Reclassifications Out of Accumulated Other Comprehensive Income (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended				9 Months Ended
	Sep. 30, 2014		Sep. 30, 2013		Sep. 30, 2014		Sep. 30, 2013
Reclassifications Out Of Accumulated Other Comprehensive Income [Line Items]
Income Before Income Taxes	$ 464		$ 604		$ 1,509		$ 2,037
Applicable income tax expense	124		183		411		613
Net income	340		421		1,096		1,433
Total Reclassifications For The Period
Reclassifications Out Of Accumulated Other Comprehensive Income [Line Items]
Net income	9		6		33		(16)
Net Unrealized Gains On Available For Sale Securities
Reclassifications Out Of Accumulated Other Comprehensive Income [Line Items]
Reclassification adjustment for net losses (gains) included in net income	5		5		25		(53)
Net Unrealized Gains On Available For Sale Securities | Net Losses Included In Net Income
Reclassifications Out Of Accumulated Other Comprehensive Income [Line Items]
Reclassification adjustment for net losses (gains) included in net income	5	[1]	5	[1]	25	[1]	(53)	[1]
Income Before Income Taxes	5	[1]	5	[1]	25	[1]	(53)	[1]
Applicable income tax expense	(2)	[1]	(1)	[1]	(9)	[1]	19	[1]
Net income	3	[1]	4	[1]	16	[1]	(34)	[1]
Net Unrealized Gains On Cash Flow Hedge Activities
Reclassifications Out Of Accumulated Other Comprehensive Income [Line Items]
Reclassification adjustment for net gains on cash flow hedge derivatives included in net income	10		6		31		37
Income Before Income Taxes	10	[1]	6	[1]	31	[1]	37	[1]
Applicable income tax expense	(3)	[1]	(2)	[1]	(11)	[1]	(13)	[1]
Net income	7	[1]	4	[1]	20	[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 [Line Items]
Reclassification adjustment for net gains on cash flow hedge derivatives included in net income	10	[1]	6	[1]	31	[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 [Line Items]
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 [Line Items]
Net periodic pension cost	(2)	[1],[2]	(3)	[1],[2]	(5)	[1],[2]	(9)	[1],[2]
Income Before Income Taxes	(2)	[1]	(3)	[1]	(5)	[1]	(9)	[1]
Applicable income tax expense	1	[1]	1	[1]	2	[1]	3	[1]
Net income	$ (1)	[1]	$ (2)	[1]	$ (3)	[1]	$ (6)	[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 21 in the Bancorp’s Annual Report on Form 10-K for the year ended December 31, 2013 for information on the computation of net periodic benefit cost.