Accumulated Other Comprehensive (Loss) Income - Schedule of Pretax and After-tax Components of Other Comprehensive Income (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Accumulated Other Comprehensive Income (Loss) [Line Items]
AOCI activity before reclassification, net of income taxes	$ (755)	$ 4
Reclassification from AOCI, net of income taxes	10	(6)
Other comprehensive (loss) income, pretax	(980)	(3)
Other comprehensive (loss) income, income taxes	235	1
Other comprehensive (loss) income, net of tax	(745)	(2)	$ 139
Defined benefit pension items
Accumulated Other Comprehensive Income (Loss) [Line Items]
AOCI activity before reclassification, pretax	(33)	98
AOCI activity before reclassification, income taxes	8	(22)
AOCI activity before reclassification, net of income taxes	(25)	76
Reclassification from AOCI, net of income taxes	9	21
Other comprehensive (loss) income, pretax	(21)	125
Other comprehensive (loss) income, income taxes	5	(28)
Other comprehensive (loss) income, net of tax	(16)	97
Defined benefit pension items | Other noninterest expense
Accumulated Other Comprehensive Income (Loss) [Line Items]
Reclassification from AOCI, pretax	12	27
Reclassification from AOCI, income taxes	(3)	(6)
Reclassification from AOCI, net of income taxes	9	21
Unrealized loss on securities available for sale transferred to securities held to maturity
Accumulated Other Comprehensive Income (Loss) [Line Items]
AOCI activity before reclassification, pretax	0	(13)
AOCI activity before reclassification, income taxes	0	3
AOCI activity before reclassification, net of income taxes	0	(10)
Reclassification from AOCI, net of income taxes	1	(1)
Other comprehensive (loss) income, pretax	1	(14)
Other comprehensive (loss) income, income taxes	0	3
Other comprehensive (loss) income, net of tax	1	(11)
Unrealized loss on securities available for sale transferred to securities held to maturity | Interest on investment securities
Accumulated Other Comprehensive Income (Loss) [Line Items]
Reclassification from AOCI, pretax	1	(1)
Reclassification from AOCI, income taxes	0	0
Reclassification from AOCI, net of income taxes	1	(1)
Unrealized (loss) gain on securities available for sale
Accumulated Other Comprehensive Income (Loss) [Line Items]
AOCI activity before reclassification, pretax	(960)	(81)
AOCI activity before reclassification, income taxes	230	19
AOCI activity before reclassification, net of income taxes	(730)	(62)
Reclassification from AOCI, net of income taxes	0	(26)
Other comprehensive (loss) income, pretax	(960)	(114)
Other comprehensive (loss) income, income taxes	230	26
Other comprehensive (loss) income, net of tax	(730)	(88)
Unrealized (loss) gain on securities available for sale | Realized gain on sale of investment securities available for sale, net
Accumulated Other Comprehensive Income (Loss) [Line Items]
Reclassification from AOCI, pretax	0	(33)
Reclassification from AOCI, income taxes	0	7
Reclassification from AOCI, net of income taxes	$ 0	$ (26)