AOCI (Reclassification Out of Accumulated Other Comprehensive Income) (Detail) - USD ($) $ in Millions		3 Months Ended
		Mar. 31, 2020	Mar. 31, 2019
Reclassifications Out Of Accumulated Other Comprehensive Income
Reclassification adjustment for net losses (gains) included in net income			$ (1)
Reclassification adjustment for net gains on cash flow hedge derivatives included in net income		$ 32	(2)
Net periodic pension cost	[1],[2]	(1)	(1)
Income (Loss) Before Income Taxes		60	996
Applicable income tax expense		14	221
Net income		46	775
Total reclassifications for the period
Reclassifications Out Of Accumulated Other Comprehensive Income
Net income		24	(4)
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			(1)
Income (Loss) Before Income Taxes			(1)
Net income			(1)
Net unrealized gains on cash flow hedge derivatives
Reclassifications Out Of Accumulated Other Comprehensive Income
Reclassification adjustment for net gains on cash flow hedge derivatives included in net income		32	(2)
Income (Loss) Before Income Taxes		32	(2)
Applicable income tax expense		(7)
Net income		25	(2)
Amortization of defined periodic benefit costs
Reclassifications Out Of Accumulated Other Comprehensive Income
Income (Loss) Before Income Taxes		(1)	(1)
Net income		$ (1)	$ (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 24 of the Notes to Consolidated Financial Statements included in the Bancorp’s Annual Report on Form 10-K for the year ended December 31, 2019 for further information.