Parent Company Financial Statements - Condensed Statement of Cash Flows (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Cash flows from operating activities
Net income	$ 1,991,663	$ 1,858,746	$ 1,353,152
Adjustments to reconcile net income to net cash provided by operating activities
Provision for deferred income taxes	(29,987)	87,159	(31,291)
Net cash provided by operating activities	4,573,740	2,714,959	789,187
Cash flows from investing activities
Other, net	(619,028)	(510,302)	67,411
Cash flows from financing activities
Proceeds from long-term borrowings	998,540	9,500
Purchases of treasury stock	(1,800,000)		(373,750)
Dividends paid — common	(784,089)	(580,260)	(568,112)
Dividends paid — preferred	(96,927)	(68,200)	(68,256)
Proceeds from issuance of Series I preferred stock		495,000
Other, net	(13,177)	(26,710)	(11,413)
Net increase (decrease) in cash, cash equivalents and restricted cash	182,667	(215,166)	116,438
Supplemental disclosure of cash flow information
Interest received during the year	6,134,684	3,976,804	4,135,990
Income taxes received during the year	487,618	314,295	275,558
Parent Company [Member]
Cash flows from operating activities
Net income	1,991,663	1,858,746	1,353,152
Adjustments to reconcile net income to net cash provided by operating activities
Equity in undistributed income of subsidiaries	448,340	(854,643)	(650,246)
Provision for deferred income taxes	7,487	10,356	1,079
Net change in accrued income and expense	7,742	(23,047)	(24,206)
Net cash provided by operating activities	2,455,232	991,412	679,779
Cash flows from investing activities
Net investment in consolidated subsidiaries	53,958	(199,000)	125,654
Acquisition, net of cash consideration	537,978
Other, net	24,401	(2,777)	50,396
Net cash provided (used) by investing activities	616,337	(201,777)	176,050
Cash flows from financing activities
Repayment of short-term borrowings assumed in acquisition	(500,000)
Proceeds from long-term borrowings	499,250
Purchases of treasury stock	(1,800,000)		(373,750)
Dividends paid — common	(784,089)	(580,260)	(568,112)
Dividends paid — preferred	(96,927)	(68,200)	(68,256)
Other, net	1,972	(7,551)	(5,992)
Net cash used by financing activities	(2,679,794)	(161,011)	(1,016,110)
Net increase (decrease) in cash, cash equivalents and restricted cash	391,775	628,624	(160,281)
Cash and cash equivalents at beginning of year	1,428,693	800,069	960,350
Cash and cash equivalents at end of year	1,820,468	1,428,693	800,069
Supplemental disclosure of cash flow information
Interest received during the year	1,332	1,165	1,493
Interest paid during the year	49,419	20,457	30,913
Income taxes received during the year	$ 28,153	53,067	$ 11,528
Parent Company [Member] | Series I Preferred Stock [Member]
Cash flows from financing activities
Proceeds from issuance of Series I preferred stock		$ 495,000