AOCI (Reclassifications Out of Accumulated Other Comprehensive Income) (Detail) - USD ($) $ in Millions		3 Months Ended		9 Months Ended
		Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Reclassifications Out Of Accumulated Other Comprehensive Income
Income Before Income Taxes		$ 694	$ 515	$ 1,556	$ 1,417
Applicable income tax expense		178	134	385	367
Net income		516	381	1,175	1,056
Total Reclassifications For The Period
Reclassifications Out Of Accumulated Other Comprehensive Income
Net income		3	18	26	39
Net Unrealized Gains On Available For Sale Securities
Reclassifications Out Of Accumulated Other Comprehensive Income
Reclassification adjustment for net losses (gains) included in net income		2	10	18	16
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	[1]	2	10	18	16
Income Before Income Taxes	[1]	2	10	18	16
Applicable income tax expense	[1]	(1)	(3)	(7)	(5)
Net income	[1]	1	7	11	11
Net Unrealized Gains On Cash Flow Hedge Activities
Reclassifications Out Of Accumulated Other Comprehensive Income
Reclassification adjustment for net gains on cash flow hedge derivatives included in net income		11	20	37	55
Income Before Income Taxes	[1]	11	20	37	55
Applicable income tax expense	[1]	(4)	(7)	(14)	(19)
Net income	[1]	7	13	23	36
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	[1]	11	20	37	55
Amortization Of Defined Benefit Pension Items
Reclassifications Out Of Accumulated Other Comprehensive Income
Income Before Income Taxes	[1]	(8)	(3)	(12)	(12)
Applicable income tax expense	[1]	3	1	4	4
Net income	[1]	(5)	(2)	(8)	(8)
Amortization Of Defined Benefit Pension Items | Net Actuarial Loss
Reclassifications Out Of Accumulated Other Comprehensive Income
Net periodic pension cost	[1],[2]	(2)	(2)	(7)	(7)
Amortization Of Defined Benefit Pension Items | Pension Settlement
Reclassifications Out Of Accumulated Other Comprehensive Income
Net periodic pension cost	[1],[2]	$ (6)	$ (1)	$ (5)	$ (5)

[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 .