Income Taxes (Narrative) (Details) - USD ($)	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Operating Loss Carryforwards [Line Items]
Unrecognized tax benefits that would favorably impact the effective tax rate	$ 20,000,000
Estimated change in balance of unrecognized tax benefits, within the next twelve months	4,000,000
Unrecognized tax benefits	26,000,000	$ 77,000,000	$ 110,000,000	$ 176,000,000
Undistributed Earnings Of Foreign Subsidiaries	110,000,000
Allocations For Bad Debt Deductions Of Former Thrift Subsidiaries Included In Retained Earnings	117,000,000	117,000,000
Income tax expense benefit - gross interest and penalties	46,000,000
Income Tax Examination Penalties And Interest Accrued		41,000,000
Deferred Tax Liability Not Recognized Amount Of Unrecognized Deferred Tax Liability	34,000,000
Cumulative effect of adopting ASU 2014-01 [Member] | Low Income Housing Tax Credit Investments [Member]
Operating Loss Carryforwards [Line Items]
Amortization recognized for low income housing tax credits associated with adoption of ASU 2014-01	202,000,000
Tax credits recognized for low income housing tax credits associated with adoption of ASU 2014-01	224,000,000
Other tax benefits recognized for low income housing tax credits associated with adoption of ASU 2014-01	74,000,000
State and Local Jurisdiction [Member]
Operating Loss Carryforwards [Line Items]
Net Operating Loss Carryforwards	2,272,000,000	2,594,000,000
Tax Credit Carryforward Valuation Allowance	$ 61,000,000
Operating Loss Carryforwards Earliest Expiration Date	2016
Operating Loss Carryforwards Latest Expiration Date	2035
Reduction of state net operating losses	$ 60,000,000
Internal Revenue Service (IRS) [Member]
Operating Loss Carryforwards [Line Items]
Net Operating Loss Carryforwards	$ 878,000,000	$ 997,000,000
Operating Loss Carryforwards Expiration Date	Dec. 31, 2032
Tax Credit Carryforward Expiration Date	Dec. 31, 2032
Income Tax Examination Earliest Year Complete	2007
Income Tax Examination Latest Year Complete	2010
Income Tax Examination Earliest Year Under Examination	2011
Income Tax Examination Latest Year Under Examination	2013
Internal Revenue Service (IRS) [Member] | National City Acquisition [Member]
Operating Loss Carryforwards [Line Items]
Income Tax Returns National City Year Settled	2008