Loans and Related Allowance for Credit Losses (Commercial Lending Asset Quality Indicators) (Details) - USD ($) $ in Millions		3 Months Ended		9 Months Ended		12 Months Ended
		Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023	Dec. 31, 2023
Financing Receivable, Excluding Accrued Interest, before Allowance for Credit Loss, by Origination Year [Abstract]
Total loans, net	[1]	$ 321,381		$ 321,381		$ 321,508
Gross charge-offs
Total		376	$ 233	1,081	$ 808
Commercial
Financing Receivable, Excluding Accrued Interest, before Allowance for Credit Loss, by Origination Year [Abstract]
Year one		20,398		20,398		29,806
Year two		24,293		24,293		39,814
Year three		31,472		31,472		12,512
Year four		10,025		10,025		9,535
Year five		7,901		7,901		10,387
Prior		27,477		27,477		23,271
Revolving Loans		98,431		98,431		93,609
Revolving Loans Converted to Term		724		724		624
Total loans, net		220,721		220,721		219,558
Gross charge-offs
Year one				16		29
Year two				33		36
Year three				51		37
Year four				28		24
Year five				8		35
Prior				272		164
Revolving Loans				86		105
Revolving Loans Converted to Term				52		12
Total		200	$ 72	546	$ 327	442
Commercial | Commercial and industrial
Financing Receivable, Excluding Accrued Interest, before Allowance for Credit Loss, by Origination Year [Abstract]
Year one		17,270		17,270		23,857
Year two		17,198		17,198		28,438
Year three		20,619		20,619		8,301
Year four		6,408		6,408		6,114
Year five		5,120		5,120		4,391
Prior		13,590		13,590		12,680
Revolving Loans		98,022		98,022		93,175
Revolving Loans Converted to Term		664		664		624
Total loans, net		178,891		178,891		177,580
Gross charge-offs
Year one				16		25
Year two				23		32
Year three				43		33
Year four				22		8
Year five				4		3
Prior				4		26
Revolving Loans				86		105
Revolving Loans Converted to Term				52		12
Total				250		244
Commercial | Commercial real estate
Financing Receivable, Excluding Accrued Interest, before Allowance for Credit Loss, by Origination Year [Abstract]
Year one		1,815		1,815		4,337
Year two		5,672		5,672		9,871
Year three		9,565		9,565		3,441
Year four		3,012		3,012		2,680
Year five		2,216		2,216		5,509
Prior		12,355		12,355		9,164
Revolving Loans		409		409		434
Revolving Loans Converted to Term		60		60
Total loans, net		35,104		35,104		35,436
Gross charge-offs
Year one
Year two				5
Year three
Year four				2		12
Year five				1		31
Prior				263		137
Revolving Loans
Revolving Loans Converted to Term
Total				271		180
Commercial | Equipment lease financing
Financing Receivable, Excluding Accrued Interest, before Allowance for Credit Loss, by Origination Year [Abstract]
Year one		1,313		1,313		1,612
Year two		1,423		1,423		1,505
Year three		1,288		1,288		770
Year four		605		605		741
Year five		565		565		487
Prior		1,532		1,532		1,427
Revolving Loans
Revolving Loans Converted to Term
Total loans, net		6,726		6,726		6,542
Gross charge-offs
Year one						4
Year two				5		4
Year three				8		4
Year four				4		4
Year five				3		1
Prior				5		1
Revolving Loans
Revolving Loans Converted to Term
Total				25		18
Pass Rated | Commercial | Commercial and industrial
Financing Receivable, Excluding Accrued Interest, before Allowance for Credit Loss, by Origination Year [Abstract]
Year one		16,786		16,786		23,019
Year two		16,119		16,119		26,657
Year three		18,362		18,362		7,562
Year four		5,682		5,682		5,783
Year five		4,954		4,954		4,110
Prior		12,864		12,864		11,982
Revolving Loans		92,692		92,692		88,467
Revolving Loans Converted to Term		600		600		573
Total loans, net		168,059		168,059		168,153
Pass Rated | Commercial | Commercial real estate
Financing Receivable, Excluding Accrued Interest, before Allowance for Credit Loss, by Origination Year [Abstract]
Year one		1,717		1,717		4,182
Year two		5,419		5,419		8,571
Year three		7,664		7,664		2,986
Year four		2,514		2,514		2,190
Year five		1,763		1,763		4,887
Prior		10,273		10,273		7,411
Revolving Loans		390		390		383
Revolving Loans Converted to Term		9		9
Total loans, net		29,749		29,749		30,610
Pass Rated | Commercial | Equipment lease financing
Financing Receivable, Excluding Accrued Interest, before Allowance for Credit Loss, by Origination Year [Abstract]
Year one		1,267		1,267		1,522
Year two		1,318		1,318		1,424
Year three		1,206		1,206		689
Year four		544		544		690
Year five		538		538		452
Prior		1,496		1,496		1,378
Revolving Loans
Revolving Loans Converted to Term
Total loans, net		6,369		6,369		6,155
Criticized | Commercial | Commercial and industrial
Financing Receivable, Excluding Accrued Interest, before Allowance for Credit Loss, by Origination Year [Abstract]
Year one		484		484		838
Year two		1,079		1,079		1,781
Year three		2,257		2,257		739
Year four		726		726		331
Year five		166		166		281
Prior		726		726		698
Revolving Loans		5,330		5,330		4,708
Revolving Loans Converted to Term		64		64		51
Total loans, net		10,832		10,832		9,427
Criticized | Commercial | Commercial real estate
Financing Receivable, Excluding Accrued Interest, before Allowance for Credit Loss, by Origination Year [Abstract]
Year one		98		98		155
Year two		253		253		1,300
Year three		1,901		1,901		455
Year four		498		498		490
Year five		453		453		622
Prior		2,082		2,082		1,753
Revolving Loans		19		19		51
Revolving Loans Converted to Term		51		51
Total loans, net		5,355		5,355		4,826
Criticized | Commercial | Equipment lease financing
Financing Receivable, Excluding Accrued Interest, before Allowance for Credit Loss, by Origination Year [Abstract]
Year one		46		46		90
Year two		105		105		81
Year three		82		82		81
Year four		61		61		51
Year five		27		27		35
Prior		36		36		49
Revolving Loans
Revolving Loans Converted to Term
Total loans, net		$ 357		$ 357		$ 387

[1] Our consolidated assets included the following for which we have elected the fair value option: Loans held for sale of $0.7 billion, Loans held for investment of $1.2 billion and Other assets of $0.1 billion at September 30, 2024. Comparable amounts at December 31, 2023 were $0.7 billion, $1.2 billion and $0.1 billion, respectively.