Consolidated Statements of Stockholders' Equity (Unaudited) - USD ($) $ in Thousands	Total	Common stock	Additional paid-in capital	Retained earnings	Accumulated Other Comprehensive Income (Loss)	Unrealized investment gain	Currency Translation Adjustments	Treasury stock	Noncontrolling interest
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Cumulative effect adjustment resulting from changes in accounting principles		$ 105,803	$ 981,104	$ 9,015,135	$ (281,955)	$ 90,900	$ (372,855)	$ (3,167,076)	$ 14,719
Beginning of period at Dec. 31, 2021		105,803	981,104	9,015,135	(281,955)	90,900	(372,855)	(3,167,076)	14,719
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Restricted stock units issued			(2,370)
Restricted stock units expensed			22,359
Net income before noncontrolling interests	$ 772,496			769,960					2,536
Dividends ($0.11, $0.60, $0.71 and $0.69 per share, respectively)				(182,147)
Change in unrealized (losses) gains on securities without an allowance for expected credit losses	(760,553)					(743,969)
Change in unrealized gains (losses) on securities with an allowance for expected credit losses						(16,585)
Net change in period	12,879						12,879
Stock exercised/vested								1,347
Stock repurchased								0
Other	0
Contributions (distributions)									5,134
Other comprehensive loss, net of tax	$ (747,674)				(747,674)		12,879		(1)
End of period at Jun. 30, 2022			1,001,093	9,602,948	(1,029,630)	(669,654)	(359,976)	(3,165,729)	22,388
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Common stock dividends, per share, cash paid (in dollars per share)	$ 0.69
Cumulative effect adjustment resulting from changes in accounting principles		105,803	992,012	9,582,790	(649,229)	(332,646)	(316,583)	(3,166,873)	23,296
Beginning of period at Mar. 31, 2022		105,803	992,012	9,582,790	(649,229)	(332,646)	(316,583)	(3,166,873)	23,296
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Restricted stock units issued			(1,840)
Restricted stock units expensed			10,921
Net income before noncontrolling interests	$ 179,467			179,322					145
Dividends ($0.11, $0.60, $0.71 and $0.69 per share, respectively)				(159,164)
Change in unrealized (losses) gains on securities without an allowance for expected credit losses	(337,008)					(320,130)
Change in unrealized gains (losses) on securities with an allowance for expected credit losses						(16,878)
Net change in period	(43,393)						(43,393)
Stock exercised/vested								1,144
Stock repurchased								0
Other	0
Contributions (distributions)									(1,053)
Other comprehensive loss, net of tax	$ (380,401)				(380,401)		(43,393)		0
End of period at Jun. 30, 2022			1,001,093	9,602,948	(1,029,630)	(669,654)	(359,976)	(3,165,729)	22,388
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Common stock dividends, per share, cash paid (in dollars per share)	$ 0.60
Cumulative effect adjustment resulting from changes in accounting principles			1,001,093	9,602,948	(1,029,630)	(669,654)	(359,976)	(3,165,729)	22,388
Cumulative effect adjustment resulting from changes in accounting principles	$ 6,768,161	105,803	997,534	10,161,005	(1,264,581)	(892,905)	(371,676)	(3,251,429)	19,829
Beginning of period at Dec. 31, 2022	6,768,161	105,803	997,534	10,161,005	(1,264,581)	(892,905)	(371,676)	(3,251,429)	19,829
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Restricted stock units issued			(2)
Restricted stock units expensed			23,286
Net income before noncontrolling interests	651,453			650,434					1,019
Dividends ($0.11, $0.60, $0.71 and $0.69 per share, respectively)				(186,921)
Change in unrealized (losses) gains on securities without an allowance for expected credit losses	67,515					60,364
Change in unrealized gains (losses) on securities with an allowance for expected credit losses						7,150
Net change in period	15,394						15,394
Stock exercised/vested								992
Stock repurchased								(427,619)
Other	(4,225)
Contributions (distributions)									320
Other comprehensive loss, net of tax	82,909				82,909		15,394		(1)
End of period at Jun. 30, 2023	$ 6,908,352		1,020,818	10,624,518	(1,181,673)	(825,391)	(356,282)	(3,682,281)	21,167
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Common stock dividends, per share, cash paid (in dollars per share)	$ 0.71
Cumulative effect adjustment resulting from changes in accounting principles		105,803	1,008,128	10,296,539	(1,078,917)	(712,107)	(366,810)	(3,387,538)	21,608
Beginning of period at Mar. 31, 2023		$ 105,803	1,008,128	10,296,539	(1,078,917)	(712,107)	(366,810)	(3,387,538)	21,608
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Restricted stock units issued			1,198
Restricted stock units expensed			11,492
Net income before noncontrolling interests	$ 355,724			356,308					(584)
Dividends ($0.11, $0.60, $0.71 and $0.69 per share, respectively)				(28,329)
Change in unrealized (losses) gains on securities without an allowance for expected credit losses	(113,284)					(116,978)
Change in unrealized gains (losses) on securities with an allowance for expected credit losses						3,694
Net change in period	10,528						10,528
Stock exercised/vested								597
Stock repurchased								(292,467)
Other	(2,873)
Contributions (distributions)									143
Other comprehensive loss, net of tax	(102,756)				(102,756)		10,528		0
End of period at Jun. 30, 2023	$ 6,908,352		1,020,818	10,624,518	(1,181,673)	(825,391)	(356,282)	(3,682,281)	21,167
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Common stock dividends, per share, cash paid (in dollars per share)	$ 0.11
Cumulative effect adjustment resulting from changes in accounting principles	$ 6,908,352		$ 1,020,818	$ 10,624,518	$ (1,181,673)	$ (825,391)	$ (356,282)	$ (3,682,281)	$ 21,167