Loans and Allowance for Loan Losses - Schedule of Rollforward of Allowance for Loan Losses (Details) - USD ($) $ in Millions	3 Months Ended	6 Months Ended	12 Months Ended
Jun. 30, 2026	Jun. 30, 2025	Jun. 30, 2026	Jun. 30, 2025	Dec. 31, 2025
Allowance for loan losses:
Beginning balance	$ 942	$ 418	$ 442	$ 414	$ 414
Purchased credit deteriorated loans			237
Purchased seasoned loans			241
Charge-offs	(58)	(24)	(115)	(40)	(96)
Recoveries	10	5	18	8
Provision for (reversal of) loan losses	62	23	133	40
Ending balance	956	422	956	422	442
Commercial & Industrial
Allowance for loan losses:
Beginning balance	489	230	255	221	221
Purchased credit deteriorated loans			110
Purchased seasoned loans			106
Charge-offs	(43)	(20)	(88)	(34)
Recoveries	6	3	10	5
Provision for (reversal of) loan losses	48	20	107	41
Ending balance	500	233	500	233	255
Commercial Real Estate
Allowance for loan losses:
Beginning balance	217	99	95	111	111
Purchased credit deteriorated loans			102
Purchased seasoned loans			67
Charge-offs	(1)	(1)	(1)	0
Recoveries	0	0	0	0
Provision for (reversal of) loan losses	0	3	(47)	(10)
Ending balance	216	101	216	101	95
Consumer
Allowance for loan losses:
Beginning balance	236	89	92	82	82
Purchased credit deteriorated loans			25
Purchased seasoned loans			68
Charge-offs	(14)	(3)	(26)	(6)
Recoveries	4	2	8	3
Provision for (reversal of) loan losses	14	0	73	9
Ending balance	$ 240	$ 88	$ 240	$ 88	$ 92

A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.

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Amount excluding accrued interest, of allowance for credit loss on financing receivable. Excludes net investment in lease.

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Amount of increase in allowance for credit loss for financing receivable from purchased seasoned loan.

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Amount, excluding accrued interest, of increase in allowance for credit loss on financing receivable from recovery. Excludes net investment in lease.

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Amount, excluding accrued interest, of decrease in allowance for credit loss on financing receivable from writeoff. Excludes net investment in lease.

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Amount, excluding accrued interest, of allowance for credit loss at acquisition date of financing receivable purchased with credit deterioration. Excludes net investment in lease.

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Amount of expense related loan transactions, lease transactions, credit loss from transactions other than loan and lease transactions, and other loss based on assessment of uncollectability from the counterparty to reduce the account to their net realizable value.

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