Income Taxes Components of Income Tax Provision (Details) - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Components of income tax provision [Line Items]
Current Federal Tax Expense (Benefit)		$ 707	$ 365	$ (158)
Current State and Local Tax Expense (Benefit)		36	29	(15)
Current Income Tax Expense (Benefit)		743	394	(173)
Deferred Federal Income Tax Expense (Benefit)		27	99	444
Deferred State and Local Income Tax Expense (Benefit)		(6)	0	51
Deferred Income Tax Expense (Benefit)		21	99	495
Income Tax Expense (Benefit)	[1],[2]	$ 764	$ 493	$ 322

[1] Amortization expense related to qualified affordable housing investment costs is recognized in provision for income taxes for each of the periods presented as allowed by an accounting standard adopted in 2014. Accordingly, $49 million of related amortization expense for the year ended December 31, 2013 was reclassified from other noninterest expense to provision for income taxes.

[2] Amortization expense related to qualified affordable housing investment costs is recognized in the provision for income taxes for each of the periods presented as allowed by an accounting standard adopted in 2014. Prior to 2014, these amounts were recognized in other noninterest expense.