Loans and Related Allowance for Credit Losses, Commercial Loan Categories by Risk Categories and Vintage (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022	Dec. 31, 2022
Financing Receivable and Net Investment in Lease, Excluding Accrued Interest, before Allowance for Credit Loss, by Origination Year [Abstract]
Total loans	$ 942,424	$ 945,906	$ 942,424	$ 945,906	$ 955,871
Total Commercial [Member]
Financing Receivable and Net Investment in Lease, Excluding Accrued Interest, before Allowance for Credit Loss, by Origination Year [Abstract]
Term loans by origination year, current fiscal year, total	52,228		52,228		108,198
Term loans by origination year, fiscal year before current fiscal year, total	87,770		87,770		77,734
Term loans by origination year, two years before current fiscal year, total	65,839		65,839		31,315
Term loans by origination year, three years before current fiscal year, total	25,724		25,724		35,124
Term loans by origination year, four years before current fiscal year, total	29,836		29,836		16,484
Term loans by origination year, more than five years before current fiscal year, total	31,736		31,736		25,907
Revolving loans, total	257,310		257,310		261,762
Revolving loans converted to term loans, total	608		608		992
Total loans	551,051		551,051		557,516
Total Commercial [Member] | Pass [Member]
Financing Receivable and Net Investment in Lease, Excluding Accrued Interest, before Allowance for Credit Loss, by Origination Year [Abstract]
Total loans	519,200		519,200
Total Commercial [Member] | Criticized [Member]
Financing Receivable and Net Investment in Lease, Excluding Accrued Interest, before Allowance for Credit Loss, by Origination Year [Abstract]
Total loans	31,900		31,900
Total Commercial [Member] | Commercial and industrial loans [Member]
Financing Receivable, Excluding Accrued Interest, before Allowance for Credit Loss, by Origination Year [Abstract]
Term loans by origination year, current fiscal year, finance receivable	33,660		33,660		62,518
Term loans by origination year, fiscal year before current fiscal year, finance receivable	44,068		44,068		32,620
Term loans by origination year, two years before current fiscal year, finance receivable	24,948		24,948		11,606
Term loans by origination year, three years before current fiscal year, finance receivable	9,513		9,513		14,161
Term loans by origination year, four years before current fiscal year, finance receivable	12,740		12,740		3,950
Term loans by origination year, more than five years before current fiscal year, finance receivable	6,442		6,442		6,271
Revolving loans, finance receivable	250,773		250,773		254,838
Revolving loans converted to term loans, finance receivable	383		383		842
Total loans	382,527		382,527		386,806
Financing Receivable, Excluding Accrued Interest, Allowance for Credit Loss, Writeoff, by Origination Year [Abstract]
Term loans by origination year, current fiscal year, charge-offs			86
Term loans by origination year, fiscal year before current fiscal year, charge-offs			18
Term loans by origination year, two years before current fiscal year, charge-offs			28
Term loans by origination year, three years before current fiscal year, charge-offs			4
Term loans by origination year, four years before current fiscal year, charge-offs			6
Term loans by origination year, more than five years before current fiscal year, charge-offs			6
Revolving loans, charge-offs			226
Revolving loans converted to term loans, charge-offs			0
Loan charge-offs, loans	126	85	374	209
Total Commercial [Member] | Commercial and industrial loans [Member] | Pass [Member]
Financing Receivable, Excluding Accrued Interest, before Allowance for Credit Loss, by Origination Year [Abstract]
Term loans by origination year, current fiscal year, finance receivable	32,939		32,939		61,646
Term loans by origination year, fiscal year before current fiscal year, finance receivable	42,757		42,757		31,376
Term loans by origination year, two years before current fiscal year, finance receivable	23,556		23,556		11,128
Term loans by origination year, three years before current fiscal year, finance receivable	9,084		9,084		13,656
Term loans by origination year, four years before current fiscal year, finance receivable	12,495		12,495		3,285
Term loans by origination year, more than five years before current fiscal year, finance receivable	5,914		5,914		5,739
Revolving loans, finance receivable	242,720		242,720		247,594
Revolving loans converted to term loans, finance receivable	383		383		842
Total loans	369,848		369,848		375,266
Total Commercial [Member] | Commercial and industrial loans [Member] | Criticized [Member]
Financing Receivable, Excluding Accrued Interest, before Allowance for Credit Loss, by Origination Year [Abstract]
Term loans by origination year, current fiscal year, finance receivable	721		721		872
Term loans by origination year, fiscal year before current fiscal year, finance receivable	1,311		1,311		1,244
Term loans by origination year, two years before current fiscal year, finance receivable	1,392		1,392		478
Term loans by origination year, three years before current fiscal year, finance receivable	429		429		505
Term loans by origination year, four years before current fiscal year, finance receivable	245		245		665
Term loans by origination year, more than five years before current fiscal year, finance receivable	528		528		532
Revolving loans, finance receivable	8,053		8,053		7,244
Revolving loans converted to term loans, finance receivable	0		0		0
Total loans	12,679		12,679		11,540
Total Commercial [Member] | Commercial real estate [Member]
Financing Receivable, Excluding Accrued Interest, before Allowance for Credit Loss, by Origination Year [Abstract]
Term loans by origination year, current fiscal year, finance receivable	14,069		14,069		40,807
Term loans by origination year, fiscal year before current fiscal year, finance receivable	39,285		39,285		41,503
Term loans by origination year, two years before current fiscal year, finance receivable	38,048		38,048		17,529
Term loans by origination year, three years before current fiscal year, finance receivable	14,743		14,743		19,367
Term loans by origination year, four years before current fiscal year, finance receivable	16,057		16,057		11,675
Term loans by origination year, more than five years before current fiscal year, finance receivable	23,522		23,522		17,847
Revolving loans, finance receivable	6,537		6,537		6,924
Revolving loans converted to term loans, finance receivable	225		225		150
Total loans	152,486		152,486		155,802
Financing Receivable, Excluding Accrued Interest, Allowance for Credit Loss, Writeoff, by Origination Year [Abstract]
Term loans by origination year, current fiscal year, charge-offs			1
Term loans by origination year, fiscal year before current fiscal year, charge-offs			79
Term loans by origination year, two years before current fiscal year, charge-offs			0
Term loans by origination year, three years before current fiscal year, charge-offs			0
Term loans by origination year, four years before current fiscal year, charge-offs			80
Term loans by origination year, more than five years before current fiscal year, charge-offs			44
Revolving loans, charge-offs			0
Revolving loans converted to term loans, charge-offs			0
Loan charge-offs, loans	96	3	204	6
Total Commercial [Member] | Commercial real estate [Member] | Pass [Member]
Financing Receivable, Excluding Accrued Interest, before Allowance for Credit Loss, by Origination Year [Abstract]
Term loans by origination year, current fiscal year, finance receivable	12,148		12,148		38,022
Term loans by origination year, fiscal year before current fiscal year, finance receivable	35,116		35,116		38,709
Term loans by origination year, two years before current fiscal year, finance receivable	33,719		33,719		16,564
Term loans by origination year, three years before current fiscal year, finance receivable	12,832		12,832		16,409
Term loans by origination year, four years before current fiscal year, finance receivable	13,182		13,182		10,587
Term loans by origination year, more than five years before current fiscal year, finance receivable	21,051		21,051		16,159
Revolving loans, finance receivable	6,193		6,193		6,765
Revolving loans converted to term loans, finance receivable	225		225		150
Total loans	134,466		134,466		143,365
Total Commercial [Member] | Commercial real estate [Member] | Criticized [Member]
Financing Receivable, Excluding Accrued Interest, before Allowance for Credit Loss, by Origination Year [Abstract]
Term loans by origination year, current fiscal year, finance receivable	1,921		1,921		2,785
Term loans by origination year, fiscal year before current fiscal year, finance receivable	4,169		4,169		2,794
Term loans by origination year, two years before current fiscal year, finance receivable	4,329		4,329		965
Term loans by origination year, three years before current fiscal year, finance receivable	1,911		1,911		2,958
Term loans by origination year, four years before current fiscal year, finance receivable	2,875		2,875		1,088
Term loans by origination year, more than five years before current fiscal year, finance receivable	2,471		2,471		1,688
Revolving loans, finance receivable	344		344		159
Revolving loans converted to term loans, finance receivable	0		0		0
Total loans	18,020		18,020		12,437
Total Commercial [Member] | Lease financing [Member]
Net Investment in Lease, before Allowance for Credit Loss [Abstract]
Term loans by origination year, current fiscal year, net investment in lease	4,499		4,499		4,873
Term loans by origination year, fiscal year before current fiscal year, net investment in lease	4,417		4,417		3,611
Term loans by origination year, two years before current fiscal year, net investment in lease	2,843		2,843		2,180
Term loans by origination year, three years before current fiscal year, net investment in lease	1,468		1,468		1,596
Term loans by origination year, four years before current fiscal year, net investment in lease	1,039		1,039		859
Term loans by origination year, more than five years before current fiscal year, net investment in lease	1,772		1,772		1,789
Revolving loans, net investment in lease	0		0		0
Revolving loans converted to term loans, net investment in lease	0		0		0
Lease financing	16,038		16,038		14,908
Net Investment in Lease, Allowance for Credit Loss, Writeoff, by Origination Year [Abstract]
Net investment in lease by origination year, current fiscal year, charge-offs			1
Net investment in lease by origination year, year before current fiscal year, charge-offs			5
Net investment in lease by origination year, two years before current fiscal year, charge-offs			6
Net investment in lease by origination year, three years before current fiscal year, charge-offs			4
Net investment in lease by origination year, four years before current fiscal year, charge-offs			3
Net investment in lease by origination year, more than five years before current fiscal year, charge-offs			2
Net investment in lease, revolving loans, charge-offs			0
Net investment in lease, revolving loans converted to term loans, charge-offs			0
Loan charge-offs, lease financing	8	$ 11	21	$ 20
Total Commercial [Member] | Lease financing [Member] | Pass [Member]
Net Investment in Lease, before Allowance for Credit Loss [Abstract]
Term loans by origination year, current fiscal year, net investment in lease	4,229		4,229		4,543
Term loans by origination year, fiscal year before current fiscal year, net investment in lease	4,078		4,078		3,336
Term loans by origination year, two years before current fiscal year, net investment in lease	2,588		2,588		1,990
Term loans by origination year, three years before current fiscal year, net investment in lease	1,340		1,340		1,427
Term loans by origination year, four years before current fiscal year, net investment in lease	927		927		765
Term loans by origination year, more than five years before current fiscal year, net investment in lease	1,682		1,682		1,752
Revolving loans, net investment in lease	0		0		0
Revolving loans converted to term loans, net investment in lease	0		0		0
Lease financing	14,844		14,844		13,813
Total Commercial [Member] | Lease financing [Member] | Criticized [Member]
Net Investment in Lease, before Allowance for Credit Loss [Abstract]
Term loans by origination year, current fiscal year, net investment in lease	270		270		330
Term loans by origination year, fiscal year before current fiscal year, net investment in lease	339		339		275
Term loans by origination year, two years before current fiscal year, net investment in lease	255		255		190
Term loans by origination year, three years before current fiscal year, net investment in lease	128		128		169
Term loans by origination year, four years before current fiscal year, net investment in lease	112		112		94
Term loans by origination year, more than five years before current fiscal year, net investment in lease	90		90		37
Revolving loans, net investment in lease	0		0		0
Revolving loans converted to term loans, net investment in lease	0		0		0
Lease financing	$ 1,194		$ 1,194		$ 1,095