Loans and Related Allowance for Credit Losses (Commercial Lending Asset Quality Indicators) (Details) - USD ($) $ in Millions	Sep. 30, 2020	Dec. 31, 2019
Financing Receivable, Credit Quality Indicator [Line Items]
Total Loans	$ 249,279	$ 239,843
Total commercial
Financing Receivable, Credit Quality Indicator [Line Items]
Financing receivable, originated in 2020	35,245
Financing receivable, originated in 2019	23,543
Financing receivable, originated in 2018	14,782
Financing receivable, originated in 2017	11,417
Financing receivable, originated in 2016	8,230
Prior	18,261
Revolving Loans	61,142
Revolving Loans Converted to Term	74
Total Loans	172,694	160,602
Total commercial \| Commercial and industrial [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Financing receivable, originated in 2020	30,716
Financing receivable, originated in 2019	15,499
Financing receivable, originated in 2018	9,966
Financing receivable, originated in 2017	6,856
Financing receivable, originated in 2016	4,748
Prior	8,447
Revolving Loans	60,881
Revolving Loans Converted to Term	74
Total Loans	137,187	125,337
Total commercial \| Commercial Real Estate [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Financing receivable, originated in 2020	3,420
Financing receivable, originated in 2019	6,691
Financing receivable, originated in 2018	3,678
Financing receivable, originated in 2017	3,689
Financing receivable, originated in 2016	2,962
Prior	8,327
Revolving Loans	261
Revolving Loans Converted to Term
Total Loans	29,028	28,110
Total commercial \| Equipment Lease Financing [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Financing receivable, originated in 2020	1,109
Financing receivable, originated in 2019	1,353
Financing receivable, originated in 2018	1,138
Financing receivable, originated in 2017	872
Financing receivable, originated in 2016	520
Prior	1,487
Total Loans	6,479	7,155
Pass [Member] \| Total commercial
Financing Receivable, Credit Quality Indicator [Line Items]
Total Loans		154,076
Pass [Member] \| Total commercial \| Commercial and industrial [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Financing receivable, originated in 2020	30,385
Financing receivable, originated in 2019	14,778
Financing receivable, originated in 2018	9,241
Financing receivable, originated in 2017	6,474
Financing receivable, originated in 2016	4,531
Prior	7,916
Revolving Loans	56,000
Revolving Loans Converted to Term	55
Total Loans	129,380	119,761
Pass [Member] \| Total commercial \| Commercial Real Estate [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Financing receivable, originated in 2020	3,226
Financing receivable, originated in 2019	6,552
Financing receivable, originated in 2018	3,625
Financing receivable, originated in 2017	3,384
Financing receivable, originated in 2016	2,622
Prior	7,574
Revolving Loans	164
Total Loans	27,147	27,424
Pass [Member] \| Total commercial \| Equipment Lease Financing [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Financing receivable, originated in 2020	1,048
Financing receivable, originated in 2019	1,258
Financing receivable, originated in 2018	1,043
Financing receivable, originated in 2017	826
Financing receivable, originated in 2016	494
Prior	1,454
Total Loans	6,123	6,891
Criticized [Member] \| Total commercial
Financing Receivable, Credit Quality Indicator [Line Items]
Total Loans		6,526
Criticized [Member] \| Total commercial \| Commercial and industrial [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Financing receivable, originated in 2020	331
Financing receivable, originated in 2019	721
Financing receivable, originated in 2018	725
Financing receivable, originated in 2017	382
Financing receivable, originated in 2016	217
Prior	531
Revolving Loans	4,881
Revolving Loans Converted to Term	19
Total Loans	7,807	5,576
Criticized [Member] \| Total commercial \| Commercial Real Estate [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Financing receivable, originated in 2020	194
Financing receivable, originated in 2019	139
Financing receivable, originated in 2018	53
Financing receivable, originated in 2017	305
Financing receivable, originated in 2016	340
Prior	753
Revolving Loans	97
Total Loans	1,881	686
Criticized [Member] \| Total commercial \| Equipment Lease Financing [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Financing receivable, originated in 2020	61
Financing receivable, originated in 2019	95
Financing receivable, originated in 2018	95
Financing receivable, originated in 2017	46
Financing receivable, originated in 2016	26
Prior	33
Total Loans	$ 356	$ 264

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