Other Assets (Details) - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2018	Dec. 31, 2017
Mutual Fund Investments	[1],[2]	$ 79	$ 49
Equity Securities, FV-NI	[1],[2],[3]	16	7
Federal Reserve Bank Stock	[1],[2]	403	403
Federal Home Loan Bank Stock	[1],[2]	227	15
Equity Securities without Readily Determinable Fair Value, Amount	[2],[3]	68	26
Net Investment in Lease		1,940	1,528
Bank Owned Life Insurance		1,627	1,411
Accrued Investment Income Receivable		1,106	880
Receivables from Customers		602	2,201
Defined Benefit Plan, Funded (Unfunded) Status of Plan		484	464
Prepaid Expense		231	319
Other Real Estate	[4]	54	57
Other Assets, Miscellaneous	[5]	432	467
Other Assets	[6],[7]	8,991	9,099
Reclassification of Equity Securities from Nommarketable to Marketable		22
Equity Securities, FV-NI, Gain (Loss)	[8]	(2)
Equity Securities without Readily Determinable Fair Value, Downward Price Adjustment, Annual Amount		0
Equity Securities without Readily Determinable Fair Value, Upward Price Adjustment, Annual Amount	[8]	30
Equity Securities, FV-NI, Realized Gain (Loss)		0
Equity Securities [Member]
Unrealized Gain (Loss) on Securities		28
Tax Credit Investments [Member]
Other Assets	[9]	$ 1,722	$ 1,272

[1] Beginning January 1, 2018, the Company reclassified equity securities previously presented in Securities AFS to Other assets on the Consolidated Balance Sheets. Prior periods have been revised to conform to the current presentation for comparability.

[2] Does not include equity securities held for trading purposes classified as Trading assets and derivative instruments or Trading liabilities and derivative instruments on the Company’s Consolidated Balance Sheets. See Note 5, “Trading Assets and Liabilities and Derivative Instruments,” for more information.

[3] During the second quarter of 2018, the Company reclassified $22 million of equity securities from nonmarketable to marketable equity securities due to readily determinable fair value information observed in active markets.

[4] Does not include foreclosed real estate related to loans insured by the FHA or guaranteed by the VA. Proceeds due from the FHA and the VA are recorded as a receivable in Other assets in the Consolidated Balance Sheets until the property is conveyed and the funds are received. The receivable related to proceeds due from the FHA and the VA totaled $50 million and $45 million at December 31, 2018 and 2017, respectively.

[5] Beginning October 1, 2018, the Company reclassified capitalized software and related accumulated amortization previously presented in Other assets to Premises, property, and equipment, net, on the Consolidated Balance Sheets. Prior periods have been revised to conform to the current presentation for comparability.

[6] Beginning January 1, 2018, the Company reclassified equity securities previously presented in Securities available for sale to Other assets. Reclassifications have been made to previously reported amounts for comparability.

[7] Beginning October 1, 2018, the Company reclassified software and related accumulated amortization previously presented in Other assets to Premises, property, and equipment, net. Reclassifications have been made to previously reported amounts for comparability.

[8] Recognized in Other noninterest income in the Company's Consolidated Statements of Income.

[9] See Note 12, “Certain Transfers of Financial Assets and Variable Interest Entities,” for additional information.