Loans and Allowance for Loan Losses - Schedule of Current, Accruing Past Due, and Non-Accrual Loans by Portfolio Class (Details) - USD ($) $ in Millions	Mar. 31, 2026	Dec. 31, 2025
Financing Receivable, Nonaccrual [Line Items]
Loans, net of deferred fees and costs	$ 85,197	$ 39,154
Non-accrual with an ALL	332	103
Non-accrual without an ALL	127	30
Accrued interest receivable	340	151
Deferred loan costs (fees)	(330)	(314)
Total commercial and industrial
Financing Receivable, Nonaccrual [Line Items]
Loans, net of deferred fees and costs	48,197	22,296
Non-accrual with an ALL	164	38
Non-accrual without an ALL	84	16
Total commercial and industrial \| Commercial, financial and agricultural
Financing Receivable, Nonaccrual [Line Items]
Loans, net of deferred fees and costs	34,151	16,549
Non-accrual with an ALL	95	35
Non-accrual without an ALL	79	13
Total commercial and industrial \| Owner-occupied
Financing Receivable, Nonaccrual [Line Items]
Loans, net of deferred fees and costs	14,046	5,747
Non-accrual with an ALL	69	3
Non-accrual without an ALL	5	3
Total commercial real estate
Financing Receivable, Nonaccrual [Line Items]
Loans, net of deferred fees and costs	23,760	11,356
Non-accrual with an ALL	83	36
Non-accrual without an ALL	43	14
Total commercial real estate \| Investment properties
Financing Receivable, Nonaccrual [Line Items]
Loans, net of deferred fees and costs	20,888	9,496
Non-accrual with an ALL	79	34
Non-accrual without an ALL	42	14
Total commercial real estate \| 1-4 family properties
Financing Receivable, Nonaccrual [Line Items]
Loans, net of deferred fees and costs	1,935	1,284
Non-accrual with an ALL	4	2
Non-accrual without an ALL	1	0
Total commercial real estate \| Land and development
Financing Receivable, Nonaccrual [Line Items]
Loans, net of deferred fees and costs	937	576
Non-accrual with an ALL	0	0
Non-accrual without an ALL	0	0
Total consumer
Financing Receivable, Nonaccrual [Line Items]
Loans, net of deferred fees and costs	13,240	5,502
Non-accrual with an ALL	85	29
Non-accrual without an ALL	0	0
Total consumer \| Consumer mortgages
Financing Receivable, Nonaccrual [Line Items]
Loans, net of deferred fees and costs	8,234	3,456
Non-accrual with an ALL	61	23
Non-accrual without an ALL	0	0
Total consumer \| Home equity
Financing Receivable, Nonaccrual [Line Items]
Loans, net of deferred fees and costs	3,157	1,374
Non-accrual with an ALL	18	6
Non-accrual without an ALL	0	0
Total consumer \| Credit cards
Financing Receivable, Nonaccrual [Line Items]
Loans, net of deferred fees and costs	227	53
Non-accrual with an ALL	0	0
Non-accrual without an ALL	0	0
Total consumer \| Other consumer loans
Financing Receivable, Nonaccrual [Line Items]
Loans, net of deferred fees and costs	1,622	619
Non-accrual with an ALL	6	0
Non-accrual without an ALL	0	0
Current
Financing Receivable, Nonaccrual [Line Items]
Loans, net of deferred fees and costs	84,621	38,964
Current \| Total commercial and industrial
Financing Receivable, Nonaccrual [Line Items]
Loans, net of deferred fees and costs	47,893	22,216
Current \| Total commercial and industrial \| Commercial, financial and agricultural
Financing Receivable, Nonaccrual [Line Items]
Loans, net of deferred fees and costs	33,930	16,478
Current \| Total commercial and industrial \| Owner-occupied
Financing Receivable, Nonaccrual [Line Items]
Loans, net of deferred fees and costs	13,963	5,738
Current \| Total commercial real estate
Financing Receivable, Nonaccrual [Line Items]
Loans, net of deferred fees and costs	23,628	11,304
Current \| Total commercial real estate \| Investment properties
Financing Receivable, Nonaccrual [Line Items]
Loans, net of deferred fees and costs	20,763	9,448
Current \| Total commercial real estate \| 1-4 family properties
Financing Receivable, Nonaccrual [Line Items]
Loans, net of deferred fees and costs	1,928	1,280
Current \| Total commercial real estate \| Land and development
Financing Receivable, Nonaccrual [Line Items]
Loans, net of deferred fees and costs	937	576
Current \| Total consumer
Financing Receivable, Nonaccrual [Line Items]
Loans, net of deferred fees and costs	13,100	5,444
Current \| Total consumer \| Consumer mortgages
Financing Receivable, Nonaccrual [Line Items]
Loans, net of deferred fees and costs	8,153	3,417
Current \| Total consumer \| Home equity
Financing Receivable, Nonaccrual [Line Items]
Loans, net of deferred fees and costs	3,120	1,360
Current \| Total consumer \| Credit cards
Financing Receivable, Nonaccrual [Line Items]
Loans, net of deferred fees and costs	223	51
Current \| Total consumer \| Other consumer loans
Financing Receivable, Nonaccrual [Line Items]
Loans, net of deferred fees and costs	1,604	616
Accruing 30-89 Days Past Due
Financing Receivable, Nonaccrual [Line Items]
Loans, net of deferred fees and costs	109	54
Accruing 30-89 Days Past Due \| Total commercial and industrial
Financing Receivable, Nonaccrual [Line Items]
Loans, net of deferred fees and costs	51	24
Accruing 30-89 Days Past Due \| Total commercial and industrial \| Commercial, financial and agricultural
Financing Receivable, Nonaccrual [Line Items]
Loans, net of deferred fees and costs	42	21
Accruing 30-89 Days Past Due \| Total commercial and industrial \| Owner-occupied
Financing Receivable, Nonaccrual [Line Items]
Loans, net of deferred fees and costs	9	3
Accruing 30-89 Days Past Due \| Total commercial real estate
Financing Receivable, Nonaccrual [Line Items]
Loans, net of deferred fees and costs	6	2
Accruing 30-89 Days Past Due \| Total commercial real estate \| Investment properties
Financing Receivable, Nonaccrual [Line Items]
Loans, net of deferred fees and costs	4	0
Accruing 30-89 Days Past Due \| Total commercial real estate \| 1-4 family properties
Financing Receivable, Nonaccrual [Line Items]
Loans, net of deferred fees and costs	2	2
Accruing 30-89 Days Past Due \| Total commercial real estate \| Land and development
Financing Receivable, Nonaccrual [Line Items]
Loans, net of deferred fees and costs	0	0
Accruing 30-89 Days Past Due \| Total consumer
Financing Receivable, Nonaccrual [Line Items]
Loans, net of deferred fees and costs	52	28
Accruing 30-89 Days Past Due \| Total consumer \| Consumer mortgages
Financing Receivable, Nonaccrual [Line Items]
Loans, net of deferred fees and costs	20	16
Accruing 30-89 Days Past Due \| Total consumer \| Home equity
Financing Receivable, Nonaccrual [Line Items]
Loans, net of deferred fees and costs	18	8
Accruing 30-89 Days Past Due \| Total consumer \| Credit cards
Financing Receivable, Nonaccrual [Line Items]
Loans, net of deferred fees and costs	2	1
Accruing 30-89 Days Past Due \| Total consumer \| Other consumer loans
Financing Receivable, Nonaccrual [Line Items]
Loans, net of deferred fees and costs	12	3
Accruing 90 Days or Greater Past Due
Financing Receivable, Nonaccrual [Line Items]
Loans, net of deferred fees and costs	8	3
Accruing 90 Days or Greater Past Due \| Total commercial and industrial
Financing Receivable, Nonaccrual [Line Items]
Loans, net of deferred fees and costs	5	2
Accruing 90 Days or Greater Past Due \| Total commercial and industrial \| Commercial, financial and agricultural
Financing Receivable, Nonaccrual [Line Items]
Loans, net of deferred fees and costs	5	2
Accruing 90 Days or Greater Past Due \| Total commercial and industrial \| Owner-occupied
Financing Receivable, Nonaccrual [Line Items]
Loans, net of deferred fees and costs	0	0
Accruing 90 Days or Greater Past Due \| Total commercial real estate
Financing Receivable, Nonaccrual [Line Items]
Loans, net of deferred fees and costs	0	0
Accruing 90 Days or Greater Past Due \| Total commercial real estate \| Investment properties
Financing Receivable, Nonaccrual [Line Items]
Loans, net of deferred fees and costs	0	0
Accruing 90 Days or Greater Past Due \| Total commercial real estate \| 1-4 family properties
Financing Receivable, Nonaccrual [Line Items]
Loans, net of deferred fees and costs	0	0
Accruing 90 Days or Greater Past Due \| Total commercial real estate \| Land and development
Financing Receivable, Nonaccrual [Line Items]
Loans, net of deferred fees and costs	0	0
Accruing 90 Days or Greater Past Due \| Total consumer
Financing Receivable, Nonaccrual [Line Items]
Loans, net of deferred fees and costs	3	1
Accruing 90 Days or Greater Past Due \| Total consumer \| Consumer mortgages
Financing Receivable, Nonaccrual [Line Items]
Loans, net of deferred fees and costs	0	0
Accruing 90 Days or Greater Past Due \| Total consumer \| Home equity
Financing Receivable, Nonaccrual [Line Items]
Loans, net of deferred fees and costs	1	0
Accruing 90 Days or Greater Past Due \| Total consumer \| Credit cards
Financing Receivable, Nonaccrual [Line Items]
Loans, net of deferred fees and costs	2	1
Accruing 90 Days or Greater Past Due \| Total consumer \| Other consumer loans
Financing Receivable, Nonaccrual [Line Items]
Loans, net of deferred fees and costs	0	0
Total Accruing Past Due
Financing Receivable, Nonaccrual [Line Items]
Loans, net of deferred fees and costs	117	57
Total Accruing Past Due \| Total commercial and industrial
Financing Receivable, Nonaccrual [Line Items]
Loans, net of deferred fees and costs	56	26
Total Accruing Past Due \| Total commercial and industrial \| Commercial, financial and agricultural
Financing Receivable, Nonaccrual [Line Items]
Loans, net of deferred fees and costs	47	23
Total Accruing Past Due \| Total commercial and industrial \| Owner-occupied
Financing Receivable, Nonaccrual [Line Items]
Loans, net of deferred fees and costs	9	3
Total Accruing Past Due \| Total commercial real estate
Financing Receivable, Nonaccrual [Line Items]
Loans, net of deferred fees and costs	6	2
Total Accruing Past Due \| Total commercial real estate \| Investment properties
Financing Receivable, Nonaccrual [Line Items]
Loans, net of deferred fees and costs	4	0
Total Accruing Past Due \| Total commercial real estate \| 1-4 family properties
Financing Receivable, Nonaccrual [Line Items]
Loans, net of deferred fees and costs	2	2
Total Accruing Past Due \| Total commercial real estate \| Land and development
Financing Receivable, Nonaccrual [Line Items]
Loans, net of deferred fees and costs	0	0
Total Accruing Past Due \| Total consumer
Financing Receivable, Nonaccrual [Line Items]
Loans, net of deferred fees and costs	55	29
Total Accruing Past Due \| Total consumer \| Consumer mortgages
Financing Receivable, Nonaccrual [Line Items]
Loans, net of deferred fees and costs	20	16
Total Accruing Past Due \| Total consumer \| Home equity
Financing Receivable, Nonaccrual [Line Items]
Loans, net of deferred fees and costs	19	8
Total Accruing Past Due \| Total consumer \| Credit cards
Financing Receivable, Nonaccrual [Line Items]
Loans, net of deferred fees and costs	4	2
Total Accruing Past Due \| Total consumer \| Other consumer loans
Financing Receivable, Nonaccrual [Line Items]
Loans, net of deferred fees and costs	$ 12	$ 3

Amount, after allowance for credit loss, of accrued interest on financing receivable.

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Amortized cost excluding accrued interest, before allowance for credit loss, of financing receivable. Excludes net investment in lease.

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Amortized cost excluding accrued interest, of financing receivable on nonaccrual status. Excludes net investment in lease.

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Amount of unamortized loan commitment, origination, and other costs (fees) on financing receivable recognized as adjustment to yield. Excludes financing receivable covered under loss sharing agreement.

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