Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Cash flows from operating activities:
Net income before noncontrolling interests	$ 1,294,294	$ 1,184,717	$ 1,011,348
Adjustments to reconcile net income to net cash provided by operating activities:
Provision for credit losses	219,510	106,416	87,870
Gains on investment securities, net	(420,752)	(134,670)	(88,094)
Distributions of earnings from non-marketable and other equity securities	85,587	95,131	72,015
Depreciation and amortization	100,840	82,717	57,906
Amortization of premiums and discounts on investment securities, net	75,178	15,513	(28)
Amortization of share-based compensation	83,986	66,815	45,675
Amortization of deferred loan fees	(173,975)	(155,429)	(128,077)
Deferred income tax expense (benefit)	6,911	(3,072)	(21,061)
Excess tax benefit from exercise of stock options and vesting of restricted shares	(5,857)	(9,588)	(17,989)
Losses from the write-off of premises and equipment and right-of-use assets	30,170	5,219	7,278
Other losses	0	8,959	0
Changes in other assets and liabilities:
Accrued interest receivable and payable, net	(26,205)	(24,189)	(55,834)
Accounts receivable and payable, net	18,765	(17,019)	(23,020)
Income tax receivable and payable, net	97,607	(11,630)	(5,820)
Accrued compensation	190,983	(15,253)	56,874
Foreign exchange spot contracts, net	(20,790)	59,998	24,018
Proceeds from termination of interest rate swaps	227,500	0	0
Other, net	(287,905)	(74,240)	(54,039)
Net cash provided by operating activities	1,445,487	1,164,129	933,562
Cash flows from investing activities:
Purchases of available-for-sale securities	(23,207,791)	(9,872,095)	(668,264)
Proceeds from sales of available-for-sale securities	2,654,212	2,189,087	474,482
Proceeds from maturities and paydowns of available-for-sale securities	4,183,888	1,643,357	3,436,064
Purchases of held-to-maturity securities	(6,778,370)	(492,502)	(4,726,595)
Proceeds from maturities and paydowns of held-to-maturity securities	4,035,952	2,124,513	1,891,761
Purchases of non-marketable and other equity securities	(201,293)	(136,186)	(81,574)
Proceeds from sales and distributions of capital of non-marketable and other equity securities	148,224	113,526	95,025
Net increase in loans	(11,926,436)	(4,773,775)	(5,175,409)
Purchases of premises and equipment	(87,407)	(65,479)	(45,865)
Business acquisitions	(26,700)	(102,328)	0
Net cash used for investing activities	(31,205,721)	(9,371,882)	(4,800,375)
Cash flows from financing activities:
Net increase in deposits	40,224,000	12,428,907	5,074,825
Net increase (decrease) in short-term borrowings	3,123	(613,982)	(402,318)
Principal payments of long-term debt	0	(358,395)	0
Proceeds from issuance of 3.125% Senior Notes	495,024	0	0
(Distributions to noncontrolling interests), net of contributions from noncontrolling interests	(22,908)	(50,978)	(28,494)
Net proceeds from the issuance of preferred stock	0	340,138	0
Payment of preferred stock dividends	(17,151)	0	0
Common stock repurchase	(60,020)	(352,511)	(147,123)
Proceeds from issuance of common stock, ESPP and ESOP	31,146	24,818	18,387
Net cash provided by financing activities	40,653,214	11,417,997	4,515,277
Net increase in cash and cash equivalents	10,892,980	3,210,244	648,464
Cash and cash equivalents at beginning of period	6,781,783	3,571,539	2,923,075
Cash and cash equivalents at end of period	17,674,763	6,781,783	3,571,539
Cash paid during the period for:
Interest	83,746	217,961	75,601
Income taxes	299,175	422,346	376,425
Noncash items during the period:
Changes in unrealized gains and losses on available-for-sale securities, net of tax	393,305	139,934	(15,498)
Distributions of stock from investments	11,913	8,917	5,277
Retained Earnings
Cash flows from operating activities:
Net income before noncontrolling interests	1,208,368	1,136,856	973,840
Cash flows from financing activities:
Payment of preferred stock dividends	(17,151)
Equity warrant assets
Adjustments to reconcile net income to net cash provided by operating activities:
Changes in fair value of derivatives	(2,347)	2,240	(24,417)
Derivative
Adjustments to reconcile net income to net cash provided by operating activities:
Changes in fair value of derivatives	$ (48,013)	$ (18,506)	$ (11,043)