Fair Value (Schedule Of Assets And Liabilities Measured At Fair Value By Class On A Recurring Basis) (Details) - USD ($)	Sep. 30, 2019	Dec. 31, 2018
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments, Fair Value Disclosure	$ 14,033,000,000	$ 14,737,000,000
Debt Securities, Trading, and Equity Securities, FV-NI	280,000,000	106,000,000
Assets, Fair Value Disclosure	15,283,000,000	15,619,000,000
Financial Instruments Sold, Not yet Purchased, at Fair Value	4,000,000	85,000,000
Financial and Nonfinancial Liabilities, Fair Value Disclosure	128,000,000	219,000,000
US Treasury Securities [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments, Fair Value Disclosure	12,664,000,000	13,425,000,000
Asset-backed Securities [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments, Fair Value Disclosure	25,000,000	21,000,000
Interest Rate Swaps For Customers [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Other Assets, Fair Value Disclosure	203,000,000	40,000,000
Other Liabilities, Fair Value Disclosure	13,000,000	36,000,000
Available-for-sale Securities [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments, Fair Value Disclosure	1,344,000,000	1,291,000,000
Derivatives [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Other Assets, Fair Value Disclosure	4,000,000	1,000,000
Other Liabilities, Fair Value Disclosure	1,000,000	1,000,000
Bank-owned life insurance [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Other Noninterest Bearing Investments Fair Value Disclosure	525,000,000	516,000,000
Private Equity Funds [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Other Noninterest Bearing Investments Fair Value Disclosure	108,000,000	102,000,000
Assets, Fair Value Disclosure	1,000,000	1,000,000
Interest-Only-Strip [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Other Assets, Fair Value Disclosure	19,000,000	18,000,000
Foreign Exchange Contract [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Other Assets, Fair Value Disclosure	3,000,000	4,000,000
Other Liabilities, Fair Value Disclosure	2,000,000	2,000,000
Fair Value, Inputs, Level 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments, Fair Value Disclosure	25,000,000	40,000,000
Debt Securities, Trading, and Equity Securities, FV-NI	127,000,000	14,000,000
Assets, Fair Value Disclosure	263,000,000	153,000,000
Financial Instruments Sold, Not yet Purchased, at Fair Value	4,000,000	85,000,000
Financial and Nonfinancial Liabilities, Fair Value Disclosure	114,000,000	182,000,000
Fair Value, Inputs, Level 1 [Member] | US Treasury Securities [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments, Fair Value Disclosure	25,000,000	40,000,000
Fair Value, Inputs, Level 1 [Member] | Derivatives [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Other Assets, Fair Value Disclosure	3,000,000	4,000,000
Other Liabilities, Fair Value Disclosure	2,000,000	2,000,000
Fair Value, Inputs, Level 1 [Member] | Private Equity Funds [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Other Noninterest Bearing Investments Fair Value Disclosure
Assets, Fair Value Disclosure	0	0
Fair Value, Inputs, Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments, Fair Value Disclosure	14,008,000,000	14,697,000,000
Debt Securities, Trading, and Equity Securities, FV-NI	153,000,000	92,000,000
Assets, Fair Value Disclosure	14,893,000,000	15,346,000,000
Financial Instruments Sold, Not yet Purchased, at Fair Value	0	0
Financial and Nonfinancial Liabilities, Fair Value Disclosure	14,000,000	37,000,000
Fair Value, Inputs, Level 2 [Member] | US Treasury Securities [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments, Fair Value Disclosure	12,639,000,000	13,385,000,000
Fair Value, Inputs, Level 2 [Member] | Asset-backed Securities [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments, Fair Value Disclosure	25,000,000	21,000,000
Fair Value, Inputs, Level 2 [Member] | Interest Rate Swaps For Customers [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Other Assets, Fair Value Disclosure	203,000,000	40,000,000
Other Liabilities, Fair Value Disclosure	13,000,000	36,000,000
Fair Value, Inputs, Level 2 [Member] | Derivative Interest Rate Related And Other [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Other Assets, Fair Value Disclosure	4,000,000	1,000,000
Other Liabilities, Fair Value Disclosure	1,000,000
Fair Value, Inputs, Level 2 [Member] | Available-for-sale Securities [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments, Fair Value Disclosure	1,344,000,000	1,291,000,000
Fair Value, Inputs, Level 2 [Member] | Derivatives [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Other Liabilities, Fair Value Disclosure		1,000,000
Fair Value, Inputs, Level 2 [Member] | Bank-owned life insurance [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Other Noninterest Bearing Investments Fair Value Disclosure	525,000,000	516,000,000
Fair Value, Inputs, Level 2 [Member] | Private Equity Funds [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Other Noninterest Bearing Investments Fair Value Disclosure
Assets, Fair Value Disclosure	0	0
Fair Value, Inputs, Level 3 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments, Fair Value Disclosure	0	0
Assets, Fair Value Disclosure	127,000,000	120,000,000
Financial Instruments Sold, Not yet Purchased, at Fair Value	0	0
Financial and Nonfinancial Liabilities, Fair Value Disclosure	0	0
Fair Value, Inputs, Level 3 [Member] | US Treasury Securities [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments, Fair Value Disclosure	0	0
Fair Value, Inputs, Level 3 [Member] | Asset-backed Securities [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments, Fair Value Disclosure
Fair Value, Inputs, Level 3 [Member] | Available-for-sale Securities [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments, Fair Value Disclosure
Fair Value, Inputs, Level 3 [Member] | Private Equity Funds [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Other Noninterest Bearing Investments Fair Value Disclosure	108,000,000	102,000,000
Assets, Fair Value Disclosure	1,000,000	1,000,000
Fair Value, Inputs, Level 3 [Member] | Interest-Only-Strip [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Other Assets, Fair Value Disclosure	19,000,000	18,000,000
Deferred Compensation Arrangement with Individual, by Type of Compensation, Pension and Other Postretirement Benefits [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Other Assets, Fair Value Disclosure	108,000,000	95,000,000
Other Liabilities, Fair Value Disclosure	108,000,000	95,000,000
Deferred Compensation Arrangement with Individual, by Type of Compensation, Pension and Other Postretirement Benefits [Member] | Fair Value, Inputs, Level 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Other Assets, Fair Value Disclosure		95,000,000
Deferred Compensation Arrangement with Individual, by Type of Compensation, Pension and Other Postretirement Benefits [Member] | Fair Value, Inputs, Level 1 [Member] | Warranty, Rights and Obligations, Fair Value Option [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Other Assets, Fair Value Disclosure	108,000,000
Other Liabilities, Fair Value Disclosure	108,000,000	95,000,000
Third Party Pricing Service [Member] | Fair Value, Inputs, Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments, Fair Value Disclosure	$ 0.94	$ 0.95