Statements of Income/(Loss) - Parent Company Only (Details) - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2018	Dec. 31, 2017		Dec. 31, 2016
Interest and Dividend Income, Securities, Available-for-sale	[1],[2]	$ 849	$ 756		$ 636
Interest Expense, Long-term Debt		375	288		260
Income (Loss) from Continuing Operations before Equity Method Investments, Income Taxes, Extraordinary Items, Noncontrolling Interest		3,332	2,814		2,692
Income Tax Expense (Benefit)		(548)	(532)		(805)
Net Income (Loss) Attributable to Parent		2,775	2,273	[3],[4]	1,878	[5],[6]
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent		(446)	1	[7]	(356)
Comprehensive Income (Loss), Net of Tax, Attributable to Parent		2,329	2,274	[7]	1,522
Parent Company [Member]
Interest and Dividend Income, Securities, Available-for-sale	[8]	2,380	1,414		1,300
Interest and Fee Income, Other Loans		30	25		15
Interest Income, Deposits with Other Federal Home Loan Banks		25	22		12
Other Income		34	5		2
Revenues		2,469	1,466		1,329
Interest Expense, Short-term Borrowings		6	4		2
Interest Expense, Long-term Debt		161	137		140
Labor and Related Expense	[9]	40	103		57
Fees and Commission Expense		9	12		12
Other Expenses		19	33		24
Operating Expenses		235	289		235
Income (Loss) from Continuing Operations before Equity Method Investments, Income Taxes, Extraordinary Items, Noncontrolling Interest		2,234	1,177		1,094
Income Tax Expense (Benefit)		20	72		59
Income (Loss) Before Equity in Undistributed Earnings of Subsidiaries		2,254	1,249		1,153
Equity in Undistributed Earnings of Subsidiaries		521	1,024		725
Net Income (Loss) Attributable to Parent		2,775	2,273		1,878
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent		(446)	1		(356)
Comprehensive Income (Loss), Net of Tax, Attributable to Parent		$ 2,329	$ 2,274		$ 1,522

[1] Beginning January 1, 2018, the Company reclassified equity securities previously presented in Securities AFS to Other assets on the Consolidated Balance Sheets and began presenting income associated with certain of these equity securities in Trading account interest and other. For periods prior to January 1, 2018, this income was previously presented in Interest on securities available for sale and has been reclassified to Trading account interest and other for comparability.

[2] Beginning January 1, 2018, the Company reclassified equity securities previously presented in Securities AFS to Other assets on the Consolidated Balance Sheets and began presenting income associated with certain of these equity securities in Trading account interest and other on the Consolidated Statements of Income. For periods prior to January 1, 2018, this income was previously presented in Interest on securities available for sale and has been reclassified to Trading account interest and other for comparability.

[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] 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.

[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] Net of tax amounts include the stranded tax effects resulting from the 2017 Tax Act. See Note 1, "Significant Accounting Policies," for additional information.

[8] Substantially all dividend income is from subsidiaries (primarily the Bank).

[9] Includes incentive compensation allocations between the Parent Company and subsidiaries.