CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (LOSS) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Statement of Comprehensive Income [Abstract]
Net income, before-tax amount	$ 227,596	$ 124,194	$ 366,550	$ 605,810
Net income, tax	(46,912)	(27,729)	(76,476)	(133,242)
Net income	180,684	96,465	290,074	472,568
Before-tax Amount
Net unamortized unrealized holding (losses) gains on available for sale investment securities transferred to held to maturity	0	0	(708,549)	0
Reclassification adjustment for the change in unamortized holding (losses) gains on held to maturity investment securities	19,834	0	40,472	0
Net change	19,834	0	(668,077)	0
Income Tax
Net unamortized unrealized holding (losses) gains on available for sale investment securities transferred to held to maturity	0	0	171,115	0
Reclassification adjustment for the change in unamortized holding (losses) gains on held to maturity investment securities	(4,790)	0	(9,774)	0
Net change	(4,790)	0	161,341	0
Net of Tax Amount
Net unamortized unrealized holding (losses) gains on available for sale investment securities transferred to held to maturity	0	0	(537,434)	0
Reclassification adjustment for the change in unamortized holding (losses) gains on held to maturity investment securities	15,044	0	30,698	0
Net change	15,044	0	(506,736)	0
Before-tax Amount
Net unrealized gains (losses) arising during the period	255,064	(384,866)	773,230	(341,310)
Reclassification adjustment for realized (gains) losses included in net income	0	0	256,660	(1,030)
Net change	255,064	(384,866)	1,029,890	(342,340)
Income Tax
Net unrealized gains (losses) arising during the period	(61,598)	93,676	(186,735)	83,075
Reclassification adjustment for realized (gains) losses included in net income	0	0	(61,983)	251
Net change	(61,598)	93,676	(248,718)	83,326
Net of Tax Amount
Net unrealized gains (losses) arising during the period	193,466	(291,190)	586,495	(258,235)
Reclassification adjustment for realized (gains) losses included in net income	0	0	194,677	(779)
Net change	193,466	(291,190)	781,172	(259,014)
Before-tax Amount
Net unrealized gains (losses) arising during the period	52,985	(39,096)	(22,345)	(102,218)
Reclassification adjustment for realized (gains) losses included in net income	36,768	48,296	113,118	130,935
Net change	89,753	9,200	90,773	28,717
Income Tax
Net unrealized gains (losses) arising during the period	(12,796)	9,516	5,396	24,880
Reclassification adjustment for realized (gains) losses included in net income	(8,879)	(11,755)	(27,318)	(31,870)
Net change	(21,675)	(2,239)	(21,922)	(6,990)
Net of Tax Amount
Net unrealized gains (losses) arising during the period	40,189	(29,580)	(16,949)	(77,338)
Reclassification adjustment for realized (gains) losses included in net income	27,889	36,541	85,800	99,065
Net change	68,078	6,961	68,851	21,727
Total other comprehensive income (loss)	364,651	(375,666)	452,586	(313,623)
Other comprehensive income (loss), tax	(88,063)	91,437	(109,299)	76,336
Total other comprehensive income (loss), net of tax amount	276,588	(284,229)	343,287	(237,287)
Comprehensive income (loss)	457,272	(187,764)	633,361	235,281
Less: comprehensive income (loss) attributable to noncontrolling interest	(871)	(630)	(1,960)	(796)
Comprehensive income (loss) attributable to Synovus Financial Corp.	$ 458,143	$ (187,134)	$ 635,321	$ 236,077