Loans - Commercial Banking: Risk Profile by Internal Risk Rating (Details) - USD ($) $ in Millions	Mar. 31, 2024	Dec. 31, 2023
Financing Receivable, Allowance for Credit Loss [Line Items]
Total loans held for investment	$ 315,154	$ 320,472
Commercial Banking:
Financing Receivable, Allowance for Credit Loss [Line Items]
Term Loans by Vintage Year, Year 1	1,790	10,556
Term Loans by Vintage Year, Year 2	10,037	18,879
Term Loans by Vintage Year, Year 3	18,299	11,282
Term Loans by Vintage Year, Year 4	10,790	5,124
Term Loans by Vintage Year, Year 5	4,859	5,444
Prior	14,907	10,271
Total Term Loans	60,682	61,556
Revolving Loans	28,622	28,740
Revolving Loans Converted to Term	157	192
Total loans held for investment	89,461	90,488
Commercial Banking: | Commercial and multifamily real estate
Financing Receivable, Allowance for Credit Loss [Line Items]
Term Loans by Vintage Year, Year 1	711	3,281
Term Loans by Vintage Year, Year 2	2,913	6,185
Term Loans by Vintage Year, Year 3	5,938	3,603
Term Loans by Vintage Year, Year 4	3,376	1,303
Term Loans by Vintage Year, Year 5	1,214	2,614
Prior	6,910	4,737
Total Term Loans	21,062	21,723
Revolving Loans	13,183	12,698
Revolving Loans Converted to Term	27	25
Total loans held for investment	34,272	34,446
Commercial Banking: | Commercial and multifamily real estate | Noncriticized
Financing Receivable, Allowance for Credit Loss [Line Items]
Term Loans by Vintage Year, Year 1	646	3,068
Term Loans by Vintage Year, Year 2	2,794	4,665
Term Loans by Vintage Year, Year 3	4,392	2,773
Term Loans by Vintage Year, Year 4	2,573	1,019
Term Loans by Vintage Year, Year 5	994	2,104
Prior	5,280	3,670
Total Term Loans	16,679	17,299
Revolving Loans	13,046	12,565
Revolving Loans Converted to Term	25	25
Total loans held for investment	29,750	29,889
Commercial Banking: | Commercial and multifamily real estate | Criticized | Criticized performing
Financing Receivable, Allowance for Credit Loss [Line Items]
Term Loans by Vintage Year, Year 1	53	148
Term Loans by Vintage Year, Year 2	59	1,494
Term Loans by Vintage Year, Year 3	1,501	706
Term Loans by Vintage Year, Year 4	685	284
Term Loans by Vintage Year, Year 5	220	463
Prior	1,331	904
Total Term Loans	3,849	3,999
Revolving Loans	130	133
Revolving Loans Converted to Term	2	0
Total loans held for investment	3,981	4,132
Commercial Banking: | Commercial and multifamily real estate | Criticized | Criticized nonperforming
Financing Receivable, Allowance for Credit Loss [Line Items]
Term Loans by Vintage Year, Year 1	12	65
Term Loans by Vintage Year, Year 2	60	26
Term Loans by Vintage Year, Year 3	45	124
Term Loans by Vintage Year, Year 4	118	0
Term Loans by Vintage Year, Year 5	0	47
Prior	299	163
Total Term Loans	534	425
Revolving Loans	7	0
Revolving Loans Converted to Term	0	0
Total loans held for investment	541	425
Commercial Banking: | Commercial and industrial
Financing Receivable, Allowance for Credit Loss [Line Items]
Term Loans by Vintage Year, Year 1	1,079	7,275
Term Loans by Vintage Year, Year 2	7,124	12,694
Term Loans by Vintage Year, Year 3	12,361	7,679
Term Loans by Vintage Year, Year 4	7,414	3,821
Term Loans by Vintage Year, Year 5	3,645	2,830
Prior	7,997	5,534
Total Term Loans	39,620	39,833
Revolving Loans	15,439	16,042
Revolving Loans Converted to Term	130	167
Total loans held for investment	55,189	56,042
Commercial Banking: | Commercial and industrial | Noncriticized
Financing Receivable, Allowance for Credit Loss [Line Items]
Term Loans by Vintage Year, Year 1	1,037	6,909
Term Loans by Vintage Year, Year 2	6,784	11,935
Term Loans by Vintage Year, Year 3	11,627	6,994
Term Loans by Vintage Year, Year 4	6,701	3,566
Term Loans by Vintage Year, Year 5	3,341	2,359
Prior	7,339	5,117
Total Term Loans	36,829	36,880
Revolving Loans	14,096	14,822
Revolving Loans Converted to Term	129	167
Total loans held for investment	51,054	51,869
Commercial Banking: | Commercial and industrial | Criticized | Criticized performing
Financing Receivable, Allowance for Credit Loss [Line Items]
Term Loans by Vintage Year, Year 1	42	353
Term Loans by Vintage Year, Year 2	328	706
Term Loans by Vintage Year, Year 3	638	655
Term Loans by Vintage Year, Year 4	672	237
Term Loans by Vintage Year, Year 5	126	348
Prior	437	349
Total Term Loans	2,243	2,648
Revolving Loans	1,284	1,189
Revolving Loans Converted to Term	1	0
Total loans held for investment	3,528	3,837
Commercial Banking: | Commercial and industrial | Criticized | Criticized nonperforming
Financing Receivable, Allowance for Credit Loss [Line Items]
Term Loans by Vintage Year, Year 1	0	13
Term Loans by Vintage Year, Year 2	12	53
Term Loans by Vintage Year, Year 3	96	30
Term Loans by Vintage Year, Year 4	41	18
Term Loans by Vintage Year, Year 5	178	123
Prior	221	68
Total Term Loans	548	305
Revolving Loans	59	31
Revolving Loans Converted to Term	0	0
Total loans held for investment	$ 607	$ 336