Parent Company Financial Statements - Condensed Statement of Cash Flow - Parent Company Only (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Operating Activities
Net Income	$ 2,446	$ 2,770	$ 1,427
Adjustments to reconcile net income to net cash provided by operating activities:
(Benefit from) provision for deferred income taxes	(60)	(14)	(162)
Equity in undistributed earnings	(22)	(30)	(12)
Net change in:
Equity securities	70	15	12
Other assets	646	(37)	(855)
Net Cash Provided by Operating Activities	6,428	2,704	371
Investing Activities
AFS securities and other investments	(29,714)	(11,713)	(5,266)
Other short-term investments	26,224	(1,172)	(31,446)
Net Cash Used in Investing Activities	(4,871)	(7,968)	(31,902)
Financing Activities
Proceeds from issuance of long-term debt	4,026	562	2,557
Repayment of long-term debt	(1,762)	(3,603)	(2,799)
Dividends paid on common and preferred stock	(927)	(897)	(858)
Repurchase of treasury stock and related forward contract	(100)	(1,393)	0
Issuance of preferred stock	0	0	346
Other, net	(85)	(99)	(47)
Net Cash (Used in) Provided by Financing Activities	(1,085)	5,111	31,400
Increase (Decrease) in Cash and Due from Banks	472	(153)	(131)
Parent Company
Operating Activities
Net Income	2,446	2,770	1,427
Adjustments to reconcile net income to net cash provided by operating activities:
Amortization and accretion	7	7	7
(Benefit from) provision for deferred income taxes	(3)	(1)	0
Securities losses (gains), net	9	(1)	(1)
Equity in undistributed earnings	(2,533)	64	(351)
Net change in:
Equity securities	6	1	0
Other assets	(115)	(40)	(1)
Accrued expenses and other liabilities	45	(80)	0
Net Cash Provided by Operating Activities	(138)	2,720	1,081
Investing Activities
AFS securities and other investments	(1,000)	0	0
Other short-term investments	567	(656)	(855)
Loans to nonbank subsidiaries	132	158	94
Net Cash Used in Investing Activities	(301)	(498)	(761)
Financing Activities
Net change in other short-term borrowings	(240)	(89)	91
Proceeds from issuance of long-term debt	2,986	498	1,243
Repayment of long-term debt	(1,200)	(250)	(1,100)
Dividends paid on common and preferred stock	(927)	(897)	(858)
Repurchase of treasury stock and related forward contract	(100)	(1,393)	0
Issuance of preferred stock	0	0	346
Other, net	(82)	(89)	(40)
Net Cash (Used in) Provided by Financing Activities	437	(2,220)	(318)
Increase (Decrease) in Cash and Due from Banks	(2)	2	2
Cash and Due from Banks at Beginning of Period	122	120	118
Cash and Due from Banks at End of Period	$ 120	$ 122	$ 120