Accumulated Other Comprehensive Income Reclassifications out of AOCI (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2014		Mar. 31, 2013
Other Comprehensive Income (Loss), Reclassification Adjustment for Sale of Securities Included in Net Income, before Tax	$ 1		$ (2)
Other Comprehensive Income (Loss), Reclassification Adjustment for Sale of Securities Included in Net Income, Tax	0		1
Other Comprehensive Income (Loss), Reclassification Adjustment for Sale of Securities Included in Net Income, Net of Tax	1		(1)
Other Comprehensive Income (Loss), Reclassification Adjustment on Derivatives Included in Net Income, before Tax	(102)		(114)
Other Comprehensive Income (Loss), Reclassification Adjustment on Derivatives Included in Net Income, Tax	38		43
Other Comprehensive Income (Loss), Reclassification Adjustment on Derivatives Included in Net Income, Net of Tax	(64)		(71)
Other Comprehensive Income (Loss), Pension and Other Postretirement Benefit Plans, Adjustment, before Tax	49		32
Other Comprehensive Income (Loss), Pension and Other Postretirement Benefit Plans, Tax	(18)		(12)
Other Comprehensive Income (Loss), Pension and Other Postretirement Benefit Plans, Adjustment, Net of Tax	31		20
Other Assets And Liabilities, Net [Member]
Other Comprehensive Income (Loss), Pension and Other Postretirement Benefit Plans, Adjustment, before Tax	46	[1]	26	[1]
Net securities gains [Member]
Other Comprehensive Income (Loss), Reclassification Adjustment for Sale of Securities Included in Net Income, before Tax	1		(2)
provision for income taxes [Member]
Other Comprehensive Income (Loss), Reclassification Adjustment for Sale of Securities Included in Net Income, Tax	0		1
Other Comprehensive Income (Loss), Reclassification Adjustment on Derivatives Included in Net Income, Tax	38		43
Other Comprehensive Income (Loss), Pension and Other Postretirement Benefit Plans, Tax	(18)		(12)
Interest Income, Interest and Fees on Loans
Other Comprehensive Income (Loss), Reclassification Adjustment on Derivatives Included in Net Income, before Tax	(102)		(114)
employee benefits [Member]
Other Comprehensive Income (Loss), Pension and Other Postretirement Benefit Plans, Adjustment, before Tax	$ 3		$ 6

[1] This AOCI component is recognized as an adjustment to the funded status of employee benefit plans in the Company's Consolidated Balance Sheets. (For additional information, see Note 10, "Employee Benefit Plans" to the Consolidated Financial Statements in the Company's 2013 Annual Report on Form 10-K).