v3.25.2
BUSINESS SEGMENTS - Schedule of Financial Information for Segments of FNB (Details) - USD ($)
$ in Millions
 3 Months Ended 6 Months Ended
Jun. 30, 2025
Jun. 30, 2024
Jun. 30, 2025
Jun. 30, 2024
Dec. 31, 2024
Segment Reporting Information [Line Items]          
Interest income $ 583.0 $ 557.0 $ 1,142.0 $ 1,100.0  
Interest expense 235.0 241.0 471.0 465.0  
Net Interest Income 348.0 316.0 671.0 635.0  
Provision for Credit Losses 26.0 20.0 43.1 34.1  
Non-interest income:          
Service charges 23.0 23.0 45.0 44.0  
Interchange and card transaction fees 14.0 13.0 26.0 26.0  
Trust services 11.0 12.0 24.0 23.0  
Insurance commissions and fees 5.0 6.0 11.0 13.0  
Securities commissions and fees 9.0 8.0 18.0 16.0  
Capital markets income 7.0 5.0 12.0 11.0  
Mortgage banking operations 6.0 7.0 13.0 15.0  
Other 16.0 14.0 30.0 28.0  
Total Non-Interest Income 91.0 88.0 179.0 176.0  
Non-interest expense:          
Salaries and employee benefits 130.0 121.0 265.0 250.0  
Other 117.0 106.0 228.0 214.0  
Total Non-Interest Expense 247.0 227.0 493.0 464.0  
Income taxes 36.0 34.0 67.0 68.0  
Net Income 130.0 123.0 247.0 245.0  
Total assets 49,725.0 47,715.0 49,725.0 47,715.0 $ 48,625.0
Total Loans and Leases 34,679.0 [1] 33,757.0 34,679.0 [1] 33,757.0 33,939.0 [1]
Total deposits 37,748.0 34,994.0 37,748.0 34,994.0 $ 37,107.0
Market value of assets under administration - FNBIA, FNTC and FNIS 14,425.0 13,520.0 14,425.0 13,520.0  
Operating Segments | Community Banking          
Segment Reporting Information [Line Items]          
Interest income 581.0 555.0 1,139.0 1,097.0  
Interest expense 221.0 233.0 442.0 451.0  
Net Interest Income 360.0 322.0 697.0 646.0  
Provision for Credit Losses 26.0 20.0 43.0 34.0  
Non-interest income:          
Service charges 23.0 23.0 45.0 44.0  
Interchange and card transaction fees 14.0 13.0 26.0 26.0  
Trust services 0.0 0.0 0.0 0.0  
Insurance commissions and fees 0.0 0.0 0.0 0.0  
Securities commissions and fees 0.0 0.0 0.0 0.0  
Capital markets income 6.0 5.0 10.0 10.0  
Mortgage banking operations 6.0 7.0 13.0 15.0  
Other 17.0 16.0 35.0 32.0  
Total Non-Interest Income 66.0 64.0 129.0 127.0  
Non-interest expense:          
Salaries and employee benefits 114.0 105.0 235.0 220.0  
Other 103.0 99.0 204.0 199.0  
Total Non-Interest Expense 217.0 204.0 439.0 419.0  
Income taxes 40.0 36.0 74.0 70.0  
Net Income 143.0 126.0 270.0 250.0  
Total assets 49,380.0 47,421.0 49,380.0 47,421.0  
Total Loans and Leases 34,634.0 33,716.0 34,634.0 33,716.0  
Total deposits 38,552.0 35,338.0 38,552.0 35,338.0  
Market value of assets under administration - FNBIA, FNTC and FNIS 0.0 0.0 0.0 0.0  
Operating Segments | Wealth Management          
Segment Reporting Information [Line Items]          
Interest income 0.0 0.0 0.0 0.0  
Interest expense 0.0 0.0 0.0 0.0  
Net Interest Income 0.0 0.0 0.0 0.0  
Provision for Credit Losses 0.0 0.0 0.0 0.0  
Non-interest income:          
Service charges 0.0 0.0 0.0 0.0  
Interchange and card transaction fees 0.0 0.0 0.0 0.0  
Trust services 11.0 12.0 24.0 23.0  
Insurance commissions and fees 0.0 0.0 0.0 0.0  
Securities commissions and fees 9.0 8.0 18.0 16.0  
Capital markets income 0.0 0.0 0.0 0.0  
Mortgage banking operations 0.0 0.0 0.0 0.0  
Other 0.0 0.0 0.0 0.0  
Total Non-Interest Income 20.0 20.0 42.0 39.0  
Non-interest expense:          
Salaries and employee benefits 11.0 11.0 21.0 22.0  
Other 3.0 3.0 7.0 5.0  
Total Non-Interest Expense 14.0 14.0 28.0 27.0  
Income taxes 1.0 1.0 3.0 3.0  
Net Income 5.0 5.0 11.0 9.0  
Total assets 45.0 42.0 45.0 42.0  
Total Loans and Leases 0.0 0.0 0.0 0.0  
Total deposits 0.0 0.0 0.0 0.0  
Market value of assets under administration - FNBIA, FNTC and FNIS 14,425.0 13,520.0 14,425.0 13,520.0  
Operating Segments | Insurance          
Segment Reporting Information [Line Items]          
Interest income 0.0 0.0 0.0 0.0  
Interest expense 0.0 0.0 0.0 0.0  
Net Interest Income 0.0 0.0 0.0 0.0  
Provision for Credit Losses 0.0 0.0 0.0 0.0  
Non-interest income:          
Service charges 0.0 0.0 0.0 0.0  
Interchange and card transaction fees 0.0 0.0 0.0 0.0  
Trust services 0.0 0.0 0.0 0.0  
Insurance commissions and fees 5.0 6.0 11.0 13.0  
Securities commissions and fees 0.0 0.0 0.0 0.0  
Capital markets income 0.0 0.0 0.0 0.0  
Mortgage banking operations 0.0 0.0 0.0 0.0  
Other 0.0 0.0 0.0 0.0  
Total Non-Interest Income 5.0 6.0 11.0 13.0  
Non-interest expense:          
Salaries and employee benefits 4.0 4.0 8.0 7.0  
Other 1.0 2.0 2.0 3.0  
Total Non-Interest Expense 5.0 6.0 10.0 10.0  
Income taxes 0.0 0.0 0.0 1.0  
Net Income 0.0 0.0 1.0 2.0  
Total assets 35.0 36.0 35.0 36.0  
Total Loans and Leases 0.0 0.0 0.0 0.0  
Total deposits 0.0 0.0 0.0 0.0  
Market value of assets under administration - FNBIA, FNTC and FNIS 0.0 0.0 0.0 0.0  
Parent and Other          
Segment Reporting Information [Line Items]          
Interest income 2.0 2.0 3.0 3.0  
Interest expense 14.0 8.0 29.0 14.0  
Net Interest Income (12.0) (6.0) (26.0) (11.0)  
Provision for Credit Losses 0.0 0.0 0.0 0.0  
Non-interest income:          
Service charges 0.0 0.0 0.0 0.0  
Interchange and card transaction fees 0.0 0.0 0.0 0.0  
Trust services 0.0 0.0 0.0 0.0  
Insurance commissions and fees 0.0 0.0 0.0 0.0  
Securities commissions and fees 0.0 0.0 0.0 0.0  
Capital markets income 1.0 0.0 2.0 1.0  
Mortgage banking operations 0.0 0.0 0.0 0.0  
Other (1.0) (2.0) (5.0) (4.0)  
Total Non-Interest Income 0.0 (2.0) (3.0) (3.0)  
Non-interest expense:          
Salaries and employee benefits 1.0 1.0 1.0 1.0  
Other 10.0 2.0 15.0 7.0  
Total Non-Interest Expense 11.0 3.0 16.0 8.0  
Income taxes (5.0) (3.0) (10.0) (6.0)  
Net Income (18.0) (8.0) (35.0) (16.0)  
Total assets 265.0 216.0 265.0 216.0  
Total Loans and Leases 45.0 41.0 45.0 41.0  
Total deposits (804.0) (344.0) (804.0) (344.0)  
Market value of assets under administration - FNBIA, FNTC and FNIS $ 0.0 $ 0.0 $ 0.0 $ 0.0  
[1] Amount represents loans for which we have elected the fair value option. See Note 18.