AOCI (Reclassifications Out of Accumulated Other Comprehensive Income) (Detail) - USD ($) $ in Millions		3 Months Ended		6 Months Ended
		Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Reclassifications Out Of Accumulated Other Comprehensive Income [Line Items]
Income Before Income Taxes		$ 427	$ 417	$ 862	$ 902
Applicable income tax expense		98	108	206	232
Net income		333	315	660	676
Total Reclassifications For The Period
Reclassifications Out Of Accumulated Other Comprehensive Income [Line Items]
Net income		12	7	25	23
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		8	(6)	16	6
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	[1]	8	(6)	16	6
Income Before Income Taxes	[1]	8	(6)	16	6
Applicable income tax expense	[1]	(2)	2	(5)	(2)
Net income	[1]	6	(4)	11	4
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		12	19	26	35
Income Before Income Taxes	[1]	12	19	26	35
Applicable income tax expense	[1]	(4)	(6)	(9)	(12)
Net income	[1]	8	13	17	23
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	[1]	12	19	26	35
Amortization Of Defined Benefit Pension Items | Net Actuarial Loss
Reclassifications Out Of Accumulated Other Comprehensive Income [Line Items]
Net periodic pension cost	[1],[2]	(3)	(3)	(5)	(6)
Income Before Income Taxes	[1]	(3)	(3)	(5)	(6)
Applicable income tax expense	[1]	1	1	2	2
Net income	[1]	$ (2)	$ (2)	$ (3)	$ (4)

[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, 2015 for information on the computation of net periodic benefit cost .