Statements of Cash Flow - Parent Company Only (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017		Dec. 31, 2016		Dec. 31, 2015
Net Income (Loss) Attributable to Parent	$ 2,775	$ 2,273	[1],[2]	$ 1,878	[3],[4]
Depreciation, Amortization and Accretion, Net	716	727		725
Deferred Income Tax Expense (Benefit)	(87)	344		111
Stock Option Compensation And Amortization Of Restricted Stock Compensation	140	160		126
Debt and Equity Securities, Gain (Loss)	(1)	108		(4)
Net decrease/(increase) in other assets	(340)	348	[5]	(627)	[5]
Net increase/(decrease) in Other Operating Liabilities	(797)	(911)		(284)
Net Cash Provided by (Used in) Operating Activities, Continuing Operations	2,569	5,622		(518)
Proceeds from Maturities, Prepayments and Calls of Debt Securities, Available-for-sale	(3,690)	(4,186)		(5,108)
Proceeds from Sale of Available-for-sale Securities	(2,096)	(2,854)		(197)
Payments to Acquire Available-for-sale Securities	6,389	8,299		8,610
Net Cash Provided by (Used in) Investing Activities, Continuing Operations	10,151	2,998		11,307
Proceeds from Issuance of Long-term Debt	6,944	2,844		6,705
Repayments of Long-term Debt	(1,274)	(4,562)		(3,231)
Proceeds from Issuance of Preferred Stock and Preference Stock	0	1,239		0
Payments for Repurchase of Preferred Stock and Preference Stock	(450)	0		0
Payments for Repurchase of Common Stock	(1,910)	(1,314)		(806)
Payments for Repurchase of Warrants	0	0		(24)
Payments Related to Tax Withholding for Share-based Compensation	(45)	(39)		(48)
Proceeds from the exercise of stock options	36	21		25
Net Cash Provided by (Used in) Financing Activities, Continuing Operations	8,165	(2,135)		12,649
Cash and Cash Equivalents, Period Increase (Decrease)	583	489		824
Cash and cash equivalents	7,495	6,912		6,423		$ 5,599
Interest Paid, Including Capitalized Interest, Operating and Investing Activities	1,151	730		559
Parent Company [Member]
Net Income (Loss) Attributable to Parent	2,775	2,273		1,878
Equity in Undistributed Earnings of Subsidiaries	(521)	(1,024)		(725)
Depreciation, Amortization and Accretion, Net	3	5		3
Deferred Income Tax Expense (Benefit)	8	5		11
Stock Option Compensation And Amortization Of Restricted Stock Compensation	0	0		3
Debt and Equity Securities, Gain (Loss)	0	(1)		0
Net decrease/(increase) in other assets	(158)	(15)		(129)
Net increase/(decrease) in Other Operating Liabilities	26	122		62
Net Cash Provided by (Used in) Operating Activities, Continuing Operations	2,133	1,365		1,103
Proceeds from Maturities, Prepayments and Calls of Debt Securities, Available-for-sale	23	38		49
Proceeds from Sale of Available-for-sale Securities	0	1		4
Payments to Acquire Available-for-sale Securities	0	(17)		(4)
Payments for (Proceeds from) Loans Receivable	43	(1,298)		889
Payments for (Proceeds from) Other Investing Activities	1	0		3
Net Cash Provided by (Used in) Investing Activities, Continuing Operations	(21)	1,320		(843)
Proceeds from (Repayments of) Short-term Debt	(196)	(211)		5
Proceeds from Issuance of Long-term Debt	929	9		2,005
Repayments of Long-term Debt	(873)	(482)		(1,784)
Proceeds from Issuance of Preferred Stock and Preference Stock	0	1,239		0
Payments for Repurchase of Preferred Stock and Preference Stock	(450)	0		0
Payments for Repurchase of Common Stock	(1,910)	(1,314)		(806)
Payments for Repurchase of Warrants	0	0		(24)
Payments of Dividends	(936)	(723)		(564)
Payments Related to Tax Withholding for Share-based Compensation	(45)	(39)		(48)
Proceeds from the exercise of stock options	36	21		25
Net Cash Provided by (Used in) Financing Activities, Continuing Operations	(3,445)	(1,500)		(1,191)
Cash and Cash Equivalents, Period Increase (Decrease)	(1,333)	1,185		(931)
Cash and cash equivalents	1,536	2,869		1,684		$ 2,615
Income Taxes (Paid)/Received by Parent Company	(105)	414		812
Income Taxes Received From (Paid To) Subsidiaries	101	(489)		(886)
Income Taxes Paid, Net	(4)	(75)		(74)
Interest Paid, Including Capitalized Interest, Operating and Investing Activities	$ 164	$ 140		$ 135

[1] 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.

[2] 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.

[3] 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.

[4] 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.

[5] ertain prior period amounts have been revised to reflect the impact of the Company’s adoption of ASU 2016-15. See Note 1, “Significant Accounting Policies,” for additional information.