Consolidated Statements of Stockholders' Equity (Unaudited) - USD ($) $ in Thousands	Total	Common stock	Additional paid-in capital	Retained earnings	Unrealized investment losses:	Change in unrealized gains (losses) on securities without an allowance for expected credit losses	Change in unrealized gains (losses) on securities with an allowance for expected credit losses	Currency translation adjustments:	Accumulated Other Comprehensive Income (Loss)	Treasury stock	Noncontrolling interest
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Cumulative effect adjustment resulting from changes in accounting principles		$ 158,705	$ 964,789	$ 11,040,908	$ (586,354)			$ (339,484)	$ (925,838)	$ (3,783,133)	$ 13,806
Beginning of period at Dec. 31, 2023		158,705	964,789	11,040,908	(586,354)			(339,484)	(925,838)	(3,783,133)	13,806
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Restricted stock units issued			(3,145)
Restricted stock units expensed			25,248
Net income before noncontrolling interests	$ 813,920			814,380							(460)
Dividends ($0.59, $0.41, $0.67 and $0.49 per share, respectively)				(185,721)
Change in unrealized gains (losses) on securities without an allowance for expected credit losses	(83,460)					$ (76,763)
Change in unrealized gains (losses) on securities with an allowance for expected credit losses							$ (6,696)
Net change in period	(24,343)							(24,343)
Stock exercised/vested										1,324
Stock repurchased										(223,763)
Other	(2,170)
Distributions											(78)
Other comprehensive income (loss), net of tax	$ (107,803)				(83,460)			(24,343)	(107,803)		1
End of period at Jun. 30, 2024			986,892	11,669,567	(669,813)			(363,827)	(1,033,640)	(4,007,742)	13,269
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Common stock dividends, per share, cash paid (in dollars per share)	$ 0.49
Cumulative effect adjustment resulting from changes in accounting principles		158,705	977,573	11,455,158	(656,476)			(367,054)	(1,023,530)	(3,783,074)	13,680
Beginning of period at Mar. 31, 2024		158,705	977,573	11,455,158	(656,476)			(367,054)	(1,023,530)	(3,783,074)	13,680
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Restricted stock units issued			(2,950)
Restricted stock units expensed			12,269
Net income before noncontrolling interests	$ 371,885			371,909							(24)
Dividends ($0.59, $0.41, $0.67 and $0.49 per share, respectively)				(157,500)
Change in unrealized gains (losses) on securities without an allowance for expected credit losses	(13,338)					(5,654)
Change in unrealized gains (losses) on securities with an allowance for expected credit losses							(7,683)
Net change in period	3,227							3,227
Stock exercised/vested										1,265
Stock repurchased										(223,763)
Other	(2,170)
Distributions											(388)
Other comprehensive income (loss), net of tax	(10,111)				(13,338)			3,227	(10,111)		1
End of period at Jun. 30, 2024			986,892	11,669,567	(669,813)			(363,827)	(1,033,640)	(4,007,742)	13,269
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Cumulative effect adjustment resulting from changes in accounting principles			986,892	11,669,567	(669,813)			(363,827)	(1,033,640)	(4,007,742)	13,269
Cumulative effect adjustment resulting from changes in accounting principles	8,407,439	158,705	984,825	12,265,070	(517,170)			(417,099)	(934,269)	(4,079,220)	12,328
Beginning of period at Dec. 31, 2024	8,407,439	158,705	984,825	12,265,070	(517,170)			(417,099)	(934,269)	(4,079,220)	12,328
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Restricted stock units issued			(4,885)
Restricted stock units expensed			25,488
Net income before noncontrolling interests	818,058			818,860							(802)
Dividends ($0.59, $0.41, $0.67 and $0.49 per share, respectively)				(254,175)
Change in unrealized gains (losses) on securities without an allowance for expected credit losses	268,538					268,610
Change in unrealized gains (losses) on securities with an allowance for expected credit losses							(73)
Net change in period	93,348							93,348
Stock exercised/vested										1,836
Stock repurchased										(49,202)
Other	(381)
Distributions											(1,254)
Other comprehensive income (loss), net of tax	361,886				268,538			93,348	361,886		(1)
End of period at Jun. 30, 2025	$ 9,304,808		1,005,428	12,829,755	(248,633)			(323,751)	(572,384)	(4,126,967)	10,271
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Common stock dividends, per share, cash paid (in dollars per share)	$ 0.67
Cumulative effect adjustment resulting from changes in accounting principles		158,705	992,901	12,652,303	(368,898)			(393,169)	(762,067)	(4,127,803)	12,333
Beginning of period at Mar. 31, 2025		$ 158,705	992,901	12,652,303	(368,898)			(393,169)	(762,067)	(4,127,803)	12,333
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Restricted stock units issued			(538)
Restricted stock units expensed			13,065
Net income before noncontrolling interests	$ 400,708			401,288							(580)
Dividends ($0.59, $0.41, $0.67 and $0.49 per share, respectively)				(223,836)
Change in unrealized gains (losses) on securities without an allowance for expected credit losses	120,265					$ 119,787
Change in unrealized gains (losses) on securities with an allowance for expected credit losses							$ 478
Net change in period	69,418							69,418
Stock exercised/vested										786
Stock repurchased										0
Other	50
Distributions											(1,482)
Other comprehensive income (loss), net of tax	189,683				120,265			69,418	189,683		0
End of period at Jun. 30, 2025	9,304,808		1,005,428	12,829,755	(248,633)			(323,751)	(572,384)	(4,126,967)	10,271
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Cumulative effect adjustment resulting from changes in accounting principles	$ 9,304,808		$ 1,005,428	$ 12,829,755	$ (248,633)			$ (323,751)	$ (572,384)	$ (4,126,967)	$ 10,271