REGULATORY MATTERS - Schedule of Capital Ratios (Details) $ in Millions	Dec. 31, 2025 USD ($)	Dec. 31, 2024 USD ($)
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Total capital, actual amount	$ 4,971	$ 4,635
Tier 1 capital, actual amount	4,317	3,971
Common equity tier 1, actual amount	4,317	3,971
Leverage, actual amount	4,317	3,971
Risk weighted assets, actual amount	$ 37,991	$ 37,546
Total capital, actual ratio	0.1308	0.1235
Total capital, tier 1 capital, actual ratio	0.1136	0.1058
Common equity tier 1, actual ratio	0.1136	0.1058
Leverage, actual ratio	0.0911	0.0875
Total capital, well-capitalized requirements amount	$ 3,799	$ 3,755
Tier 1 capital, well-capitalized requirements amount	$ 2,279	$ 2,253
Total capital, well-capitalized requirements ratio	0.1000	0.1000
Tier 1 capital, well-capitalized requirements ratio	0.0600	0.0600
Total capital, minimum capital requirements plus capital conservation buffer amount	$ 3,989	$ 3,942
Tier 1 capital, minimum capital requirements plus capital conservation buffer amount	3,229	3,191
Common equity tier 1, minimum capital requirements plus capital conservation buffer amount	2,659	2,628
Leverage, minimum capital requirements plus capital conservation buffer amount	$ 1,896	$ 1,816
Total capital, minimum capital requirements plus capital conservation buffer ratio	0.1050	0.1050
Tier 1 capital, minimum capital requirements plus capital conservation buffer ratio	0.0850	0.0850
Common equity tier 1, minimum capital requirements plus capital conservation buffer ratio	0.0700	0.0700
Leverage, minimum capital requirements plus capital conservation buffer ratio	0.0400	0.0400
FNBPA
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Total capital, actual amount	$ 5,188	$ 4,794
Tier 1 capital, actual amount	4,371	3,962
Common equity tier 1, actual amount	4,291	3,882
Leverage, actual amount	4,371	3,962
Risk weighted assets, actual amount	$ 37,743	$ 37,280
Total capital, actual ratio	0.1375	0.1286
Total capital, tier 1 capital, actual ratio	0.1158	0.1063
Common equity tier 1, actual ratio	0.1137	0.1041
Leverage, actual ratio	0.0927	0.0878
Total capital, well-capitalized requirements amount	$ 3,774	$ 3,728
Tier 1 capital, well-capitalized requirements amount	3,019	2,982
Common equity tier 1, well-capitalized requirements amount	2,453	2,423
Leverage, well-capitalized requirements amount	$ 2,357	$ 2,257
Total capital, well-capitalized requirements ratio	0.1000	0.1000
Tier 1 capital, well-capitalized requirements ratio	0.0800	0.0800
Common equity tier 1, well-capitalized requirements ratio	0.0650	0.0650
Leverage, well-capitalized requirements ratio	0.0500	0.0500
Total capital, minimum capital requirements plus capital conservation buffer amount	$ 3,963	$ 3,914
Tier 1 capital, minimum capital requirements plus capital conservation buffer amount	3,208	3,169
Common equity tier 1, minimum capital requirements plus capital conservation buffer amount	2,642	2,610
Leverage, minimum capital requirements plus capital conservation buffer amount	$ 1,885	$ 1,806
Total capital, minimum capital requirements plus capital conservation buffer ratio	0.1050	0.1050
Tier 1 capital, minimum capital requirements plus capital conservation buffer ratio	0.0850	0.0850
Common equity tier 1, minimum capital requirements plus capital conservation buffer ratio	0.0700	0.0700
Leverage, minimum capital requirements plus capital conservation buffer ratio	0.0400	0.0400

Banking Regulation, Tier 1 Risk-Based Capital, Capital Adequacy With Buffer, Minimum

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The common equity tier one capital ratio (common equity tier one capital divided by risk weighted assets) required to be categorized as "well capitalized" under the regulatory framework for prompt corrective action.

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Amount of minimum total risk-based capital required for capital adequacy as defined by regulatory framework.

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Amount of Common Equity Tier 1 risk-based capital as defined by regulatory framework.

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
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