Loans and Related Allowance for Credit Losses (Commercial Lending Asset Quality Indicators) (Details) - USD ($) $ in Millions	Jun. 30, 2021	Dec. 31, 2020
Financing Receivable, Credit Quality Indicator [Line Items]
Total Loans	$ 294,704	$ 241,928
Total commercial
Financing Receivable, Credit Quality Indicator [Line Items]
Financing receivable, originated in current year	23,283	37,554
Financing receivable, originated in year one	24,980	22,152
Financing receivable, originated in year two	25,135	13,389
Financing receivable, originated in year three	16,820	10,331
Financing receivable, originated in year four	13,118	7,634
Prior	28,179	16,824
Revolving Loans	68,006	59,247
Revolving Loans Converted to Term	119	72
Total Loans	199,640	167,203
Total commercial | Commercial and industrial
Financing Receivable, Credit Quality Indicator [Line Items]
Financing receivable, originated in current year	20,371	32,019
Financing receivable, originated in year one	18,894	14,042
Financing receivable, originated in year two	14,662	8,787
Financing receivable, originated in year three	9,706	6,290
Financing receivable, originated in year four	8,508	4,466
Prior	15,498	7,492
Revolving Loans	67,542	58,905
Revolving Loans Converted to Term	119	72
Total Loans	155,300	132,073
Total commercial | Commercial real estate
Financing Receivable, Credit Quality Indicator [Line Items]
Financing receivable, originated in current year	2,255	4,028
Financing receivable, originated in year one	4,716	6,816
Financing receivable, originated in year two	9,314	3,574
Financing receivable, originated in year three	6,224	3,264
Financing receivable, originated in year four	3,965	2,741
Prior	11,026	7,951
Revolving Loans	464	342
Total Loans	37,964	28,716
Total commercial | Equipment lease financing
Financing Receivable, Credit Quality Indicator [Line Items]
Financing receivable, originated in current year	657	1,507
Financing receivable, originated in year one	1,370	1,294
Financing receivable, originated in year two	1,159	1,028
Financing receivable, originated in year three	890	777
Financing receivable, originated in year four	645	427
Prior	1,655	1,381
Total Loans	6,376	6,414
Pass Rated | Total commercial | Commercial and industrial
Financing Receivable, Credit Quality Indicator [Line Items]
Financing receivable, originated in current year	20,084	31,680
Financing receivable, originated in year one	18,350	13,340
Financing receivable, originated in year two	13,729	8,209
Financing receivable, originated in year three	8,737	5,956
Financing receivable, originated in year four	7,980	4,242
Prior	14,429	7,141
Revolving Loans	62,892	54,775
Revolving Loans Converted to Term	91	53
Total Loans	146,292	125,396
Pass Rated | Total commercial | Commercial real estate
Financing Receivable, Credit Quality Indicator [Line Items]
Financing receivable, originated in current year	2,124	3,709
Financing receivable, originated in year one	4,419	6,268
Financing receivable, originated in year two	8,354	3,426
Financing receivable, originated in year three	5,547	2,841
Financing receivable, originated in year four	3,220	2,341
Prior	8,971	6,792
Revolving Loans	414	218
Total Loans	33,049	25,595
Pass Rated | Total commercial | Equipment lease financing
Financing Receivable, Credit Quality Indicator [Line Items]
Financing receivable, originated in current year	636	1,429
Financing receivable, originated in year one	1,306	1,202
Financing receivable, originated in year two	1,097	942
Financing receivable, originated in year three	816	738
Financing receivable, originated in year four	616	405
Prior	1,647	1,350
Total Loans	6,118	6,066
Criticized | Total commercial | Commercial and industrial
Financing Receivable, Credit Quality Indicator [Line Items]
Financing receivable, originated in current year	287	339
Financing receivable, originated in year one	544	702
Financing receivable, originated in year two	933	578
Financing receivable, originated in year three	969	334
Financing receivable, originated in year four	528	224
Prior	1,069	351
Revolving Loans	4,650	4,130
Revolving Loans Converted to Term	28	19
Total Loans	9,008	6,677
Criticized | Total commercial | Commercial real estate
Financing Receivable, Credit Quality Indicator [Line Items]
Financing receivable, originated in current year	131	319
Financing receivable, originated in year one	297	548
Financing receivable, originated in year two	960	148
Financing receivable, originated in year three	677	423
Financing receivable, originated in year four	745	400
Prior	2,055	1,159
Revolving Loans	50	124
Total Loans	4,915	3,121
Criticized | Total commercial | Equipment lease financing
Financing Receivable, Credit Quality Indicator [Line Items]
Financing receivable, originated in current year	21	78
Financing receivable, originated in year one	64	92
Financing receivable, originated in year two	62	86
Financing receivable, originated in year three	74	39
Financing receivable, originated in year four	29	22
Prior	8	31
Total Loans	$ 258	$ 348