Consolidated Statement of Cash Flows - USD ($) $ in Millions	3 Months Ended		12 Months Ended
	Mar. 31, 2020	Mar. 31, 2019	Dec. 31, 2019
Operating Activities:
Net income	$ 634	$ 508
Adjustments to reconcile net income to net cash provided by operating activities:
Deferred income tax expense (benefit)	8	(35)
Amortization of other intangible assets	58	60	$ 236
Other non-cash adjustments for depreciation, amortization and accretion, net	274	244
Losses (gains) related to investment securities, net	(2)	1
Change in trading account assets, net	42	4
Change in accrued interest and fees receivable, net	(43)	(74)
Change in collateral deposits, net	2,685	(1,527)
Change in unrealized losses (gains) on foreign exchange derivatives, net	(3,090)	(63)
Change in other assets, net	(891)	(816)
Change in accrued expenses and other liabilities, net	4,179	976
Other, net	185	143
Net cash provided by operating activities	4,039	(579)
Investing Activities:
Net decrease (increase) in interest-bearing deposits with banks	(78,770)	19,176
Net decrease (increase) in securities purchased under resale agreements	450	3,157
Proceeds from sales of available-for-sale securities	1,657	152
Proceeds from maturities of available-for-sale securities	4,219	3,959
Purchases of available-for-sale securities	(8,935)	(7,408)
Purchases of held-to-maturity securities under the MMLF program	(26,061)	0
Proceeds from maturities of held-to-maturity securities under the MMLF program	451	0
Proceeds from maturities of held-to-maturity securities	2,695	2,606
Purchases of held-to-maturity securities	(2,141)	(2,348)
Net (increase) in loans	(6,071)
Net (increase) in loans		2,409
Business acquisitions, net of cash acquired	0	(54)
Purchases of equity investments and other long-term assets	(794)	(71)
Purchases of premises and equipment, net	(114)	(171)
Other, net	641	264
Net cash (used in) provided by investing activities	(112,773)	21,671
Financing Activities:
Net (decrease) increase in time deposits	18,635	(5,876)
Net increase (decrease) in all other deposits	56,596	(12,013)
Net increase in short-term borrowings under money market liquidity facility	25,665	0
Net (decrease) increase in other short-term borrowings	8,267
Net (decrease) increase in other short-term borrowings		(1,807)
Proceeds from issuance of long-term debt, net of issuance costs	2,497	0
Payments for long-term debt and obligations under finance leases	(8)	(31)
Payments for redemption of preferred stock	(500)	0
Repurchases of common stock	(515)	(300)
Repurchases of common stock for employee tax withholding	(43)	(43)
Payments for cash dividends	(230)	(234)
Net cash (used in) financing activities	110,364	(20,304)
Net increase	1,630	788
Cash and due from banks at beginning of period	3,302	3,212	3,212
Cash and due from banks at end of period	$ 4,932	$ 4,000	$ 3,302