XML 73 R43.htm IDEA: XBRL DOCUMENT v3.25.0.1

Investments (Tables)

12 Months Ended

Dec. 31, 2024

Investments [Abstract]

Schedule of Unrealized Gains (Losses) On Investments

Net unrealized gains and losses on investments included in "Other comprehensive income (loss)" ("OCI") in the Consolidated Statements of Stockholders' Equity by asset class were as follows for the years ended December 31, 2024, 2023, and 2022:

($ in thousands)						2024						2023						2022
AFS securities:
Fixed income securities						$	(316,796)					(353,288)						(527,926)
Total AFS securities						(316,796)						(353,288)						(527,926)
Short-term securities						8						35						35
Total net unrealized gains (losses)						(316,788)						(353,253)						(527,891)
Deferred income tax						66,526						74,184						110,857
Net unrealized gains (losses), net of deferred income tax						(250,262)						(279,069)						(417,034)
Increase (decrease) in net unrealized gains (losses) in OCI, net of deferred income tax						$	28,807					137,965						(597,915)

Schedule of Available-for-Sale Securities

Information regarding our AFS securities as of December 31, 2024 and December 31, 2023 were as follows:

December 31, 2024
						Cost/
						Amortized						Allowance for						Unrealized						Unrealized						Fair
($ in thousands)						Cost						Credit Losses						Gains						Losses						Value
AFS fixed income securities:
U.S. government and government agencies						$	139,906					—						2						(19,753)						120,155
Foreign government						10,656						(21)						—						(1,333)						9,302
Obligations of states and political subdivisions						483,609						(570)						550						(32,359)						451,230
Corporate securities						3,181,046						(14,924)						25,259						(123,201)						3,068,180
CLO and other ABS						2,065,611						(4,889)						22,116						(49,689)						2,033,149
RMBS						1,812,744						(11,544)						3,880						(112,722)						1,692,358
CMBS						782,506						—						1,478						(31,024)						752,960
Total AFS fixed income securities						$	8,476,078					(31,948)						53,285						(370,081)						8,127,334

December 31, 2023
						Cost/
						Amortized						Allowance for						Unrealized						Unrealized						Fair
($ in thousands)						Cost						Credit Losses						Gains						Losses						Value
AFS fixed income securities:
U.S. government and government agencies						$	223,157					—						139						(18,261)						205,035
Foreign government						11,140						(35)						—						(1,302)						9,803
Obligations of states and political subdivisions						612,938						(669)						2,623						(28,927)						585,965
Corporate securities						2,834,048						(12,999)						28,078						(137,888)						2,711,239
CLO and other ABS						1,911,831						(2,854)						11,855						(86,005)						1,834,827
RMBS						1,568,960						(11,649)						6,023						(85,851)						1,477,483
CMBS						718,623						(6)						1,358						(45,130)						674,845
Total AFS fixed income securities						$	7,880,697					$	(28,212)					50,076						(403,364)						7,499,197

Schedule of Debt Securities, Available-for-Sale, Allowance for Credit Loss

The following tables provide a roll forward of the ACL on our AFS fixed income securities for the years indicated:

2024			Beginning Balance						Current Provision for Securities without Prior Allowance						Initial Allowance for Purchased Credit Deteriorated Assets with Credit Deterioration						Increase (Decrease) on Securities with Prior Allowance, excluding intent (or Requirements) to Sell Securities						Reductions for Securities Sold						Reductions for Securities Identified as Intent (or Requirement) to Sell during the Period						Ending Balance
($ in thousands)
Foreign government			$	35					—						—						(7)						(7)						—						21
Obligations of states and political subdivisions			669						222						—						(275)						(46)						—						570
Corporate securities			12,999						4,952						—						(1,861)						(1,157)						(9)						14,924
CLO and other ABS			2,854						1,376						—						846						(187)						—						4,889
RMBS			11,649						11						—						370						(486)						—						11,544
CMBS			6						—						—						(6)						—						—						—
Total AFS fixed income securities			$	28,212					6,561						—						(933)						(1,883)						(9)						31,948

2023			Beginning Balance						Current Provisions for Securities without Prior Allowance						Initial Allowance for Purchased Credit Deteriorated Assets with Credit Deterioration						Increase (Decrease) on Securities with Prior Allowance, excluding intent (or Requirements) to Sell Securities						Reductions for Securities Sold						Reductions for Securities Identified as Intent (or Requirement) to Sell during the Period						Ending Balance
($ in thousands)
Foreign government			$	284					—						—						(249)						—						—						35
Obligations of states and political subdivisions			1,024						48						—						(281)						(122)						—						669
Corporate securities			30,330						3,457						—						(16,879)						(3,638)						(271)						12,999
CLO and other ABS			2,375						619						—						(116)						(24)						—						2,854
RMBS			11,597						17						—						447						(412)						—						11,649
CMBS			111						1						—						38						(144)						—						6
Total AFS fixed income securities			$	45,721					4,142						—						(17,040)						(4,340)						(271)						28,212

Schedule of Quantitative Information about Unrealized Losses on AFS

Quantitative information about unrealized losses on our AFS portfolio follows:

December 31, 2024						Less than 12 months												12 months or longer												Total
($ in thousands)						Fair  Value						Unrealized Losses						Fair Value						Unrealized Losses						Fair Value						Unrealized Losses
AFS fixed income securities:
U.S. government and government agencies						$	14,708					(70)						105,326						(19,683)						120,034						(19,753)
Foreign government						—						—						9,302						(1,333)						9,302						(1,333)
Obligations of states and political subdivisions						153,996						(3,539)						247,735						(28,820)						401,731						(32,359)
Corporate securities						684,999						(11,699)						1,083,392						(111,502)						1,768,391						(123,201)
CLO and other ABS						349,786						(6,296)						601,057						(43,393)						950,843						(49,689)
RMBS						714,061						(21,206)						677,574						(91,516)						1,391,635						(112,722)
CMBS						184,394						(2,870)						417,472						(28,154)						601,866						(31,024)
Total AFS fixed income securities						$	2,101,944					(45,680)						3,141,858						(324,401)						5,243,802						(370,081)

December 31, 2023						Less than 12 months												12 months or longer												Total
($ in thousands)						Fair  Value						Unrealized Losses						Fair Value						Unrealized Losses						Fair Value						Unrealized Losses
AFS fixed income securities:
U.S. government and government agencies						$	77,698					(188)						108,578						(18,073)						186,276						(18,261)
Foreign government						1,552						(87)						8,251						(1,215)						9,803						(1,302)
Obligations of states and political subdivisions						137,031						(962)						290,964						(27,965)						427,995						(28,927)
Corporate securities						263,423						(6,369)						1,439,422						(131,519)						1,702,845						(137,888)
CLO and other ABS						278,940						(7,120)						984,175						(78,885)						1,263,115						(86,005)
RMBS						351,976						(4,765)						757,914						(81,086)						1,109,890						(85,851)
CMBS						130,189						(2,995)						471,256						(42,135)						601,445						(45,130)
Total AFS fixed income securities						$	1,240,809					(22,486)						4,060,560						(380,878)						5,301,369						(403,364)

Schedule of Fixed Maturity Securities by Contractual Maturities

AFS and held-to-maturity ("HTM") fixed income securities at December 31, 2024, by contractual maturity are shown below. The maturities of RMBS, CMBS, CLO and other ABS securities were calculated using each security's estimated average life. Expected maturities may differ from contractual maturities because issuers may have the right to call or prepay obligations with or without call or prepayment penalties.

						AFS						HTM
($ in thousands)						Fair Value						Carrying Value						Fair Value
Due in one year or less						$	593,487					1,152						1,176
Due after one year through five years						3,556,760						15,767						15,461
Due after five years through 10 years						3,024,602						8,456						8,098
Due after 10 years						952,485						—						—
Total fixed income securities						$	8,127,334					25,375						24,735

Schedule of Alternative Investment Portfolio by Strategy and Remaining Commitment Amount and Maximum Exposure to Loss Associated with Each Strategy

The following table summarizes our alternative investment portfolio by strategy:

						December 31, 2024																		December 31, 2023
($ in thousands)						Carrying Value						Remaining Commitment						Maximum Exposure to Loss						Carrying Value						Remaining Commitment						Maximum Exposure to Loss
Alternative investments
Private equity						$	346,020					182,355						528,375						301,759						131,885						433,644
Private credit						52,100						99,185						151,285						54,500						89,401						143,901
Real assets						42,776						38,950						81,726						39,520						33,040						72,560
Total alternative investments						$	440,896					320,490						761,386						395,779						254,326						650,105

Schedule of Aggregated Summarized Balance Sheet Financial Information for Partnerships in Alternative Investment Portfolio

The following tables show gross summarized financial information for our alternative investments portfolio, including the portion we do not own. As the majority of these investments report results to us on a one quarter lag, the summarized financial statement information is as of, and for the 12-month period ended, September 30: 

Balance Sheet Information
December 31,
($ in millions)						2024						2023
Investments						$	165,301					142,411
Total assets						173,694						146,844
Total liabilities						26,713						15,854
Total partners’ capital						146,981						130,990

Schedule of Aggregated Summarized Income Statement Financial Information for Partnerships in Alternative Investment Portfolio

Income Statement Information
($ in millions)						2024						2023						2022
Net investment income (loss)						$	186					178						765
Realized gains						7,099						5,845						12,590
Net change in unrealized appreciation (depreciation)						9,745						5,810						(5,215)
Net income						$	17,030					11,833						8,140
Alternative investment income included in "Net investment income earned" on our Consolidated Statements of Income						37.1						26.8						23.0

Schedule of Securities Pledged as Collateral

The following table summarizes the market value of these securities at December 31, 2024:

($ in millions)						FHLBI Collateral						FHLBNY Collateral						Regulatory Deposits						Total
U.S. government and government agencies						$	—					—						21.4						21.4
Obligations of states and political subdivisions						—						—						3.0						3.0
RMBS						63.6						21.7						—						85.3
CMBS						1.5						8.1						—						9.6
Total pledged as collateral						$	65.1					29.8						24.4						119.3

Schedule of Pre-Tax Net Investment Income Earned

The components of pre-tax net investment income earned were as follows:

($ in thousands)						2024						2023						2022
Fixed income securities						$	389,198					345,886						259,918
CMLs						12,448						9,336						5,555
Equity securities						18,295						9,395						13,554
Short-term investments						20,274						14,818						3,997
Alternative investments						37,053						26,777						23,003
Other investments						864						650						258
Investment expenses						(21,081)						(18,212)						(18,130)
Net investment income earned						$	457,051					388,650						288,155

Schedule of Realized and Unrealized Gains (Losses) on Securities

The following table summarizes net realized and unrealized investment gains and losses for the periods indicated:

($ in thousands)						2024						2023						2022
Gross gains on sales						$	12,839					5,896						28,419
Gross losses on sales						(6,563)						(30,760)						(60,055)
Net realized gains (losses) on disposals						6,276						(24,864)						(31,636)
Net unrealized gains (losses) on equity securities						(1,964)						9,510						(32,127)
Net credit loss benefit (expense) on fixed income securities, AFS						(5,628)						12,898						(39,169)
Net credit loss benefit (expense) on fixed income securities, HTM						—						—						63
Net credit loss benefit (expense) on CMLs						217						(175)						(116)
Losses on securities for which we have the intent to sell						(1,248)						(921)						(11,823)
Other realized gains (losses)						(602)						—						—
Net realized and unrealized investment gains (losses)						$	(2,949)					(3,552)						(114,808)

Schedule of Unrealized Gain (Loss) on Equity Securities

Net unrealized gains and losses recognized in income on equity securities, as reflected in the table above, included the following:

($ in thousands)						2024						2023						2022
Unrealized gains (losses) recognized in income on equity securities:
On securities remaining in our portfolio at end of period						$	(66)					3,593						(10,454)
On securities sold in period						(1,898)						5,917						(21,673)
Total unrealized gains (losses) recognized in income on equity securities						$	(1,964)					9,510						(32,127)

X

- Definition

Schedule of aggregate summarized balance sheet information for alternative investments accounted for by the equity method.

+ References

No definition available.

+ Details

Name:	sigi_ScheduleOfAggregatedSummarizedBalanceSheetFinancialInformationForPartnerhipsInOurAlternativeInvestmentPortfolioTableTextBlock
Namespace Prefix:	sigi_
Data Type:	dtr-types1:textBlockItemType
Balance Type:	na
Period Type:	duration

X

- Definition

Schedule of aggregate summarized income statement information for alternative investments accounted for by the equity method.

+ References

No definition available.

+ Details

Name:	sigi_ScheduleOfAggregatedSummarizedIncomeStatementFinancialInformationForPartnerhipsInOurAlternativeInvestmentPortfolioTableTextBlock
Namespace Prefix:	sigi_
Data Type:	dtr-types1:textBlockItemType
Balance Type:	na
Period Type:	duration

X

- Definition

Represents disclosure of information regarding the alternative investment portfolio, including carrying value, remaining commitments, and maximum exposure to loss broken out by strategy.

+ References

No definition available.

+ Details

Name:	sigi_ScheduleOfAlternativeInvestmentPortfolioByStrategyRemainingCommitmentAmountAndMaximumExposureToLossAssociatedWithEachStrategyTableTextBlock
Namespace Prefix:	sigi_
Data Type:	dtr-types1:textBlockItemType
Balance Type:	na
Period Type:	duration

X

- Definition

Tabular disclosure that provides unrealized gains or losses recognized in income on equity securities separated by: (i) securities that continue to be held; and (ii) securities that were sold.

+ References

No definition available.

+ Details

Name:	sigi_UnrealizedGainLossonSecuritiesTableTextBlock
Namespace Prefix:	sigi_
Data Type:	dtr-types1:textBlockItemType
Balance Type:	na
Period Type:	duration

X

- Definition

Tabular disclosure of allowance for credit loss on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 326
-SubTopic 30
-Name Accounting Standards Codification
-Section 50
-Paragraph 9
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479106/326-30-50-9

+ Details

Name:	us-gaap_DebtSecuritiesAvailableForSaleAllowanceForCreditLossTableTextBlock
Namespace Prefix:	us-gaap_
Data Type:	dtr-types:textBlockItemType
Balance Type:	na
Period Type:	duration

X

- Definition

Tabular disclosure of fair value of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), in unrealized loss position, without allowance for credit loss. Includes beneficial interest in securitized financial asset.

+ References

Reference 1: http://www.xbrl.org/2003/role/exampleRef
-Topic 326
-SubTopic 30
-Name Accounting Standards Codification
-Section 55
-Paragraph 8
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479081/326-30-55-8

Reference 2: http://fasb.org/us-gaap/role/ref/otherTransitionRef
-Topic 320
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 6
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481800/320-10-50-6

Reference 3: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 326
-SubTopic 30
-Name Accounting Standards Codification
-Section 50
-Paragraph 4
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479106/326-30-50-4

+ Details

Name:	us-gaap_DebtSecuritiesAvailableForSaleUnrealizedLossPositionFairValueTableTextBlock
Namespace Prefix:	us-gaap_
Data Type:	dtr-types:textBlockItemType
Balance Type:	na
Period Type:	duration

X

- Definition

Tabular disclosure of realized and unrealized gain (loss) on investment in security.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 220
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 2
-Subparagraph (SX 210.5-03(9)(a))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147483621/220-10-S99-2

Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 220
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 2
-Subparagraph (SX 210.5-03(7)(c))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147483621/220-10-S99-2

+ Details

Name:	us-gaap_GainLossOnInvestmentsTextBlock
Namespace Prefix:	us-gaap_
Data Type:	dtr-types:textBlockItemType
Balance Type:	na
Period Type:	duration

X

- Definition

Tabular disclosure of investment income, including, but not limited to, interest and dividend income and amortization of discount (premium) derived from debt and equity securities. Excludes realized and unrealized gain (loss) on investments.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Topic 220
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 2
-Subparagraph (SX 210.5-03(8))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147483621/220-10-S99-2

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Topic 220
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 2
-Subparagraph (SX 210.5-03(7)(a))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147483621/220-10-S99-2

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Topic 220
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 2
-Subparagraph (SX 210.5-03(7)(b))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147483621/220-10-S99-2

Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef
-Topic 220
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 2
-Subparagraph (SX 210.5-03(9))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147483621/220-10-S99-2

Reference 5: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 944
-SubTopic 220
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-04(2))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147477250/944-220-S99-1

+ Details

Name:	us-gaap_InvestmentIncomeTextBlock
Namespace Prefix:	us-gaap_
Data Type:	dtr-types:textBlockItemType
Balance Type:	na
Period Type:	duration

X

- References

No definition available.

+ Details

Name:	us-gaap_InvestmentsAbstract
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

X

- Definition

Tabular disclosure of maturities of an entity's investments as well as any other information pertinent to the investments.

+ References

No definition available.

+ Details

Name:	us-gaap_InvestmentsClassifiedByContractualMaturityDateTableTextBlock
Namespace Prefix:	us-gaap_
Data Type:	dtr-types:textBlockItemType
Balance Type:	na
Period Type:	duration

X

- Definition

Tabular disclosure of the reconciliation of available-for-sale securities from cost basis to fair value.

+ References

No definition available.

+ Details

Name:	us-gaap_ScheduleOfAvailableForSaleSecuritiesReconciliationTableTextBlock
Namespace Prefix:	us-gaap_
Data Type:	dtr-types:textBlockItemType
Balance Type:	na
Period Type:	duration

X

- Definition

Tabular disclosure of financial instruments held by the entity for its own account for trading or investment purposes that are carried at fair value and pledged to counterparties as collateral for financing transactions. Description may include equity, fixed income, debt or other securities.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 860
-SubTopic 30
-Name Accounting Standards Codification
-Section 45
-Paragraph 1
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481444/860-30-45-1

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Topic 860
-SubTopic 30
-Name Accounting Standards Codification
-Section 50
-Paragraph 1A
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481420/860-30-50-1A

+ Details

Name:	us-gaap_ScheduleOfFinancialInstrumentsOwnedAndPledgedAsCollateralTextBlock
Namespace Prefix:	us-gaap_
Data Type:	dtr-types:textBlockItemType
Balance Type:	na
Period Type:	duration

X

- Definition

Tabular disclosure of unrealized gains and losses on investments.

+ References

No definition available.

+ Details

Name:	us-gaap_UnrealizedGainLossOnInvestmentsTableTextBlock
Namespace Prefix:	us-gaap_
Data Type:	dtr-types:textBlockItemType
Balance Type:	na
Period Type:	duration