XML 117 R98.htm IDEA: XBRL DOCUMENT v3.25.0.1

STOCK-BASED COMPENSATION PLANS - Summary of Stock Options Outstanding (Details) $ / shares in Units, $ in Millions	12 Months Ended
	Dec. 31, 2024 USD ($) $ / shares shares
Share-Based Payment Arrangement, Option, Exercise Price Range, Beginning of Period [Abstract]
Share-Based Payment Arrangement, Option, Exercise Price Range, Shares Outstanding | shares	1,643,927
Share-Based Payment Arrangement, Option, Exercise Price Range, Outstanding, Weighted Average Exercise Price	$ 54.31
Share-Based Payment Arrangement, Option, Exercise Price Range, Outstanding, Weighted Average Remaining Contractual Term	5 years 6 months 18 days
Share-Based Payment Arrangement, Option, Exercise Price Range, Shares Exercisable | shares	1,047,708
Share-Based Payment Arrangement, Option, Exercise Price Range, Exercisable, Weighted Average Exercise Price	$ 54.98
Weighted-average remaining contractual term of outstanding stock options	5 years 6 months 18 days
Weighted-average remaining contractual term of outstanding and exercisable stock options	4 years 3 days
Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Outstanding, Intrinsic Value | $	$ 9.9
Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Exercisable, Intrinsic Value | $	$ 9.9
$0.00 - $26.00
Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Additional Disclosures [Abstract]
Share-Based Payment Arrangement, Option, Exercise Price Range, Lower Range Limit	$ 0
Share-Based Payment Arrangement, Option, Exercise Price Range, Upper Range Limit	$ 26
Share-Based Payment Arrangement, Option, Exercise Price Range, Beginning of Period [Abstract]
Share-Based Payment Arrangement, Option, Exercise Price Range, Shares Outstanding | shares	30,002
Share-Based Payment Arrangement, Option, Exercise Price Range, Outstanding, Weighted Average Exercise Price	$ 23.04
Share-Based Payment Arrangement, Option, Exercise Price Range, Outstanding, Weighted Average Remaining Contractual Term	2 years
Share-Based Payment Arrangement, Option, Exercise Price Range, Shares Exercisable | shares	30,002
Share-Based Payment Arrangement, Option, Exercise Price Range, Exercisable, Weighted Average Exercise Price	$ 23.04
$26.01 - $36.00
Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Additional Disclosures [Abstract]
Share-Based Payment Arrangement, Option, Exercise Price Range, Lower Range Limit	26.01
Share-Based Payment Arrangement, Option, Exercise Price Range, Upper Range Limit	$ 36
Share-Based Payment Arrangement, Option, Exercise Price Range, Beginning of Period [Abstract]
Share-Based Payment Arrangement, Option, Exercise Price Range, Shares Outstanding | shares	51,207
Share-Based Payment Arrangement, Option, Exercise Price Range, Outstanding, Weighted Average Exercise Price	$ 35.36
Share-Based Payment Arrangement, Option, Exercise Price Range, Outstanding, Weighted Average Remaining Contractual Term	2 months 15 days
Share-Based Payment Arrangement, Option, Exercise Price Range, Shares Exercisable | shares	51,207
Share-Based Payment Arrangement, Option, Exercise Price Range, Exercisable, Weighted Average Exercise Price	$ 35.36
$36.01 - $46.00
Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Additional Disclosures [Abstract]
Share-Based Payment Arrangement, Option, Exercise Price Range, Lower Range Limit	36.01
Share-Based Payment Arrangement, Option, Exercise Price Range, Upper Range Limit	$ 46
Share-Based Payment Arrangement, Option, Exercise Price Range, Beginning of Period [Abstract]
Share-Based Payment Arrangement, Option, Exercise Price Range, Shares Outstanding | shares	452,106
Share-Based Payment Arrangement, Option, Exercise Price Range, Outstanding, Weighted Average Exercise Price	$ 42.19
Share-Based Payment Arrangement, Option, Exercise Price Range, Outstanding, Weighted Average Remaining Contractual Term	6 years 6 months 3 days
Share-Based Payment Arrangement, Option, Exercise Price Range, Shares Exercisable | shares	159,712
Share-Based Payment Arrangement, Option, Exercise Price Range, Exercisable, Weighted Average Exercise Price	$ 38.37
$46.01 - $56.00
Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Additional Disclosures [Abstract]
Share-Based Payment Arrangement, Option, Exercise Price Range, Lower Range Limit	46.01
Share-Based Payment Arrangement, Option, Exercise Price Range, Upper Range Limit	$ 56
Share-Based Payment Arrangement, Option, Exercise Price Range, Beginning of Period [Abstract]
Share-Based Payment Arrangement, Option, Exercise Price Range, Shares Outstanding | shares	542,707
Share-Based Payment Arrangement, Option, Exercise Price Range, Outstanding, Weighted Average Exercise Price	$ 53.73
Share-Based Payment Arrangement, Option, Exercise Price Range, Outstanding, Weighted Average Remaining Contractual Term	5 years 10 months 24 days
Share-Based Payment Arrangement, Option, Exercise Price Range, Shares Exercisable | shares	354,494
Share-Based Payment Arrangement, Option, Exercise Price Range, Exercisable, Weighted Average Exercise Price	$ 53.73
$56.01 - $81.00
Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Additional Disclosures [Abstract]
Share-Based Payment Arrangement, Option, Exercise Price Range, Lower Range Limit	56.01
Share-Based Payment Arrangement, Option, Exercise Price Range, Upper Range Limit	$ 81
Share-Based Payment Arrangement, Option, Exercise Price Range, Beginning of Period [Abstract]
Share-Based Payment Arrangement, Option, Exercise Price Range, Shares Outstanding | shares	567,905
Share-Based Payment Arrangement, Option, Exercise Price Range, Outstanding, Weighted Average Exercise Price	$ 67.88
Share-Based Payment Arrangement, Option, Exercise Price Range, Outstanding, Weighted Average Remaining Contractual Term	5 years 1 month 13 days
Share-Based Payment Arrangement, Option, Exercise Price Range, Shares Exercisable | shares	452,293
Share-Based Payment Arrangement, Option, Exercise Price Range, Exercisable, Weighted Average Exercise Price	$ 66.15

X

- References

No definition available.

+ Details

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

X

- Definition

Amount by which the current fair value of the underlying stock exceeds the exercise price of options outstanding.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480429/718-10-50-2

+ Details

Name:	us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingIntrinsicValue
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

X

- References

No definition available.

+ Details

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

X

- Definition

The floor of a customized range of exercise prices for purposes of disclosing shares potentially issuable under outstanding stock option awards on all stock option plans and other required information pertaining to awards in the customized range.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (g)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480429/718-10-50-2

+ Details

Name:	us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeLowerRangeLimit
Namespace Prefix:	us-gaap_
Data Type:	dtr-types:perShareItemType
Balance Type:	na
Period Type:	duration

X

- Definition

The number of shares reserved for issuance pertaining to the outstanding exercisable stock options as of the balance sheet date in the customized range of exercise prices for which the market and performance vesting condition has been satisfied.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (c)(iii)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480429/718-10-50-2

+ Details

Name:	us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeNumberOfExercisableOptions
Namespace Prefix:	us-gaap_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	instant

X

- Definition

The number of shares reserved for issuance pertaining to the outstanding stock options as of the balance sheet date for all option plans in the customized range of exercise prices.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Topic 718
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (c)(1)(ii)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480429/718-10-50-2

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Topic 718
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (c)(1)(i)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480429/718-10-50-2

+ Details

Name:	us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeNumberOfOutstandingOptions
Namespace Prefix:	us-gaap_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	instant

X

- Definition

The ceiling of a customized range of exercise prices for purposes of disclosing shares potentially issuable under outstanding stock option awards on all stock option plans and other required information pertaining to awards in the customized range.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (g)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480429/718-10-50-2

+ Details

Name:	us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeUpperRangeLimit
Namespace Prefix:	us-gaap_
Data Type:	dtr-types:perShareItemType
Balance Type:	na
Period Type:	duration

X

- Definition

Amount of difference between fair value of the underlying shares reserved for issuance and exercise price of vested portions of options outstanding and currently exercisable.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480429/718-10-50-2

+ Details

Name:	us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsExercisableIntrinsicValue1
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

X

- Definition

Weighted average remaining contractual term for vested portions of options outstanding and currently exercisable or convertible, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480429/718-10-50-2

+ Details

Name:	us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsExercisableWeightedAverageRemainingContractualTerm1
Namespace Prefix:	us-gaap_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

X

- Definition

Weighted average remaining contractual term for option awards outstanding, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Topic 718
-SubTopic 10
-Subparagraph (e)(1)
-Name Accounting Standards Codification
-Paragraph 2
-Section 50
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480429/718-10-50-2

+ Details

Name:	us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsOutstandingWeightedAverageRemainingContractualTerm2
Namespace Prefix:	us-gaap_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

X

- Definition

Weighted average exercise price as of the balance sheet date for those equity-based payment arrangements exercisable and outstanding.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (c)(1)(iii)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480429/718-10-50-2

+ Details

Name:	us-gaap_SharebasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeExercisableOptionsWeightedAverageExercisePrice1
Namespace Prefix:	us-gaap_
Data Type:	dtr-types:perShareItemType
Balance Type:	na
Period Type:	instant

X

- Definition

The weighted average price as of the balance sheet date at which grantees could acquire the underlying shares with respect to all outstanding stock options which are in the customized range of exercise prices.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Topic 718
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (c)(1)(ii)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480429/718-10-50-2

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Topic 718
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (c)(1)(i)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480429/718-10-50-2

+ Details

Name:	us-gaap_SharebasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeOutstandingOptionsWeightedAverageExercisePriceBeginningBalance1
Namespace Prefix:	us-gaap_
Data Type:	dtr-types:perShareItemType
Balance Type:	na
Period Type:	instant

X

- Definition

Weighted average remaining contractual term of outstanding stock options, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Topic 718
-SubTopic 10
-Subparagraph (e)(1)
-Name Accounting Standards Codification
-Paragraph 2
-Section 50
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480429/718-10-50-2

+ Details

Name:	us-gaap_SharebasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeOutstandingOptionsWeightedAverageRemainingContractualTerm2
Namespace Prefix:	us-gaap_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

X

- Details

Name:	us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis=cbu_RangeOfExercisePriceMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis=cbu_RangeOfExercisePriceBMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis=cbu_RangeOfExercisePriceCMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis=cbu_RangeOfExercisePriceDMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis=cbu_RangeOfExercisePriceEMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: