1]	61	[2]	118	[3]	170	[4]
Excluded from Scope of ASC 606 - Consumer [Member]
Disaggregation of Revenue [Line Items]
Noninterest Income		100		123		313		365
Excluded from Scope of ASC 606 - Wholesale [Member]
Disaggregation of Revenue [Line Items]
Noninterest Income		210		226		646		660
Excluded from Scope of ASC 606 - Corporate Other [Member]
Disaggregation of Revenue [Line Items]
Noninterest Income		36		33		65		76
In Scope of ASC 606 - Consumer [Member]
Disaggregation of Revenue [Line Items]
Fees and Commissions, Mortgage Banking and Servicing		0	[1],[10]	0	[2],[11]	0	[3],[12]	0	[4],[13]
Investment Banking Revenue		0	[1],[10]	0	[2],[11]	0	[3],[12]	0	[4],[13]
Trading Gain (Loss)		0	[1],[10]	0	[2],[11]	0	[3],[12]	0	[4],[13]
commercial real estate related income		0	[1],[10]	0	[2],[11]	0	[3],[12]	0	[4],[13]
Debt and Equity Securities, Gain (Loss)		0	[1],[10]	0	[2],[11]	0	[3],[12]	0	[4],[13]
Noninterest Income, Other Operating Income		5	[1],[10]	6	[2],[11]	17	[3],[12]	20	[4],[13]
Noninterest Income		345	[1],[10]	359	[2],[11]	1,036	[3],[12]	1,062	[4],[13]
In Scope of ASC 606 - Consumer [Member] | Deposit Account [Member]
Disaggregation of Revenue [Line Items]
Revenues		111	[1],[10]	119	[2],[11]	330	[3],[12]	344	[4],[13]
In Scope of ASC 606 - Consumer [Member] | Financial Service, Other [Member]
Disaggregation of Revenue [Line Items]
Revenues		28	[1],[10]	29	[2],[11]	85	[3],[12]	93	[4],[13]
In Scope of ASC 606 - Consumer [Member] | Credit and Debit Card [Member]
Disaggregation of Revenue [Line Items]
Revenues		49	[1],[10]	58	[2],[11]	160	[3],[12]	172	[4],[13]
In Scope of ASC 606 - Consumer [Member] | Fiduciary and Trust [Member]
Disaggregation of Revenue [Line Items]
Revenues		79	[1],[10]	78	[2],[11]	228	[3],[12]	227	[4],[13]
In Scope of ASC 606 - Consumer [Member] | Investment Advisory, Management and Administrative Service [Member]
Disaggregation of Revenue [Line Items]
Revenues		73	[1],[10]	69	[2],[11]	216	[3],[12]	206	[4],[13]
In Scope of ASC 606 - Consumer [Member] | Mortgage Banking [Member]
Disaggregation of Revenue [Line Items]
Revenues		0	[1],[10]	0	[2],[11]	0	[3],[12]	0	[4],[13]
In Scope of ASC 606 - Wholesale [Member]
Disaggregation of Revenue [Line Items]
Fees and Commissions, Mortgage Banking and Servicing		0	[1],[10]	0	[2],[11]	0	[3],[12]	0	[4],[13]
Investment Banking Revenue		101	[1],[10]	106	[2],[11]	287	[3],[12]	309	[4],[13]
Trading Gain (Loss)		0	[1],[10]	0	[2],[11]	0	[3],[12]	0	[4],[13]
commercial real estate related income		0	[1],[10]	0	[2],[11]	0	[3],[12]	0	[4],[13]
Debt and Equity Securities, Gain (Loss)		0	[1],[10]	0	[2],[11]	0	[3],[12]	0	[4],[13]
Noninterest Income, Other Operating Income		0	[1],[10]	0	[2],[11]	0	[3],[12]	0	[4],[13]
Noninterest Income		163	[1],[10]	171	[2],[11]	478	[3],[12]	509	[4],[13]
In Scope of ASC 606 - Wholesale [Member] | Deposit Account [Member]
Disaggregation of Revenue [Line Items]
Revenues		33	[1],[10]	35	[2],[11]	103	[3],[12]	109	[4],[13]
In Scope of ASC 606 - Wholesale [Member] | Financial Service, Other [Member]
Disaggregation of Revenue [Line Items]
Revenues		3	[1],[10]	3	[2],[11]	8	[3],[12]	9	[4],[13]
In Scope of ASC 606 - Wholesale [Member] | Credit and Debit Card [Member]
Disaggregation of Revenue [Line Items]
Revenues		26	[1],[10]	27	[2],[11]	78	[3],[12]	81	[4],[13]
In Scope of ASC 606 - Wholesale [Member] | Fiduciary and Trust [Member]
Disaggregation of Revenue [Line Items]
Revenues		0	[1],[10]	0	[2],[11]	0	[3],[12]	0	[4],[13]
In Scope of ASC 606 - Wholesale [Member] | Investment Advisory, Management and Administrative Service [Member]
Disaggregation of Revenue [Line Items]
Revenues		0	[1],[10]	0	[2],[11]	2	[3],[12]	1	[4],[13]
In Scope of ASC 606 - Wholesale [Member] | Mortgage Banking [Member]
Disaggregation of Revenue [Line Items]
Revenues		0	[1],[10]	0	[2],[11]	0	[3],[12]	0	[4],[13]
Excluded from Scope of ASC 606 [Member]
Disaggregation of Revenue [Line Items]
Fees and Commissions, Mortgage Banking and Servicing		43	[1],[10],[14]	46	[2],[11],[15]	138	[3],[12],[16]	148	[4],[13],[17]
Investment Banking Revenue		49	[1],[10],[14]	63	[2],[11],[15]	166	[3],[12],[16]	192	[4],[13],[17]
Trading Gain (Loss)		42	[1],[10],[14]	51	[2],[11],[15]	137	[3],[12],[16]	148	[4],[13],[17]
commercial real estate related income		24	[1],[10],[14]	17	[2],[11],[15]	66	[3],[12],[16]	61	[4],[13],[17]
Debt and Equity Securities, Gain (Loss)		0	[1],[10],[14]	0	[2],[11],[15]	1	[3],[12],[16]	1	[4],[13],[17]
Noninterest Income, Other Operating Income		16	[1],[10],[14]	19	[2],[11],[15]	91	[3],[12],[16]	56	[4],[13],[17]
Noninterest Income		274	[1],[10],[14]	316	[2],[11],[15]	894	[3],[12],[16]	949	[4],[13],[17]
Excluded from Scope of ASC 606 [Member] | Deposit Account [Member]
Disaggregation of Revenue [Line Items]
Revenues		0	[1],[10],[14]	0	[2],[11],[15]	0	[3],[12],[16]	0	[4],[13],[17]
Excluded from Scope of ASC 606 [Member] | Financial Service, Other [Member]
Disaggregation of Revenue [Line Items]
Revenues		58	[1],[10],[14]	57	[2],[11],[15]	171	[3],[12],[16]	168	[4],[13],[17]
Excluded from Scope of ASC 606 [Member] | Credit and Debit Card [Member]
Disaggregation of Revenue [Line Items]
Revenues		0	[1],[10],[14]	1	[2],[11],[15]	3	[3],[12],[16]	2	[4],[13],[17]
Excluded from Scope of ASC 606 [Member] | Fiduciary and Trust [Member]
Disaggregation of Revenue [Line Items]
Revenues		1	[1],[10],[14]	1	[2],[11],[15]	2	[3],[12],[16]	2	[4],[13],[17]
Excluded from Scope of ASC 606 [Member] | Investment Advisory, Management and Administrative Service [Member]
Disaggregation of Revenue [Line Items]
Revenues		1	[1],[10],[14]	0	[2],[11],[15]	1	[3],[12],[16]	1	[4],[13],[17]
Excluded from Scope of ASC 606 [Member] | Mortgage Banking [Member]
Disaggregation of Revenue [Line Items]
Revenues		$ 40	[1],[10],[14]	$ 61	[2],[11],[15]	$ 118	[3],[12],[16]	$ 170	[4],[13],[17]

[1] Amounts are presented in accordance with ASC Topic 606, Revenue from Contracts with Customers, except for out of scope amounts.

[2] Amounts for periods prior to January 1, 2018 are presented in accordance with ASC Topic 605, Revenue Recognition, and have not been restated to conform with ASC Topic 606, Revenue from Contracts with Customers.

[3] Amounts are presented in accordance with ASC Topic 606, Revenue from Contracts with Customers, except for out of scope amounts.

[4] Amounts for periods prior to January 1, 2018 are presented in accordance with ASC Topic 605, Revenue Recognition, and have not been restated to conform with ASC Topic 606, Revenue from Contracts with Customers.

[5] Beginning July 1, 2018, the Company began presenting bridge commitment fee income related to capital market transactions in Investment banking income on the Consolidated Statements of Income. For periods prior to July 1, 2018, this income was previously presented in Other charges and fees and has been reclassified to Investment banking income for comparability.

[6] During the fourth quarter of 2017, the Company sold PAC, the results of which were previously reported within the Wholesale business segment. For all periods prior to January 1, 2018, PAC's financial results, including the gain on sale, have been transferred to Corporate Other for enhanced comparability of the Wholesale business segment excluding PAC.

[7] During the second quarter of 2018, certain of the Company's business banking clients were transferred from the Wholesale business segment to the Consumer business segment. For all periods prior to the second quarter of 2018, the corresponding financial results have been transferred to the Consumer business segment for comparability purposes.

[8] During the fourth quarter of 2017, the Company sold PAC, the results of which were previously reported within the Wholesale business segment. For all periods prior to January 1, 2018, PAC's financial results, including the gain on sale, have been transferred to Corporate Other for enhanced comparability of the Wholesale business segment excluding PAC.

[9] During the second quarter of 2018, certain of the Company's business banking clients were transferred from the Wholesale business segment to the Consumer business segment. For all periods prior to the second quarter of 2018, the corresponding financial results have been transferred to the Consumer business segment for comparability purposes.

[10] Consumer total noninterest income and Wholesale total noninterest income exclude $100 million and $210 million of out of scope noninterest income, respectively, which are included in the business segment results presented on a management accounting basis in Note 18, "Business Segment Reporting." Out of scope total noninterest income includes these amounts and also includes ($36) million of Corporate Other noninterest income that is not subject to ASC Topic 606.

[11] Consumer total noninterest income and Wholesale total noninterest income exclude $123 million and $226 million of out of scope noninterest income, respectively, which are included in the business segment results presented on a management accounting basis in Note 18, "Business Segment Reporting." Out of scope total noninterest income includes these amounts and also includes ($33) million of Corporate Other noninterest income that is not subject to ASC Topic 606.

[12] Consumer total noninterest income and Wholesale total noninterest income exclude $313 million and $646 million of out of scope noninterest income, respectively, which are included in the business segment results presented on a management accounting basis in Note 18, "Business Segment Reporting." Out of scope total noninterest income includes these amounts and also includes ($65) million of Corporate Other noninterest income that is not subject to ASC Topic 606.

[13] Consumer total noninterest income and Wholesale total noninterest income exclude $365 million and $660 million of out of scope noninterest income, respectively, which are included in the business segment results presented on a management accounting basis in Note 18, "Business Segment Reporting." Out of scope total noninterest income includes these amounts and also includes ($76) million of Corporate Other noninterest income that is not subject to ASC Topic 606.

[14] The Company presents out of scope noninterest income for the purpose of reconciling noninterest income amounts within the scope of ASC Topic 606 to noninterest income amounts presented on the Company's Consolidated Statements of Income.

[15] The Company presents out of scope noninterest income for the purpose of reconciling noninterest income amounts within the scope of ASC Topic 606 to noninterest income amounts presented on the Company's Consolidated Statements of Income.

[16] The Company presents out of scope noninterest income for the purpose of reconciling noninterest income amounts within the scope of ASC Topic 606 to noninterest income amounts presented on the Company's Consolidated Statements of Income.

[17] The Company presents out of scope noninterest income for the purpose of reconciling noninterest income amounts within the scope of ASC Topic 606 to noninterest income amounts presented on the Company's Consolidated Statements of Income.