Other Assets Other Assests (Details) - USD ($) $ in Millions		3 Months Ended
		Mar. 31, 2018	Dec. 31, 2017
Mutual Fund Investments	[1]	$ 135	$ 49
Marketable Securities, Equity Securities	[1]	8	7
Securities Owned Not Readily Marketable		52	26
Federal Home Loan Bank Stock	[1]	15	15
Federal Reserve Bank Stock	[1]	403	403
Net Investment in Lease		1,567	1,528
Bank Owned Life Insurance		1,402	1,411
Accrued Investment Income Receivable		936	880
Receivables from Customers		768	2,201
Defined Benefit Plan, Funded (Unfunded) Status of Plan		476	464
Prepaid Expense		279	319
Other Real Estate		59	57
Other Assets, Miscellaneous		796	727
Other Assets	[2]	8,279	9,418
Other Assets [Member] | Security Owned Not Readily Marketable, Name [Domain]
Assets, Fair Value Adjustment		23
Asset Impairment Charges		0
Community Development Investments [Member]
Other Assets	[3]	$ 1,383	$ 1,331

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

[2] Text selection found with no content.

[3] See Note 10, "Certain Transfers of Financial Assets and Variable Interest Entities," for additional information.