Reclassifications Out of Accumulated Other Comprehensive Income (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended			9 Months Ended
	Sep. 30, 2013		Sep. 30, 2012	Sep. 30, 2013		Sep. 30, 2012
Reclassifications Out Of Accumulated Other Comprehensive Income
Income Before Income Taxes	$ 604		$ 503	$ 2,037		$ 1,670
Applicable income tax expense	183		139	613		491
Net income	421		363	1,433		1,178
Net Unrealized Gains On Available For Sale Securities | Net Losses Included In Net Income
Reclassifications Out Of Accumulated Other Comprehensive Income
Reclassification adjustment for net losses (gains) included in net income	5	[1]		(53)	[1]
Income Before Income Taxes	5	[1]		(53)	[1]
Applicable income tax expense	(1)	[1]		19	[1]
Net income	4	[1]		(34)	[1]
Net Unrealized Gains On Cash Flow Hedge Activities
Reclassifications Out Of Accumulated Other Comprehensive Income
Income Before Income Taxes	6	[1]		37	[1]
Applicable income tax expense	(2)	[1]		(13)	[1]
Net income	4	[1]		24	[1]
Net Unrealized Gains On Cash Flow Hedge Activities | Interest Rate Contracts Related To C&I Loans
Reclassifications Out Of Accumulated Other Comprehensive Income
Reclassification adjustment for net gains on cash flow hedge derivatives included in net income	6	[1]		38	[1]
Net Unrealized Gains On Cash Flow Hedge Activities | Interest Rate Contracts Related To Long-Term Debt
Reclassifications Out Of Accumulated Other Comprehensive Income
Reclassification adjustment for net gains on cash flow hedge derivatives included in net income				(1)	[1]
Amortization Of Defined Benefit Pension Items | Net Actuarial Loss
Reclassifications Out Of Accumulated Other Comprehensive Income
Net periodic pension cost	(3)	[1],[2]		(9)	[1],[2]
Income Before Income Taxes	(3)	[1]		(9)	[1]
Applicable income tax expense	1	[1]		3	[1]
Net income	(2)	[1]		(6)	[1]
Total Reclassifications For The Period
Reclassifications Out Of Accumulated Other Comprehensive Income
Net income	$ 6	[1]		$ (16)	[1]

[1] Amounts in parentheses indicate reductions to net income

[2] This AOCI component is included in the computation of net periodic benefit cost. Refer to Note 20 in the Bancorp’s Annual Report on Form 10-K for the year ended December 31, 2012 for information on the computation of net periodic benefit cost.