Fair Value (Schedule Of Assets And Liabilities Measured At Fair Value By Class On A Recurring Basis Using Level 3 Inputs) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016	Dec. 31, 2016
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Other Assets, Fair Value Disclosure	$ 95		$ 91
Other Liabilities, Fair Value Disclosure	95		91
Total net gains (losses) included in, Other noninterest expense	51	$ 50
Private Equity Investments [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair value of assets, Beginning balance	73	58
Total net gains (losses) included in, Dividends and other investment income
Total net gains (losses) included in, Equity securities gains, net	3	1
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Purchases	7	2
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Settlements	(5)
Fair value of assets, Ending balance	78	61
Servicing Contracts [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair value of liabilities, Beginning balance	20	14
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Noninterest Income		3
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Purchases
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Settlements
Fair value of liabilities, Ending balance	20	$ 17
Fair Value, Inputs, Level 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Other Assets, Fair Value Disclosure	95		91
Other Liabilities, Fair Value Disclosure	$ 95		$ 91