Consolidated Statement of Cash Flows - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Operating Activities:
Net income	$ 2,420	$ 2,242	$ 2,593
Adjustments to reconcile net income to net cash provided by operating activities:
Deferred income tax (benefit)	(194)	(130)	(136)
Amortization of other intangible assets	234	236	226
Other non-cash adjustments for depreciation, amortization and accretion, net	1,276	1,101	977
Losses (gains) related to investment securities, net	(4)	1	(6)
Provision for credit losses	88	10	15
Change in trading account assets, net	99	(54)	233
Change in accrued interest and fees receivable, net	127	(28)	26
Change in collateral deposits, net	(2,951)	287	7,326
Change in unrealized losses (gains) on foreign exchange derivatives, net	3,652	2,034	(1,836)
Change in other assets, net	(1,406)	(713)	(22)
Change in accrued expenses and other liabilities, net	(170)	294	394
Other, net	361	410	385
Net cash provided by operating activities	3,532	5,690	10,175
Investing Activities:
Net (increase) decrease in interest-bearing deposits with banks	(47,995)	4,075	(5,813)
Net (increase) decrease in securities purchased under resale agreements	(1,619)	3,192	(1,438)
Proceeds from sales of available-for-sale securities	2,645	5,642	26,082
Proceeds from maturities of available-for-sale securities	23,644	20,407	14,645
Purchases of available-for-sale securities	(37,873)	(38,164)	(31,814)
Purchases of held-to-maturity securities under the MMLF program	(29,242)	0	0
Proceeds from maturities of held-to-maturity securities under the MMLF program	25,984	0	0
Proceeds from maturities of held-to-maturity securities	15,179	10,390	6,296
Purchases of held-to-maturity securities	(13,981)	(6,938)	(6,539)
Sale of loans	324	131	278
Net (increase) in loans and leases	(1,939)	(650)	(2,739)
Business acquisitions, net of cash acquired	0	(54)	(2,595)
Purchases of equity investments and other long-term assets	(1,436)	(647)	(326)
Purchases of premises and equipment, net	(560)	(730)	(609)
Other, net	1,335	720	76
Net cash (used in) by investing activities	(65,534)	(2,626)	(4,496)
Financing Activities:
Net (decrease) increase in time deposits	(33,466)	(11,255)	6,673
Net increase (decrease) in all other deposits	91,391	12,767	(11,209)
Net increase (decrease) in securities sold under repurchase agreements	2,311	20	(1,760)
Net (decrease) increase in other short-term borrowings	(154)	(2,253)	1,948
Net increase in short-term borrowings under money market liquidity facility	3,302	0	0
Proceeds from issuance of long-term debt, net of issuance costs	2,489	1,495	995
Payments for long-term debt and obligations under finance leases	(1,724)	(402)	(1,461)
Payments for redemption of preferred stock	(500)	(750)	0
Proceeds from issuance of preferred stock, net of issuance costs	0	0	495
Proceeds from issuance of common stock, net of issuance costs	0	0	1,150
Repurchases of common stock	(515)	(1,585)	(350)
Repurchases of common stock for employee tax withholding	(78)	(81)	(124)
Payments for cash dividends	(889)	(930)	(828)
Net cash provided by (used in) financing activities	62,167	(2,974)	(4,471)
Net increase	165	90	1,208
Cash and due from banks at beginning of period	3,302	3,212	2,004
Cash and due from banks at end of period	3,467	3,302	3,212
Supplemental disclosure:
Interest paid	375	1,382	981
Income taxes paid, net	$ 403	$ 510	$ 549