Allowance for Credit Losses (Non-Accrual Loans and Leases and Loans and Leases Past Due) (Details) - USD ($) $ in Millions	Sep. 30, 2025	Dec. 31, 2024
Financing Receivable, Past Due [Line Items]
Loans and leases	$ 48,462	$ 37,681
Non-Accrual	120	96
Loans Insured or Guaranteed by US Government Authorities [Member]
Financing Receivable, Past Due [Line Items]
Non-Accrual	37	41
Greater than 30 to 59 Days Past Due
Financing Receivable, Past Due [Line Items]
Loans and leases	44	58
60 to 89 Days Past Due
Financing Receivable, Past Due [Line Items]
Loans and leases	41	47
90 Days or More and Accruing (2)
Financing Receivable, Past Due [Line Items]
Loans and leases	78	73
90 Days or More and Accruing (2) \| Loans Insured or Guaranteed by US Government Authorities [Member]
Financing Receivable, Past Due [Line Items]
Loans and leases	33	32
Total Past Due
Financing Receivable, Past Due [Line Items]
Loans and leases	163	178
Current and Other
Financing Receivable, Past Due [Line Items]
Loans and leases	48,179	37,407
Commercial real estate
Financing Receivable, Past Due [Line Items]
Loans and leases	28,620	19,567
Commercial real estate \| Non-owner occupied term
Financing Receivable, Past Due [Line Items]
Loans and leases	8,444	6,278
Non-Accrual	38	14
Commercial real estate \| Owner occupied term
Financing Receivable, Past Due [Line Items]
Loans and leases	7,361	5,270
Non-Accrual	15	25
Commercial real estate \| Multifamily
Financing Receivable, Past Due [Line Items]
Loans and leases	10,377	5,804
Non-Accrual	0	0
Commercial real estate \| Construction & development
Financing Receivable, Past Due [Line Items]
Loans and leases	2,071	1,983
Non-Accrual	0	0
Commercial real estate \| Residential development
Financing Receivable, Past Due [Line Items]
Loans and leases	367	232
Non-Accrual	0	0
Commercial real estate \| Greater than 30 to 59 Days Past Due \| Non-owner occupied term
Financing Receivable, Past Due [Line Items]
Loans and leases	8	28
Commercial real estate \| Greater than 30 to 59 Days Past Due \| Owner occupied term
Financing Receivable, Past Due [Line Items]
Loans and leases	3	1
Commercial real estate \| Greater than 30 to 59 Days Past Due \| Multifamily
Financing Receivable, Past Due [Line Items]
Loans and leases	0	0
Commercial real estate \| Greater than 30 to 59 Days Past Due \| Construction & development
Financing Receivable, Past Due [Line Items]
Loans and leases	0	0
Commercial real estate \| Greater than 30 to 59 Days Past Due \| Residential development
Financing Receivable, Past Due [Line Items]
Loans and leases	0	0
Commercial real estate \| 60 to 89 Days Past Due \| Non-owner occupied term
Financing Receivable, Past Due [Line Items]
Loans and leases	2	0
Commercial real estate \| 60 to 89 Days Past Due \| Owner occupied term
Financing Receivable, Past Due [Line Items]
Loans and leases	0	0
Commercial real estate \| 60 to 89 Days Past Due \| Multifamily
Financing Receivable, Past Due [Line Items]
Loans and leases	0	0
Commercial real estate \| 60 to 89 Days Past Due \| Construction & development
Financing Receivable, Past Due [Line Items]
Loans and leases	0	0
Commercial real estate \| 60 to 89 Days Past Due \| Residential development
Financing Receivable, Past Due [Line Items]
Loans and leases	0	0
Commercial real estate \| 90 Days or More and Accruing (2) \| Non-owner occupied term
Financing Receivable, Past Due [Line Items]
Loans and leases	0	0
Commercial real estate \| 90 Days or More and Accruing (2) \| Owner occupied term
Financing Receivable, Past Due [Line Items]
Loans and leases	0	0
Commercial real estate \| 90 Days or More and Accruing (2) \| Multifamily
Financing Receivable, Past Due [Line Items]
Loans and leases	0	0
Commercial real estate \| 90 Days or More and Accruing (2) \| Construction & development
Financing Receivable, Past Due [Line Items]
Loans and leases	0	0
Commercial real estate \| 90 Days or More and Accruing (2) \| Residential development
Financing Receivable, Past Due [Line Items]
Loans and leases	0	0
Commercial real estate \| Total Past Due \| Non-owner occupied term
Financing Receivable, Past Due [Line Items]
Loans and leases	10	28
Commercial real estate \| Total Past Due \| Owner occupied term
Financing Receivable, Past Due [Line Items]
Loans and leases	3	1
Commercial real estate \| Total Past Due \| Multifamily
Financing Receivable, Past Due [Line Items]
Loans and leases	0	0
Commercial real estate \| Total Past Due \| Construction & development
Financing Receivable, Past Due [Line Items]
Loans and leases	0	0
Commercial real estate \| Total Past Due \| Residential development
Financing Receivable, Past Due [Line Items]
Loans and leases	0	0
Commercial real estate \| Current and Other \| Non-owner occupied term
Financing Receivable, Past Due [Line Items]
Loans and leases	8,396	6,236
Commercial real estate \| Current and Other \| Owner occupied term
Financing Receivable, Past Due [Line Items]
Loans and leases	7,343	5,244
Commercial real estate \| Current and Other \| Multifamily
Financing Receivable, Past Due [Line Items]
Loans and leases	10,377	5,804
Commercial real estate \| Current and Other \| Construction & development
Financing Receivable, Past Due [Line Items]
Loans and leases	2,071	1,983
Commercial real estate \| Current and Other \| Residential development
Financing Receivable, Past Due [Line Items]
Loans and leases	367	232
Commercial
Financing Receivable, Past Due [Line Items]
Loans and leases	11,786	9,969
Commercial \| Term
Financing Receivable, Past Due [Line Items]
Loans and leases	6,590	5,538
Non-Accrual	26	29
Commercial \| Lines of credit & other
Financing Receivable, Past Due [Line Items]
Loans and leases	3,582	2,770
Non-Accrual	24	7
Commercial \| Leases & equipment finance
Financing Receivable, Past Due [Line Items]
Loans and leases	1,614	1,661
Non-Accrual	17	21
Commercial \| Greater than 30 to 59 Days Past Due \| Term
Financing Receivable, Past Due [Line Items]
Loans and leases	4	2
Commercial \| Greater than 30 to 59 Days Past Due \| Lines of credit & other
Financing Receivable, Past Due [Line Items]
Loans and leases	4	5
Commercial \| Greater than 30 to 59 Days Past Due \| Leases & equipment finance
Financing Receivable, Past Due [Line Items]
Loans and leases	15	15
Commercial \| 60 to 89 Days Past Due \| Term
Financing Receivable, Past Due [Line Items]
Loans and leases	5	1
Commercial \| 60 to 89 Days Past Due \| Lines of credit & other
Financing Receivable, Past Due [Line Items]
Loans and leases	3	6
Commercial \| 60 to 89 Days Past Due \| Leases & equipment finance
Financing Receivable, Past Due [Line Items]
Loans and leases	15	17
Commercial \| 90 Days or More and Accruing (2) \| Term
Financing Receivable, Past Due [Line Items]
Loans and leases	0	0
Commercial \| 90 Days or More and Accruing (2) \| Lines of credit & other
Financing Receivable, Past Due [Line Items]
Loans and leases	0	0
Commercial \| 90 Days or More and Accruing (2) \| Leases & equipment finance
Financing Receivable, Past Due [Line Items]
Loans and leases	5	5
Commercial \| Total Past Due \| Term
Financing Receivable, Past Due [Line Items]
Loans and leases	9	3
Commercial \| Total Past Due \| Lines of credit & other
Financing Receivable, Past Due [Line Items]
Loans and leases	7	11
Commercial \| Total Past Due \| Leases & equipment finance
Financing Receivable, Past Due [Line Items]
Loans and leases	35	37
Commercial \| Current and Other \| Term
Financing Receivable, Past Due [Line Items]
Loans and leases	6,555	5,506
Commercial \| Current and Other \| Lines of credit & other
Financing Receivable, Past Due [Line Items]
Loans and leases	3,551	2,752
Commercial \| Current and Other \| Leases & equipment finance
Financing Receivable, Past Due [Line Items]
Loans and leases	1,562	1,603
Residential
Financing Receivable, Past Due [Line Items]
Loans and leases	7,875	7,965
Residential \| Mortgage
Financing Receivable, Past Due [Line Items]
Loans and leases	5,722	5,933
Non-Accrual	0	0
Residential \| Home equity loans & lines
Financing Receivable, Past Due [Line Items]
Loans and leases	2,153	2,032
Non-Accrual	0	0
Residential \| Greater than 30 to 59 Days Past Due \| Mortgage
Financing Receivable, Past Due [Line Items]
Loans and leases	0	0
Residential \| Greater than 30 to 59 Days Past Due \| Home equity loans & lines
Financing Receivable, Past Due [Line Items]
Loans and leases	9	6
Residential \| 60 to 89 Days Past Due \| Mortgage
Financing Receivable, Past Due [Line Items]
Loans and leases	12	18
Residential \| 60 to 89 Days Past Due \| Home equity loans & lines
Financing Receivable, Past Due [Line Items]
Loans and leases	4	5
Residential \| 90 Days or More and Accruing (2) \| Mortgage
Financing Receivable, Past Due [Line Items]
Loans and leases	65	61
Residential \| 90 Days or More and Accruing (2) \| Mortgage \| GNMA Loans
Financing Receivable, Past Due [Line Items]
GNMA Loans past due by 90 days, but not yet repurchased	2	2
Residential \| 90 Days or More and Accruing (2) \| Home equity loans & lines
Financing Receivable, Past Due [Line Items]
Loans and leases	8	7
Residential \| Total Past Due \| Mortgage
Financing Receivable, Past Due [Line Items]
Loans and leases	77	79
Residential \| Total Past Due \| Home equity loans & lines
Financing Receivable, Past Due [Line Items]
Loans and leases	21	18
Residential \| Current and Other \| Mortgage
Financing Receivable, Past Due [Line Items]
Loans and leases	5,645	5,854
Residential \| Current and Other \| Home equity loans & lines
Financing Receivable, Past Due [Line Items]
Loans and leases	2,132	2,014
Consumer & other
Financing Receivable, Past Due [Line Items]
Loans and leases	181	180
Non-Accrual	0	0
Consumer & other \| Greater than 30 to 59 Days Past Due
Financing Receivable, Past Due [Line Items]
Loans and leases	1	1
Consumer & other \| 60 to 89 Days Past Due
Financing Receivable, Past Due [Line Items]
Loans and leases	0	0
Consumer & other \| 90 Days or More and Accruing (2)
Financing Receivable, Past Due [Line Items]
Loans and leases	0	0
Consumer & other \| Total Past Due
Financing Receivable, Past Due [Line Items]
Loans and leases	1	1
Consumer & other \| Current and Other
Financing Receivable, Past Due [Line Items]
Loans and leases	$ 180	$ 179